WO2024071417A1 - Dry etching residue removing solution - Google Patents

Dry etching residue removing solution Download PDF

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Publication number
WO2024071417A1
WO2024071417A1 PCT/JP2023/035770 JP2023035770W WO2024071417A1 WO 2024071417 A1 WO2024071417 A1 WO 2024071417A1 JP 2023035770 W JP2023035770 W JP 2023035770W WO 2024071417 A1 WO2024071417 A1 WO 2024071417A1
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ions
dry etching
ion
group
solution
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PCT/JP2023/035770
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French (fr)
Japanese (ja)
Inventor
優人 鑓水
由樹 吉川
伴光 佐藤
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株式会社トクヤマ
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Publication of WO2024071417A1 publication Critical patent/WO2024071417A1/en

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    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
    • C11D3/395—Bleaching agents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching

Definitions

  • the present invention relates to a residue removal solution for removing residues after dry etching in the manufacturing process of semiconductor devices.
  • wiring layers are formed for the purpose of extracting electrical signals generated by transistors to the outside.
  • Semiconductor devices are becoming finer year by year, and if a material with low electromigration resistance or high resistance is used, it will lead to a decrease in reliability of the semiconductor device and an impairment of high-speed operation. Therefore, materials with high electromigration resistance and low resistance are desired as wiring materials. For example, aluminum and copper have been used so far as such materials, and recently, tungsten, cobalt, molybdenum, ruthenium, etc. are being considered.
  • Forming a wiring layer on a semiconductor device includes a process of processing the wiring material, and this process uses dry or wet etching.
  • RuO 4 - or RuO 4 2- changes to RuO 4 in the residue remover, and a part of it gasifies and is released into the gas phase.
  • RuO 4 is not only harmful to the human body because of its strong oxidizing properties, but is also easily reduced to produce RuO 2 particles. In general, particles are a major problem in the semiconductor formation process because they cause a decrease in yield. In this context, it is very important to suppress the generation of RuO 4 gas.
  • Patent Document 1 proposes a semiconductor wafer residue remover solution that contains hypochlorite ions and exhibits a good etching rate and stability of the rate, and is also capable of suppressing the generation of RuO 4 gas.
  • Patent Document 2 proposes a semiconductor wafer residue remover solution that contains hypobromite ions and has a good etching rate and a stable etching rate, and is also capable of suppressing the generation of RuO4 gas.
  • an object of the present invention is to provide an etching residue removing solution which has a high etching residue removing effect and further has an oxidizing agent with good storage stability in the solution.
  • the present inventors have conducted extensive research to solve the above problems. That is, the present invention is configured as follows.
  • a dry etching residue removal solution for removing residues after dry etching comprising one or more oxidizing agents selected from the group consisting of hypobromite ions, bromite ions, bromate ions, hypochlorite ions, chlorite ions, and chlorate ions, one or more metals selected from the group consisting of Mg, Ca, Na, and K, and water;
  • the dry etching residue removing solution has a pH of 9.5 or more and 14 or less at 25° C., and the total content of Mg, Ca, Na, and K in the dry etching residue removing solution is 0.01 ppt or more and 1000 ppt or less.
  • Item 3. The dry etching residue removing solution according to Item 1, wherein the oxidizing agent is hypochlorite ions, and the concentration of the hypochlorite ions is 0.001 mol/L or more and 0.40 mol/L or less.
  • Item 4 The dry etching residue removing solution according to Item 2, wherein the oxidizing agent is hypobromite ions, and the concentration of the hypobromite ions is 0.001 mol/L or more and 0.20 mol/L or less.
  • the dry etching residue removing solution according to any one of Items 1 to 4, further comprising an onium ion, and the surface tension of the residue removing solution is 60 mN/m or more and 75 mN/m or less.
  • Item 6 The dry etching residue removing solution according to Item 5, wherein the onium ion is one or more selected from the group consisting of onium ions represented by formulas (1) to (6).
  • R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently an alkyl group having 2 to 9 carbon atoms, an allyl group, an aralkyl group having an alkyl group having 1 to 9 carbon atoms, or an aryl group.
  • At least one hydrogen atom in the aryl group in the aralkyl group and in the ring of the aryl group may be replaced by fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkenyloxy group having 2 to 9 carbon atoms, and in these groups, at least one hydrogen atom may be replaced by fluorine, chlorine, bromine or iodine.
  • A is an ammonium ion or a phosphonium ion.
  • Z is an aromatic group or an alicyclic group which may contain nitrogen, sulfur or oxygen atoms, and in the aromatic group or the alicyclic group, carbon or nitrogen may have chlorine, bromine, fluorine, iodine, at least one alkyl group having 1 to 9 carbon atoms, at least one alkenyloxy group having 2 to 9 carbon atoms, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
  • R is chlorine, bromine, fluorine, iodine, an alkyl group having 1 to 9 carbon atoms, an allyl group, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
  • n is an integer of 1 or 2 and indicates the number of R. When n is 2, R may be the same or different and may form a ring.
  • a is an integer from 1 to 10.
  • a method for removing dry etching residues from a semiconductor wafer comprising the step of contacting the semiconductor wafer with the dry etching residue removing solution according to any one of items 1 to 7.
  • Item 9 A method for manufacturing a semiconductor device, comprising the steps of dry etching a semiconductor wafer and removing dry etching residues with the dry etching residue removing solution according to any one of Items 1 to 7.
  • Item 10 The method for producing a semiconductor device according to item 9, wherein the semiconductor wafer is a semiconductor wafer containing a ruthenium-based metal.
  • the present invention provides a dry etching residue removal solution that can remove residues on a substrate caused by dry etching in the manufacturing process of semiconductor devices with high efficiency, has excellent storage stability, and maintains the smoothness of the surface of the workpiece, as described below.
  • the dry etching residue removal solution of the present invention is characterized by being a composition containing a specific metal, which will be described later. Furthermore, in the present invention, the dry etching residue removal solution (i.e., the chemical solution used to remove residues after dry etching) is also referred to as the residue removal solution.
  • the workpiece (etching target) to which the residue removing solution of the present invention is applied is a semiconductor wafer containing a transition metal.
  • the manufacturing method of the workpiece is not particularly limited.
  • the workpiece is obtained by the following method.
  • a substrate such as silicon is subjected to an oxidation treatment to form a silicon oxide film on the substrate, and an interlayer insulating film is formed thereon.
  • a photoresist film is formed on the interlayer insulating film, and a via hole is formed in the interlayer insulating film.
  • a metal film is formed in the formed via hole.
  • transition metals include tantalum, silicon, copper, hafnium, zirconium, aluminum, vanadium, cobalt, nickel, manganese, gold, rhodium, palladium, titanium, tungsten, molybdenum, platinum, iridium, and ruthenium, and may contain oxides, nitrides, and silicides thereof. In terms of high electromigration resistance and low resistance value, tungsten, cobalt, molybdenum, and ruthenium are preferred, and ruthenium is particularly preferred.
  • the metal film contained in the workpiece may be formed by any method, such as CVD, ALD, PVD, sputtering, plating, and the like.
  • Dry etching residues are by-products generated by dry etching and are part of the above-mentioned processed object. Examples of the residues include Si-containing residues, metal-containing residues, and organic matter-containing residues derived from photoresist.
  • the dry etching residue removing solution (residue removing solution) of the present invention is a chemical solution used to remove residues generated on a substrate by performing dry etching.
  • the residue removing solution of the present invention contains one or more oxidizing agents selected from the group consisting of hypobromite ions, bromite ions, hypochlorite ions, and chlorate ions, a specific metal described below, and water.
  • Hypochlorite ions and hypobromite ions are oxidizing agents having strong oxidizing properties, and the residue removal solution of the present invention containing hypochlorite ions or hypobromite ions or the like can rapidly etch transition metals under alkaline conditions.
  • the object to be treated is ruthenium
  • the generation of RuO4 gas during etching can be suppressed. This not only improves the wafer processing efficiency per unit time, but also suppresses the yield reduction caused by RuO2 particles, and enables safe processing for the human body, achieving both manufacturing cost and safety.
  • ruthenium can be etched at a stable etching rate while suppressing the generation of RuO4 gas.
  • an oxidizing agent By adding an oxidizing agent to the dry etching residue removing solution of the present invention, it is possible to add a function of removing metals contained in dry etching residues. Furthermore, by adding an oxidizing agent to an alkaline dry etching residue removing solution, it has the effect of decomposing and peeling off organic matter-containing residues, and in an alkaline aqueous solution, the surface potential of the insoluble inorganic matter-containing residues and the treated object is negatively charged, so that the electrostatic repulsion effect prevents the insoluble inorganic matter-containing residues from reattaching to a substrate or the like.
  • the type of oxidizing agent is not particularly limited, and examples thereof include hydrogen peroxide, ozone, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodous acid, iodous acid, iodic acid, periodic acid (orthoperiodic acid, metaperiodic acid), salts thereof, and ions generated by dissociation of these salts, as well as one or more selected from the group consisting of hydrogen peroxide, ozone, fluorine, chlorine, bromine, iodine, permanganate, chromate, dichromate, and cerium salts.
  • hypobromite ion, bromite ion, bromate ion, hypochlorite ion, chlorite ion, chlorate ion, hypoiodite ion, iodite ion, iodate ion, and periodate ion are preferred because of their strong oxidizing power, stability, and suitability for use in semiconductor applications, and hypobromite ion, bromate ion, bromite ion, hypochlorite ion, chlorate ion, and chlorite ion are more preferred, and hypobromite ion, bromite ion, hypochlorite ion, and chlorate ion are even more preferred.
  • the concentration of the oxidizing agent in the residue removal solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but may be from 0.0001 mol/L to 0.50 mol/L, and preferably from 0.0001 mol/L to 0.40 mol/L. If the concentration is less than 0.0001 mol/L, the dry etching residue removal efficiency is low and the practicality is low. On the other hand, if the concentration exceeds 0.50 mol/L, the oxidizing agent is more likely to decompose, and the dry etching residue removal efficiency may become unstable.
  • the oxidizing agent contained in the residue removing solution of the present invention may be one or more kinds.
  • the type of the oxidizing agent contained in the second kind different from the first kind is not particularly limited, but for example, hydrogen peroxide, ozone, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodous acid, iodous acid, iodic acid, periodic acid, salts thereof, and ions generated by dissociation of these salts, and further, one or more kinds selected from the group consisting of hydrogen peroxide, ozone, fluorine, chlorine, bromine, iodine, permanganate, chromate, dichromate, and cerium salt can be mentioned.
  • the first kind of oxidizing agent can be hypobromite ion or hypochlorite ion.
  • the residue removal rate may be stabilized, and the stability when reusing the residue removal liquid may be improved.
  • hypobromite ions are included as the first type of oxidizing agent, the hypobromite ions consumed in etching the metal lose their oxidizing power and change to bromide ions. In this case, the more the amount of bromide ions that change to bromide ions, the lower the residue removal ability.
  • the residue removal liquid In semiconductor wafer manufacturing plants, it is common to circulate and reuse the processing liquid from the viewpoint of cost reduction, but if the residue removal ability decreases due to the reuse of the processing liquid, it becomes difficult to stably manufacture semiconductor wafers.
  • multiple types of oxidizing agents are included in the residue removal liquid, for example, when hypochlorite ions are included in addition to hypobromite ions, the bromide ions that have lost their oxidizing power are oxidized by hypochlorite ions and change to hypobromite ions. For this reason, it is possible to suppress the decrease in the concentration of hypobromite ions in the residue removal liquid, and even when the residue removal liquid is reused, the etching rate is less likely to decrease. Furthermore, when the residue removing solution of the present invention contains a plurality of types of oxidizing agents, the total concentration of the oxidizing agents is desirably 0.0001 mol/L or more and 0.40 mol/L or less.
  • the counter cation of the oxidizing agent is not particularly limited, but is preferably a metal ion or an onium ion described later.
  • metal ions include calcium ion, sodium ion, potassium ion, magnesium ion, iron ion, chromium ion, nickel ion, zinc ion, copper ion, and aluminum ion.
  • the counter cation of the oxidizing agent is preferably an onium ion.
  • hypobromite ions may be generated in the residue removal liquid, or may be added to the residue removal liquid as hypobromite.
  • the hypobromite salt referred to here is a salt containing hypobromite ions, or a solution containing the salt.
  • hypobromite ions also written as BrO - or BrO
  • bromine gas may be blown into the residue removal liquid.
  • the residue removal liquid is preferably at 50° C. or less. If the residue removal liquid is at 50° C.
  • the temperature of the residue removal liquid is more preferably at 30° C. or less, and most preferably at 25° C. or less.
  • the temperature of the residue removal solution is preferably ⁇ 35° C. or higher, more preferably ⁇ 15° C. or higher, and most preferably 0° C. or higher.
  • the pH of the residue removal solution into which the bromine gas is blown is blown, but if the pH of the residue removal solution is alkaline, it can be used to remove dry etching residues immediately after hypobromite ions are generated.
  • the solubility of bromine gas (Br 2 ) is improved if the residue removal liquid contains bromide ions (Br - ). This is because Br 2 dissolved in the residue removal liquid reacts with Br - or Br 3 - to form complex ions such as Br 3 - or Br 5 - , which are stabilized in the residue removal liquid.
  • a residue removal liquid containing a large amount of Br 2 , Br - , Br 3 - , Br 5 - or the like can generate more hypobromite ions, and is therefore suitable for use as the residue removal liquid of the present invention.
  • hypobromite ions can be produced in the residue removal solution by oxidizing bromine-containing compounds with an oxidizing agent.
  • hypobromite a compound to the residue removal solution
  • hypobromite, bromine water, and/or hypobromite may be added.
  • hypobromite sodium hypobromite, potassium hypobromite, and tetraalkylammonium hypobromite are preferable, and hypobromite or tetraalkylammonium hypobromite are more preferable because they are substantially free of metal ions that are problematic in semiconductor manufacturing.
  • tetraalkylammonium hypobromite can be easily obtained by passing bromine gas through a tetraalkylammonium hydroxide solution. It can also be obtained by mixing hypobromous acid with a tetraalkylammonium hydroxide solution. Furthermore, tetraalkylammonium hypobromite can also be obtained by replacing the cations contained in hypobromites such as sodium hypobromite with tetraalkylammonium ions using an ion exchange resin.
  • the concentration of the hypobromite ions in the residue removal solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less in terms of hypobromite ions. If the concentration is less than 0.001 mol/L, the dry etching residue removal efficiency is low and practicality is low. On the other hand, if the concentration exceeds 0.20 mol/L, decomposition of the hypobromite ions is likely to occur, making it difficult to stabilize the dry etching residue removal efficiency.
  • the concentration of the hypobromite ions is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.005 mol/L or more and 0.20 mol/L or less, and most preferably 0.01 mol/L or more and 0.10 mol/L or less.
  • the ratio of hypobromite ions in 1 mole of bromine element contained in the residue removal solution exceeds 0.5 moles.
  • hypobromite ions are easily converted to Br - by the oxidation reaction or decomposition reaction of ruthenium. Since Br - does not etch metal-containing residues, it is important for stable dry etching residue removal to quickly oxidize Br - in the residue removal solution to hypobromite ions and maintain a high concentration of chemical species (hypobromite ions; BrO - ) having high dry etching residue removal ability.
  • the ratio of hypobromite ions in 1 mole of bromine element contained in the residue removal solution of the present invention exceeds 0.5 moles, that is, when more than half of the bromine elements of the total bromine elements in the residue removal solution are present as BrO - , the concentration of chemical species having dry etching residue removal ability can be considered to be sufficiently high, and the dry etching residue removal efficiency is stabilized.
  • the concentration of hypobromite ions in the residue removal solution can be confirmed using widely known methods. For example, by using ultraviolet-visible spectrophotometry, the absorption caused by hypobromite ions can be easily confirmed, and the hypobromite ion concentration can be calculated from the intensity of the absorption peak (approximately around 330 nm, depending on the pH of the residue removal solution and the hypobromite ion concentration, etc.). Furthermore, the hypobromite ion concentration can also be calculated by iodine titration. The hypobromite ion concentration can also be calculated from the oxidation-reduction potential (ORP) of the residue removal solution.
  • ORP oxidation-reduction potential
  • Measurement by ultraviolet-visible spectrophotometry is the most preferable from the viewpoint of non-contact and continuous measurement. Note that when measuring the hypobromite ion concentration by ultraviolet-visible spectrophotometry, if there is absorption due to other chemical species, the hypobromite ion concentration can be calculated with sufficient accuracy by performing data processing such as spectrum division and baseline correction, and appropriate selection of a reference.
  • the storage stability of the solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
  • the concentration of the bromite ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less in terms of the amount of bromite ion. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is low and practicality is low.
  • the concentration of the bromite ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
  • the bromite ions may be generated in the residue removal solution, or may be added to the residue removal solution as a bromite salt.
  • the bromite salt referred to here means a salt containing bromite ions or a solution containing the salt.
  • bromite ions can be produced in the residue removal solution by oxidizing bromine-containing compounds with an oxidizing agent. To add bromite ions as a compound to the residue removal solution, bromite, bromine water, and/or a bromite may be added.
  • bromite sodium bromite, potassium bromite, and tetraalkylammonium bromite are preferable, and bromite or tetraalkylammonium bromite are more preferable in that they are substantially free of metal ions that are problematic in semiconductor manufacturing.
  • the concentration of bromite ions in the residue removal solution can be confirmed by using widely known methods. For example, by using ultraviolet-visible spectrophotometry, the absorption caused by bromite ions can be easily confirmed, and the bromite ion concentration can be calculated from the intensity of the absorption peak (approximately around 298 nm, depending on the pH of the residue removal solution and the bromite ion concentration, etc.). Furthermore, the bromite ion concentration can also be calculated by iodine titration. The bromite ion concentration can also be calculated from the oxidation-reduction potential (ORP) of the residue removal solution. Measurement by ultraviolet-visible spectrophotometry is the most preferable from the viewpoint of non-contact and continuous measurement.
  • the bromite ion concentration when measuring the bromite ion concentration by ultraviolet-visible spectrophotometry, if there is absorption due to other chemical species, the bromite ion concentration can be calculated with sufficient accuracy by performing data processing such as spectrum division and baseline correction, and appropriate selection of a reference.
  • the storage stability of the solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
  • the concentration of the bromate ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less in terms of the amount of bromate ion. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is small and the practicality is low.
  • the concentration of the bromate ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
  • the bromate ions may be generated in the residue-removing solution, or may be added to the residue-removing solution as a bromate salt.
  • the bromate referred to here means a salt containing bromate ions, or a solution containing the salt.
  • bromate ions can be produced in the residue removal solution by oxidizing a bromine-containing compound with an oxidizing agent.
  • Bromate ions can be added as a compound to the residue removal solution by adding bromic acid and/or a bromate salt.
  • the bromate salt sodium bromate, potassium bromate, and tetraalkylammonium bromate are preferable, and bromic acid or tetraalkylammonium bromate is more preferable in that it does not contain metal ions that are problematic in semiconductor manufacturing.
  • the concentration of bromate ions in the residue-removed liquid can be confirmed by using a widely known method.
  • the peak of bromate ions can be easily confirmed, and the concentration of bromate ions in the liquid can be obtained from the intensity and peak area of the absorption peak.
  • the concentration of bromate ions can be obtained from the oxidation-reduction potential (ORP) of the residue-removed liquid, liquid chromatography mass spectrometry (LC/MS), and tandem mass spectrometry (LC/MS/MS).
  • hypochlorite ion When the dry etching residue removing solution of the present invention contains hypochlorite ions (also written as ClO ⁇ or ClO), the storage stability of the chemical solution can be improved when the concentration is 0.001 mol/L or more and 0.40 mol/L or less.
  • the hypochlorite ions may be generated in the residue removing liquid, or may be added to the residue removing liquid as hypochlorite.
  • the hypochlorite salt referred to here is a salt containing hypochlorite ions, or a solution containing the salt.
  • chlorine gas may be blown into the residue removing liquid.
  • the residue removing liquid is preferably at 50°C or lower. If the residue removing liquid is at 50°C or lower, not only can hypochlorite ions be efficiently generated, but the generated hypochlorite ions can be stably used for removing dry etching residues. Furthermore, in order to dissolve more chlorine in the residue removing liquid, the temperature of the residue removing liquid is more preferably at 30°C or lower, and most preferably at 25°C or lower. The lower limit of the temperature of the residue removing liquid is not particularly limited, but it is preferable that the residue removing liquid does not freeze.
  • the residue removing liquid is preferably at -35°C or higher, more preferably at -15°C or higher, and most preferably at 0°C or higher.
  • the pH of the residue removal solution into which the chlorine gas is blown is not particularly limited, but if the pH of the residue removal solution is alkaline, it can be used to remove dry etching residues immediately after hypochlorite ions are generated.
  • hypochlorite ions when hypochlorite ions are generated by blowing chlorine gas into the residue removal liquid, the solubility of chlorine gas (Cl 2 ) is improved if the residue removal liquid contains chloride ions (Cl - ). This is because Cl 2 dissolved in the residue removal liquid reacts with Cl - or Cl 3 - to form complex ions such as Cl 3 - or Cl 5 - , which are stabilized in the residue removal liquid.
  • a residue removal liquid containing a large amount of Cl 2 , Cl - , Cl 3 - , Cl 5 - or the like can generate more hypochlorite ions, and therefore can be suitably used as the residue removal liquid of the present invention.
  • hypochlorite ions can be produced in the residue removal solution by oxidizing chlorine-containing compounds with an oxidizing agent.
  • hypochlorous acid chlorine water, and/or hypochlorite may be added.
  • hypochlorite sodium hypochlorite, potassium hypochlorite, and tetraalkylammonium hypochlorite are preferable, and hypochlorous acid or tetraalkylammonium hypochlorite is more preferable because it is substantially free of metal ions that are problematic in semiconductor manufacturing.
  • the tetraalkylammonium hypochlorite can be easily obtained by passing chlorine gas through a tetraalkylammonium hydroxide solution.
  • hypochlorous acid can also be mixed with a tetraalkylammonium hydroxide solution.
  • tetraalkylammonium hypochlorite can also be obtained by replacing the cation contained in hypochlorite such as sodium hypochlorite with tetraalkylammonium ion using ion exchange resin.
  • the concentration of the hypochlorite ions in the residue removal solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.40 mol/L or less in terms of hypochlorite ions. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is low and practicality is low. On the other hand, if it exceeds 0.40 mol/L, decomposition of the hypochlorite ions is likely to occur, and the dry etching residue removal efficiency becomes less stable.
  • the concentration of the hypochlorite ions is preferably 0.001 mol/L or more and 0.40 mol/L or less, more preferably 0.01 mol/L or more and 0.30 mol/L or less, and most preferably 0.1 mol/L or more and 0.20 mol/L or less.
  • the concentration of hypochlorite ions in the residue removal solution can be confirmed using widely known methods. For example, by using ultraviolet-visible spectrophotometry, the absorption caused by hypochlorite ions can be easily confirmed, and the hypochlorite ion concentration can be calculated from the intensity of the absorption peak (approximately around 292 nm, depending on the pH of the residue removal solution and the hypochlorite ion concentration, etc.). Furthermore, the hypochlorite ion concentration can also be calculated by iodometric titration. The hypochlorite ion concentration can also be calculated from the oxidation-reduction potential (ORP) of the residue removal solution.
  • ORP oxidation-reduction potential
  • Measurement by ultraviolet-visible spectrophotometry is the most preferable from the viewpoint of non-contact and continuous measurement. Note that when measuring the hypochlorite ion concentration by ultraviolet-visible spectrophotometry, if there is absorption due to other chemical species, the hypochlorite ion concentration can be calculated with sufficient accuracy by performing data processing such as spectrum division and baseline correction, and appropriate selection of a reference.
  • the storage stability of the chemical solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
  • the concentration of the chlorite ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less as the amount of chlorite ion. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is small and practical.
  • the concentration of the chlorite ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
  • the chlorite ion may be generated in the residue removing solution, or may be added to the residue removing solution as a chlorite.
  • the chlorite salt referred to here means a salt containing chlorite ion or a solution containing the salt.
  • chlorite ions can be produced in the residue removal solution by oxidizing chlorine-containing compounds with an oxidizing agent.
  • chlorous acid, chlorine water, and/or a chlorite may be added.
  • chlorite sodium chlorite, potassium chlorite, and tetraalkylammonium chlorite are preferable, and chlorous acid or tetraalkylammonium chlorite is more preferable in that it is substantially free of metal ions that are problematic in semiconductor manufacturing.
  • the concentration of chlorite ions in the residue removal solution can be confirmed by using a widely known method. For example, by using ion chromatography analysis, the peak of chlorite ions can be easily confirmed, and the concentration of chlorite ions in the solution can be obtained from the intensity and area of the absorption peak.
  • chlorate ion When the dry etching residue removing solution of the present invention contains chlorate ions (ClO 3 ⁇ , also written as ClO 3 ), the storage stability of the solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
  • the concentration of the chlorate ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but preferably, the amount of chlorate ion is 0.001 mol/L or more and 0.20 mol/L or less. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is small and practical.
  • the concentration of the chlorate ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
  • the chlorate ions may be generated in the residue-removing solution, or may be added to the residue-removing solution as a chlorate salt.
  • the chlorate referred to here means a salt containing chlorate ions, or a solution containing the salt.
  • chlorine-containing compounds can be oxidized with an oxidizing agent to produce chlorate ions in the residue removal solution.
  • chloric acid and/or a chlorate may be added.
  • sodium chlorate, potassium chlorate, and tetraalkylammonium chlorate are preferable, and chloric acid or tetraalkylammonium chlorate is more preferable because it does not contain metal ions that are problematic in semiconductor manufacturing.
  • the concentration of chlorate ion in the residue-removing solution can be confirmed by using a widely known method.For example, by using ion chromatography analysis, the peak of chlorate ion can be easily confirmed, and the concentration of chlorate ion in the solution can be obtained from the intensity and peak area of the absorption peak.Otherwise, the concentration of chlorate ion can be obtained from the oxidation-reduction potential (ORP) of the residue-removing solution.
  • ORP oxidation-reduction potential
  • the acid dissociation constant (pK a ) of hypobromous acid (HBrO) and hypobromite ion (BrO ⁇ ) is 8.6, and the acid dissociation constant (pK a ) of hypochlorous acid (HClO) and hypochlorite ion (ClO ⁇ ) is 7.5, so that when the pH is low, HBrO and BrO ⁇ , or HClO and ClO ⁇ may coexist depending on the pH of the residue removal solution.
  • the residue removal solution contains HBrO and BrO ⁇
  • the total concentration of HBrO and BrO ⁇ may be treated as the concentration of the hypobromite ion.
  • the residue removal solution contains HClO and ClO ⁇
  • the total concentration of HClO and ClO ⁇ may be treated as the concentration of the hypochlorite ion.
  • an acid or an alkali can be added to the residue removal solution.
  • the acid may be either an inorganic acid or an organic acid, and examples include hydrofluoric acid, hydrochloric acid, hydrobromic acid, nitric acid, acetic acid, sulfuric acid, peroxodisulfuric acid, formic acid, carboxylic acids such as acetic acid, and other widely known acids used in residue removal solutions for semiconductors can be used without any restrictions.
  • the alkali it is preferable to use an organic alkali because it does not contain metal ions that are problematic in semiconductor manufacturing.
  • tetraalkylammonium hydroxide which is composed of tetraalkylammonium ions and hydroxide ions.
  • examples of the tetraalkylammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ethyltrimethylammonium hydroxide, propyltrimethylammonium hydroxide, and the like.
  • the organic alkali is preferably tetraalkylammonium hydroxide, and more preferably tetramethylammonium hydroxide, because it has a large number of hydroxide ions per unit weight and is easily available as a high-purity product.
  • the residue removing solution may contain one type of tetraalkylammonium ion, or a combination of two or more types of tetraalkylammonium ions.
  • the dry etching residue removal solution contains one or more metals selected from the group consisting of Mg, Ca, Na, and K in an amount of 0.01 ppt or more and 1000 ppt or less as specific metals, which further has the effect of maintaining the surface smoothness of the workpiece.
  • the target mixture is adsorbed onto the surface of the transition metal-containing material to homogenize the electronic state, and therefore, there is an effect of maintaining the smoothness of the surface of the treated object by containing one or more metals selected from the group consisting of Mg, Ca, Na, and K in the residue removal solution.
  • the total content of one or more metals selected from the group consisting of Mg, Ca, Na, and K contained in the residue removal solution is 0.01 ppt or more and 1000 ppt or less, more preferably 0.01 ppt or more and 200 ppt or less, and even more preferably 0.01 ppt or more and 50 ppt or less.
  • the dry etching residue removal solution may contain only Mg, only Ca, only Na, only K, Mg, Ca, Na, and K, Mg, Ca, and Na, only Mg, Ca, and K, only Mg, Na, and K, only Ca, Na, and K, only Mg and Ca, only Mg and Na, only Mg and K, only Ca and Na, only Ca and K, or only Na and K.
  • the content of a specific metal contained in the etching residue removal solution is the total content of all metals contained therein.
  • the dry etching residue removal solution may contain one or more metals selected from the group consisting of alkali metals other than Mg, Ca, Na, and K, alkaline earth metals, Fe, Cr, Ni, Zn, Cu, and Al. These do not contribute to the smoothness of the surface, but may be contained.
  • the dry etching residue removing solution of the present invention may contain chloride ions, bromide ions, and iodide ions derived from the manufacturing process or raw materials. The contents of these ions may be used without problems as long as they are at concentrations that do not affect the removal of dry etching residues, and each concentration of these ions preferably does not exceed 1 mass %.
  • the residue removal solution contains onium ions, which are effective in maintaining the smoothness of the surface. Since the surface of the workpiece is also etched by the residue removal step, it is required that the smoothness of the surface does not change before and after the treatment. In order to maintain the smoothness of the surface of the workpiece within a preferred range, it is preferable to select one or more types selected from the group consisting of onium ions having structures represented by the following formulas (1) to (6).
  • R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently an alkyl group having 2 to 9 carbon atoms, an allyl group, an aralkyl group having an alkyl group having 1 to 9 carbon atoms, or an aryl group.
  • At least one hydrogen atom in the aryl group in the aralkyl group and in the ring of the aryl group may be replaced by fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkenyloxy group having 2 to 9 carbon atoms, and in these groups, at least one hydrogen atom may be replaced by fluorine, chlorine, bromine or iodine.
  • Examples of counter anions to the onium ions include fluoride ion, chloride ion, bromide ion, iodide ion, hydroxide ion, nitrate ion, phosphate ion, sulfate ion, hydrogen sulfate ion, methanesulfate ion, perchlorate ion, chlorate ion, chlorite ion, hypochlorite ion, perbromate ion, bromate ion, bromite ion, hypobromite ion, orthoperiodate ion, metaperiodate ion, iodate ion, iodite ion, hypoiodite ion, acetate ion, carbonate ion, hydrogen carbonate ion, fluoroborate ion, and trifluoroacetate ion.
  • A is an ammonium ion or a phosphonium ion.
  • Z is an aromatic group or an alicyclic group which may contain nitrogen, sulfur or oxygen atoms, and in the aromatic group or the alicyclic group, carbon or nitrogen may have chlorine, bromine, fluorine, iodine, at least one alkyl group having 1 to 9 carbon atoms, at least one alkenyloxy group having 2 to 9 carbon atoms, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
  • R is chlorine, bromine, fluorine, iodine, an alkyl group having 1 to 9 carbon atoms, an allyl group, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
  • n is an integer of 1 or 2 and indicates the number of R. When n is 2, R may be the same or different and may form a ring.
  • a is an integer from 1 to 10.
  • the residue removal solution contains onium ions, which can suppress the generation of gas due to metal oxides.
  • the object to be treated is ruthenium
  • the ruthenium is oxidized by the oxidizing agent in the residue removal solution to generate RuO 4 - , RuO 4 2- , etc.
  • the generated RuO 4 - , RuO 4 2- , etc. interact with the onium ions to suppress the generation of RuO 4 gas.
  • the concentration of the onium ion in the residue removing solution of the present invention is preferably 1 mass ppm or more and 10,000 mass ppm or less. If the amount of onium ion added is too small, not only the interaction with the workpiece such as RuO 4 - is weakened, for example, the RuO 4 gas suppression effect is reduced, but also the amount of onium ion attached to the metal surface during residue removal is insufficient, so that the surface smoothness tends to decrease. On the other hand, if the amount added is too large, the amount of onium ion adsorbed to the metal surface becomes excessive, and the residue removal rate decreases.
  • the residue removing solution of the present invention preferably contains onium ion in an amount of 1 mass ppm or more and 10,000 mass ppm or less, more preferably 10 mass ppm or more and 5,000 mass ppm or less, and even more preferably 50 mass ppm or more and 2000 mass ppm or less.
  • onium ions When onium ions are added, only one type may be added, or two or more types may be added in combination. Even when two or more types of onium ions are contained, so long as the total concentration of the onium ions is within the above concentration range, the generation of RuO4 gas can be effectively suppressed.
  • onium ions examples include chlorocholine ion, bromocholine, trans-2-butene 1,4-bis(triphenylphosphonium ion), 1-hexyl-3-methylimidazolium ion, allyltriphenylphosphonium ion, tetraphenylphosphonium ion, benzyltriphenylphosphonium ion, methyltriphenylphosphonium ion, (2-carboxyethyl)triphenylphosphonium ion, (3-carboxypropyl)triphenylphosphonium ion, (4-carboxybutyl)triphenylphosphonium ion, (5-carboxypentyl)triphenylphosphonium ion, cinnamyltriphenylphosphonium ion, (2-hydroxybenzyl)triphenylphosphonium ion, (1-naphthylmethyl)triphenylphosphonium ion,
  • the effects of onium ions include suppressing surface roughness during residue removal and suppressing RuO 4 gas, but in addition to this, they also have the effect of improving the number of times of reuse when used as a semiconductor residue removal solution.
  • used residue removal solutions are sometimes recycled through circulation filtration.
  • metals dissolve into the residue removal solution, so the composition of the residue removal solution differs before and after use.
  • ruthenium residue removal using hypobromite ions ruthenium dissolves as RuO 4 - under alkaline conditions.
  • hypobromite ions react with RuO 4 - or RuO 4 2- or RuO 4 generated by changing RuO 4 - , the concentration of hypobromite ions, which are chemical species effective for residue removal, decreases. Therefore, the more times the residue removal solution is reused and the longer the reuse time, the lower the residue removal rate.
  • the stability during reuse may be improved. That is, RuO 4 - and the like react positively with the onium ion, and it becomes possible to suppress the reaction between RuO 4 - and the like and hypobromite ion.
  • an onium ion that can be used for such a purpose a phosphonium ion is preferable.
  • ammonium ion there is a concern that an amine may be generated by reaction with hypobromite ion, and this amine may decompose hypobromite ion.
  • the residue removing liquid contains onium ions and has a surface tension of 60 mN/m or more and 75 mN/m or less. Note that the surface tension is measured at 25° C.
  • the residue removing solution of the present invention contains an oxidizing agent, in order to prevent the stability of the oxidizing agent from decreasing and the inhibition of residue removal from occurring, the surface tension is preferably set to 75 mN/m or less.
  • One method for increasing the surface tension of the residue removal solution is to add a salt containing an anion with a high degree of hydration.
  • a salt containing an anion with a high degree of hydration By adding an anion with a high degree of hydration, the neutralization of the charge of the onium ion by the anion is inhibited, and the electrical repulsion between the onium ions is maintained, thereby increasing the surface tension.
  • anions with a high degree of hydration include fluoride ions, chloride ions, and bromide ions.
  • the surface tension can be measured in accordance with JIS 2241 "Test method using a Wilhelmy surface tensiometer.”
  • onium ions examples include allyltriphenylphosphonium ion, tetraphenylphosphonium ion, trans-2-butene-1,4-bis(triphenylphosphonium ion), benzyltriphenylphosphonium ion, tetrabutylphosphonium ion, tributylhexylphosphonium ion, heptyltriphenylphosphonium ion, cyclopropyltriphenylphosphonium ion, (bromomethyl)triphenylphosphonium ion, (chloromethyl)triphenylphosphonium ion, etc.
  • Ruthenium which is an example of the object to be treated in the present invention, may be a ruthenium-based metal or a ruthenium alloy.
  • the material to be treated is a ruthenium-based metal and the pH is 9.5 or more and 14 or less at 25° C., harmful RuO 4 gas is unlikely to be generated and particles due to RuO 2 are also few.
  • hypobromite ions and hypochlorite ions dissolve ruthenium Although the details of the mechanism by which hypobromite ions and hypochlorite ions dissolve ruthenium are not necessarily clear, it is presumed that hypobromite ions or hypobromous acid generated from hypobromite ions in the residue removal solution, or hypochlorite ions or hypochlorite ions generated from hypochlorite ions in the residue removal solution, oxidize ruthenium to RuO 4 , RuO 4 - or RuO 4 2- , and dissolve in the residue removal solution. By dissolving ruthenium as RuO 4 - or RuO 4 2- , it is possible to reduce the amount of RuO 4 gas generated and suppress the generation of RuO 2 particles.
  • the pH of the residue removal solution is preferably 9.5 or more and 14 or less, more preferably 12 or more and 14 or less, and most preferably 12 or more and less than 13. If the pH of the residue removing solution is 12 or more but less than 13, ruthenium dissolves in the residue removing solution as RuO 4 - or RuO 4 2- , so that the amount of RuO 4 gas generated can be significantly reduced and the generation of RuO 2 particles can be suppressed.
  • ruthenium-based metal refers to ruthenium metal containing 70 atomic % or more of ruthenium, ruthenium oxide ( RuOx ), nitride (RuN), oxynitride (RuNO), etc.
  • ruthenium oxide refers to ruthenium dioxide and ruthenium trioxide (trihydrate).
  • ruthenium alloy refers to an alloy containing 70 atomic % or more and 99.99 atomic % or less of ruthenium and containing a metal other than ruthenium at a concentration higher than the concentration that is inevitably contained. In the present invention, when there is no need to particularly distinguish between ruthenium-based metal and ruthenium alloy, they are described as ruthenium.
  • the ruthenium alloy may contain any metal other than ruthenium.
  • metals contained in the ruthenium alloy include tantalum, silicon, copper, hafnium, zirconium, aluminum, vanadium, cobalt, nickel, manganese, gold, rhodium, palladium, titanium, tungsten, molybdenum, platinum, and iridium, and the alloy may contain oxides, nitrides, and silicides of these metals.
  • These ruthenium compounds may be intermetallic compounds, ionic compounds, or complexes. Ruthenium may be exposed on the surface of the wafer, or may be covered with other metals, metal oxide films, insulating films, resists, or the like.
  • the residue removing solution of the present invention can suppress RuO4 gas generated from very small amounts of dissolved ruthenium even in the case where ruthenium is not actively dissolved, that is, even in the case of a process in which ruthenium is the object of protection.
  • the method for producing a semiconductor device of the present invention includes a step of dry etching a semiconductor wafer, and a step of removing dry etching residues with the above-mentioned dry etching residue removing solution. Furthermore, the method may include a metal film forming step of forming a semiconductor wafer by forming a metal film on a semiconductor substrate before the step of dry etching the semiconductor wafer, and may include a step of rinsing the semiconductor wafer and a step of drying the semiconductor wafer before and/or after the step of removing the dry etching residues.
  • the residue can be removed more efficiently than when only dry etching is used. Furthermore, compared to when only wet etching is used, the surface smoothness of the metal film can be maintained.
  • the semiconductor wafer can be cleaned by contacting the semiconductor wafer with a rinsing liquid.
  • the rinsing liquid can be selected from the group consisting of water, functional water such as ozone water, radical water, and electrolytic ion water, organic solvents such as 2-propanol, ammonia-hydrogen peroxide mixtures, hydrochloric acid-hydrogen peroxide mixtures, sulfuric acid-hydrogen peroxide mixtures, nitric acid-hydrofluoric acid mixtures, hydrofluoric acid, sulfuric acid, phosphoric acid, nitric acid, buffered hydrofluoric acid, ammonia, hydrogen peroxide, hydrochloric acid, tetramethylammonium hydroxide (TMAH), and mixtures of these with water.
  • functional water such as ozone water, radical water, and electrolytic ion water
  • organic solvents such as 2-propanol
  • ammonia-hydrogen peroxide mixtures such as ozone water, radical water, and electrolytic ion water
  • organic solvents such as 2-propanol
  • the step of drying the semiconductor wafer is not particularly limited, but the drying can be performed by spin drying, IPA drying, Marangoni drying, Rotagoni drying, or the like.
  • the method for manufacturing a semiconductor device may also include known steps used in the manufacture of semiconductor devices, such as one or more steps selected from a wafer fabrication step, an oxide film formation step, a transistor formation step, a wiring formation step, and a CMP step.
  • the substrate on which the dry etching is performed is a semiconductor wafer containing a transition metal.
  • the transition metal film may be formed on the substrate by any method, such as CVD, ALD, PVD, sputtering, plating, etc.
  • the dry etching method is not particularly limited and can be performed by a known method, but it is preferable to dry etch using an O 2 /Cl 2 mixed gas.
  • the dry etching is preferably reactive ion etching.
  • capacitive coupled plasma-RIE capacitive coupled plasma-RIE, inductive coupled plasma-RIE, or ECR (Electron Cyclotron Resonance-RIE) is preferable.
  • ECR Electro Cyclotron Resonance-RIE
  • dry etching residues such as Si-containing residues, metal-containing residues, and organic substance-containing residues derived from photoresist are generated.
  • the residue removing solution of the present invention is suitably used for removing these dry etching residues.
  • the residue-removing solution of the present invention can remove dry etching residues from a semiconductor wafer by contacting the semiconductor wafer. That is, the method for removing dry etching residues from a semiconductor wafer of the present invention includes a step of contacting the semiconductor wafer with the residue-removing solution.
  • the method for removing dry etching residues of the present invention can also be used as a method for cleaning semiconductor wafers.
  • the method for cleaning semiconductor wafers also includes a step of contacting the semiconductor wafer with the above-mentioned residue removing solution, similar to the method for removing dry etching residues.
  • the method for bringing the semiconductor wafer into contact with the residue-removing liquid is not particularly limited, and may be appropriately selected according to the cleaning conditions of the cleaning device used and the semiconductor wafer used.
  • a method of spraying the residue-removing liquid onto the semiconductor wafer a method of immersing the semiconductor wafer in a container containing the residue-removing liquid, a method of dripping the residue-removing liquid onto the semiconductor wafer, a method of bringing the semiconductor wafer into contact with the residue-removing liquid and applying ultrasonic waves to promote residue removal, and any combination thereof.
  • the temperature at which the residue removing solution of the present invention is used is in the range of 10 to 80° C., preferably 20 to 70° C., and may be appropriately selected depending on the cleaning conditions of the cleaning device used and the semiconductor wafer used.
  • the time for which the residue removing solution of the present invention is used is 0.1 to 120 minutes, preferably 0.5 to 60 minutes, per wafer, and may be appropriately selected according to the cleaning conditions of the cleaning device used and the semiconductor wafer used.
  • the container for storing the residue removing liquid of the present invention is not particularly limited, but it is preferable that the container is highly clean and that impurities are less likely to be eluted from the container, and the inner surface of the container that comes into contact with the liquid is preferably made of an organic polymer material because it is less likely to elute metal components.
  • the organic polymer material used for the inner surface of the container vinyl chloride resins (soft and hard vinyl chloride resins), nylon resins, silicone resins, polyolefin resins (polyethylene, polypropylene), fluororesins, etc. can be used, and among them, polyolefin resins or fluororesins are preferable in consideration of ease of molding, solvent resistance, and less elution of impurities.
  • a substrate made of silicon was prepared.
  • the prepared substrate was subjected to an oxidation treatment to form a silicon oxide film of 500 nm on the silicon.
  • an interlayer insulating film of 50 nm made of a low dielectric constant (Low-k) film was formed, a photoresist film was formed on the interlayer insulating film, and a via hole was formed in the interlayer insulating film.
  • a ruthenium film of 20 nm was formed in the formed via hole.
  • the workpiece (semiconductor substrate) on which the ruthenium film was formed by the above method was subjected to dry etching treatment using a reactive ion etching apparatus (RIE-400IPC manufactured by Samco Corporation).
  • RIE-400IPC reactive ion etching apparatus
  • the workpiece dry-etched by the above method was cut into 10 x 20 mm pieces.
  • 60 mL of the dry etching residue removal solution was prepared in a fluororesin container with a lid (AsOne, PFA container 94.0 mL).
  • the workpiece after dry etching prepared by the above method was immersed in the dry etching residue removal solution at 30°C for 1 minute.
  • the residue removal rate X ( ⁇ - ⁇ ) / ⁇ ⁇ 100, and was evaluated according to the following criteria. In both cases, evaluations A to C were considered to be acceptable levels, and evaluation D was considered to be unacceptable levels.
  • the amount of RuO 4 gas generated was measured using ICP-OES. 5 mL of the dry etching residue removal solution was placed in a sealed container, and one 10 ⁇ 20 mm ruthenium film having a thickness of 120 nm was immersed at 30° C. until all of the ruthenium was dissolved. Thereafter, air was flowed into the sealed container, and the gas phase in the sealed container was bubbled into a container containing an absorbing solution (1 mol/L NaOH), and the RuO 4 gas generated during immersion was trapped in the absorbing solution.
  • the storage stability evaluation of the oxidizing agent in the residue removal solution was measured using an ultraviolet-visible spectrophotometer (UV-2600, manufactured by Shimadzu Corporation). 5 L of the dry etching residue removal solution was prepared in a light-shielding pure bottle (manufactured by Kodama Resin Industry Co., Ltd., PFA container 5 L) and stored at 25°C while being shielded from light. Thereafter, the oxidizing agent concentration in the dry etching residue removal solution was periodically measured for 6 months using an ultraviolet-visible spectrophotometer (UV-2600, manufactured by Shimadzu Corporation).
  • UV-2600 ultraviolet-visible spectrophotometer
  • the oxidizing agent concentration immediately after production was set to 100%, and the oxidizing agent concentration in the dry etching residue removal solution after 6 months was evaluated according to the following criteria. In both cases, evaluations A to C were considered to be acceptable levels, and evaluation D was considered to be unacceptable levels.
  • a rotor (AsOne, total length 30 mm x diameter 8 mm) was placed in a three-neck flask, a thermometer protection tube (Cosmos Bead, bottom-sealed type) and a thermometer were placed in one opening, a chlorine gas cylinder and a nitrogen gas cylinder were connected to the other opening, and the tip of a PFA tube (Flon Industries, F-8011-02) that was connected to a state in which chlorine gas/nitrogen gas could be switched at will was immersed in the bottom of the solution, and the remaining opening was connected to a gas washing bottle (AsOne, gas washing bottle, model number 2450/500) filled with a 5% by mass aqueous sodium hydroxide solution.
  • a gas washing bottle (AsOne, gas washing bottle, model number 2450/500) filled with a 5% by mass aqueous sodium hydroxide solution.
  • nitrogen gas with a carbon dioxide concentration of less than 1 ppm was flowed from the PFA tube at 0.289 Pa ⁇ m 3 /sec (at 0°C) for 20 minutes to expel carbon dioxide from the gas phase.
  • the carbon dioxide concentration in the gas phase was 1 ppm or less.
  • a magnetic stirrer (AsOne Corp., C-MAG HS10) was placed at the bottom of the three-neck flask and rotated and stirred at 300 rpm, and while the outer periphery of the three-neck flask was cooled with ice water, chlorine gas (Fujiox Corp., specification purity 99.4%) was supplied at 0.059 Pa ⁇ m 3 /sec (at 0°C) for 180 minutes to obtain a mixed solution of tetramethylammonium hypochlorite aqueous solution (oxidizing agent; equivalent to 3.51% by mass, 0.28 mol/L) and tetramethylammonium hydroxide (equivalent to 0.09% by mass, 0.0097 mol/L).
  • oxidizing agent equivalent to 3.51% by mass, 0.28 mol/L
  • tetramethylammonium hydroxide equivalent to 0.09% by mass, 0.0097 mol/L
  • the liquid temperature during the reaction was 11°C.
  • 0.1 g of sodium hydroxide aqueous solution (0.1 mol/L, Wako Pure Chemical Industries, Ltd.) was weighed into a 100 ml PFA bottle (AsOne, ACPFA100-N) and diluted to 100 ml.
  • 0.1 g of the diluted solution obtained by the above operation was weighed into a 100 ml PFA bottle (AsOne, ACPFA100-N) and diluted to 100 ml. In this way, a metal-containing liquid was obtained.
  • the tetramethylammonium hypochlorite solution obtained by the above operation, ultrapure water, onium salt, tetramethylammonium hydroxide (25% by mass, manufactured by Tokuyama Corporation), hydrochloric acid, and the metal-containing liquid obtained by the above operation were added and mixed to the concentrations shown in Tables 1 to 3 to obtain residue removing solutions having the compositions shown in Examples 19 to 29 and 40 to 42.
  • the metals contained in the residue removing solution are those shown in the metals contained in the dry etching residue removing solution, and the metal concentrations in the residue removing solution are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solution.
  • Examples 2 to 12 and 36 to 38 were also manufactured and evaluated in the same manner.
  • the metals contained in the residue removal solution are the metals described in the metals contained in the dry etching residue removal solution, and the metal concentration in the residue removal solution is the concentration calculated from the total content of Mg, Ca, Na, and K contained in the residue removal solution.
  • the metals contained in the residue removing solution are the metals shown in the metals contained in the dry etching residue removing solution, and the metal concentrations in the residue removing solution are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solution.
  • Commercially available sodium chlorite was added to ultrapure water to obtain a sodium chlorite solution.
  • This sodium chlorite solution was passed through an ion exchange resin that had been ion-exchanged to a tetramethylammonium type, and the sodium ions were replaced with tetramethylammonium ions to obtain a tetramethylammonium chlorite solution.
  • the metals contained in the residue removing solutions are the metals shown in the metals contained in the dry etching residue removing solutions, and the metal concentrations in the residue removing solutions are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solutions.
  • the tetramethylammonium hypochlorite solution obtained by the above operation was mixed with equimolar tetramethylammonium bromide to obtain a tetramethylammonium hypobromite solution.
  • the tetramethylammonium hypochlorite solution obtained by the above operation, the tetramethylammonium bromite solution, the tetramethylammonium chlorate solution, the onium salt, the tetramethylammonium hydroxide (25% by mass, manufactured by Tokuyama Corporation), the hydrochloric acid, and the metal-containing solution obtained by the above operation were added to the tetramethylammonium hypobromite solution to the concentrations described in Table 4, and the residue-removing solution having the composition described in Examples 44 to 46 was obtained.
  • the metals contained in the residue-removing solution are the metals described in the metals contained in the dry etching residue-removing solution, and the metal concentration in the residue-removing solution is the concentration calculated from the total content of Mg, Ca, Na, and K contained in the residue-removing solution.
  • the amount of metal was measured using a triple quadrupole inductively coupled plasma mass spectrometer (ICP-8900, manufactured by Agilent Technologies). A calibration curve was created using standard elemental solutions for ICP analysis containing Mg, Ca, Na, K, Fe, Cr, Ni, Zn, Cu, and Al, and the metal concentration in the treatment solution was measured.
  • ICP-8900 triple quadrupole inductively coupled plasma mass spectrometer

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Abstract

Provided is a dry etching residue removing solution containing: at least one oxidizer selected from the group consisting of hypobromite ions, bromate ions, bromite ions, hypochlorite ions, chlorate ions, and chlorite ions; at least one metal selected from the group consisting of Mg, Ca, Na, and K; and water, wherein the pH of the residue removing solution is 9.5-14 at 25 °C, and the total content of Mg, Ca, Na, and K in the dry etching residue removing solution is 0.01-1,000 ppt.

Description

ドライエッチング残渣除去液Dry etching residue remover
　本発明は、半導体デバイスの製造工程において、ドライエッチング後の残渣を除去するための残渣除去液に関する。 The present invention relates to a residue removal solution for removing residues after dry etching in the manufacturing process of semiconductor devices.
　半導体デバイス中には、トランジスタが発する電気信号を外部に取り出す目的で、配線層が形成されている。半導体デバイスは年々微細化が進んでおり、エレクトロマイグレーション耐性が低い又は抵抗値が高い材料を用いた場合、半導体デバイスの信頼性の低下や、高速動作の阻害を招く。そこで、配線材料としては、エレクトロマイグレーション耐性が高く、抵抗値の低い材料が所望されている。
　このような材料としては、例えば、これまで、アルミニウムや銅が使用されており、最近では、タングステン、コバルト、モリブデン、ルテニウムなどが検討されている。半導体デバイスへ配線層を形成する場合、配線材料を加工する工程が含まれるが、この工程はドライ又はウェットのエッチングが用いられる。 In semiconductor devices, wiring layers are formed for the purpose of extracting electrical signals generated by transistors to the outside. Semiconductor devices are becoming finer year by year, and if a material with low electromigration resistance or high resistance is used, it will lead to a decrease in reliability of the semiconductor device and an impairment of high-speed operation. Therefore, materials with high electromigration resistance and low resistance are desired as wiring materials.
For example, aluminum and copper have been used so far as such materials, and recently, tungsten, cobalt, molybdenum, ruthenium, etc. are being considered. Forming a wiring layer on a semiconductor device includes a process of processing the wiring material, and this process uses dry or wet etching.
　前述の配線材料がルテニウムであり、ルテニウムをアルカリ性条件下でウェットエッチングする場合、ルテニウムは、例えばＲｕＯ４ －やＲｕＯ４ ２－として残渣除去液中に溶解する。ＲｕＯ４ －やＲｕＯ４ ２－は、残渣除去液中でＲｕＯ４へと変化し、その一部がガス化して気相へ放出される。ＲｕＯ４は強酸化性であるため人体に有害であるばかりでなく、容易に還元されてＲｕＯ２パーティクルを生じる。一般的に、パーティクルは歩留まり低下を招くため半導体形成工程において非常に問題となる。このような背景から、ＲｕＯ４ガスの発生を抑制する事は非常に重要となる。
　特許文献１には、良好なエッチング速度と、その速度の安定性を示し、かつＲｕＯ４ガスの発生を抑制可能な、次亜塩素酸イオンを含む半導体ウエハの残渣除去液が提案されている。
　特許文献２には、良好なエッチング速度と、その速度の安定性を有し、かつＲｕＯ４ガスの発生を抑制可能な、次亜臭素酸イオンを含む半導体ウエハの残渣除去液が提案されている。 When the wiring material is ruthenium and ruthenium is wet etched under alkaline conditions, ruthenium dissolves in the residue remover as, for example, RuO 4 - or RuO 4 2- . RuO 4 - or RuO 4 2- changes to RuO 4 in the residue remover, and a part of it gasifies and is released into the gas phase. RuO 4 is not only harmful to the human body because of its strong oxidizing properties, but is also easily reduced to produce RuO 2 particles. In general, particles are a major problem in the semiconductor formation process because they cause a decrease in yield. In this context, it is very important to suppress the generation of RuO 4 gas.
Patent Document 1 proposes a semiconductor wafer residue remover solution that contains hypochlorite ions and exhibits a good etching rate and stability of the rate, and is also capable of suppressing the generation of RuO 4 gas.
Patent Document 2 proposes a semiconductor wafer residue remover solution that contains hypobromite ions and has a good etching rate and a stable etching rate, and is also capable of suppressing the generation of RuO4 gas.
国際公開第２０１９／１４２７８８号International Publication No. 2019/142788 国際公開第２０２１／０５９６６６号International Publication No. 2021/059666
　配線材料をドライエッチングする場合、ドライエッチングを行うことで生じた副生成物であるエッチング残渣が生じることがある。エッチング残渣等の不純物は製造される半導体デバイスの歩留まり低下、信頼性低下などの悪影響を与える可能性があることが知られている。エッチング残渣はウェットエッチング液により除去されるが、従来のウェットエッチング液は、該ウェットエッチング液中に含まれる酸化剤の保存安定性が悪いことが問題であった。
　したがって、本発明の目的は高いエッチング残渣を除去する効果を有し、さらに、液中で酸化剤が良好な保存安定性を有する、エッチング残渣除去液を提供することにある。 When dry etching wiring materials, etching residues, which are by-products of the dry etching, may be generated. It is known that impurities such as etching residues may have adverse effects such as a decrease in yield and reliability of the semiconductor devices manufactured. The etching residues are removed by wet etching solutions, but the problem with conventional wet etching solutions is that the oxidizing agent contained in the wet etching solutions has poor storage stability.
Therefore, an object of the present invention is to provide an etching residue removing solution which has a high etching residue removing effect and further has an oxidizing agent with good storage stability in the solution.
　本発明者らは、上記課題を解決するために鋭意検討を行った。
すなわち、本発明の構成は以下の通りである。 The present inventors have conducted extensive research to solve the above problems.
That is, the present invention is configured as follows.
項１　ドライエッチング後の残渣を除去するためのドライエッチング残渣除去液であって
　次亜臭素酸イオン、亜臭素酸イオン、臭素酸イオン、次亜塩素酸イオン、亜塩素酸イオン及び塩素酸イオンから成る群から選択される１種以上の酸化剤、Ｍｇ、Ｃａ、Ｎａ、及びＫから成る群から選択される１種以上の金属、並びに、水を含有し、
　前記残渣除去液のｐＨが、２５℃で９.５以上１４以下であり、前記ドライエッチング残渣除去液において、Ｍｇ、Ｃａ、Ｎａ、及びＫの合計含有量が０．０１ｐｐｔ以上１０００ｐｐｔ以下である、ドライエッチング残渣除去液。
項２　前記酸化剤の濃度が、０．０００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下である、項１に記載のドライエッチング残渣除去液。
項３　前記酸化剤が次亜塩素酸イオンであり、次亜塩素酸イオンの濃度が０．００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下である、項１に記載のドライエッチング残渣除去液。
項４　前記酸化剤が次亜臭素酸イオンであり、次亜臭素酸イオンの濃度が０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下である、項２に記載のドライエッチング残渣除去液。
項５　さらにオニウムイオンを含み、且つ前記残渣除去液の表面張力が６０ｍＮ／ｍ以上７５ｍＮ／ｍ以下である、項１～４のいずれか１項に記載のドライエッチング残渣除去液。
項６　前記オニウムイオンが、式（１）～式（６）で示されるオニウムイオンからなる群から選択される１種以上である、項５に記載のドライエッチング残渣除去液。
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000011
Figure JPOXMLDOC01-appb-C000012
（式（１）～式（６）中、
　Ｒ１、Ｒ２、Ｒ３、Ｒ４、Ｒ５、Ｒ６は独立して、炭素数２～９のアルキル基、アリル基、炭素数１～９のアルキル基を有するアラルキル基、又はアリール基である。また、アラルキル基中のアリール基及びアリール基の環において少なくとも１つの水素は、フッ素、塩素、炭素数１～９のアルキル基、炭素数２～９のアルケニル基、炭素数１～９のアルコキシ基、又は炭素数２～９のアルケニルオキシ基で置き換えられてもよく、これらの基において、少なくとも１つの水素は、フッ素、塩素、臭素、又はヨウ素で置き換えられてもよい。
　Ａはアンモニウムイオン、又はホスホニウムイオンである。
　Ｚは、窒素、硫黄、酸素原子を含んでもよい芳香族基又は脂環式基であり、該芳香族基又は該脂環式基において、炭素又は窒素は、塩素、臭素、フッ素、ヨウ素、少なくとも１つの炭素数１～９のアルキル基、少なくとも１つの炭素数２～９のアルケニルオキシ基、少なくとも１つの炭素数１～９のアルキル基で置換されてもよい芳香族基、又は、少なくとも１つの炭素数１～９のアルキル基で置換されてもよい脂環式基を有していてもよい。
　Ｒは塩素、臭素、フッ素、ヨウ素、炭素数１～９のアルキル基、アリル基、少なくとも１つの炭素数１～９のアルキル基で置換されてもよい芳香族基、又は少なくとも１つの炭素数１～９のアルキル基で置換されてもよい脂環式基である。ｎは１又は２の整数であり、Ｒの数を示す。ｎが２の場合、Ｒは同一又は異なっていてもよく、環を形成してもよい。
　ａは１～１０の整数である。）
項７　前記オニウムイオンの濃度が１質量ｐｐｍ以上１０，０００質量ｐｐｍ以下である、項５または６に記載のドライエッチング残渣除去液。
項８　項１～７のいずれか１項に記載のドライエッチング残渣除去液と半導体ウエハを接触させる工程を含む、半導体ウエハのドライエッチング残渣除去方法。
項９　半導体ウエハをドライエッチングする工程、及び、項１～７のいずれか１項に記載のドライエッチング残渣除去液によりドライエッチング残渣を除去する工程を含む、半導体デバイスの製造方法。
項１０　前記半導体ウエハがルテニウム系金属を有する半導体ウエハであることを特徴とする、項９に記載の半導体デバイスの製造方法。 Item 1. A dry etching residue removal solution for removing residues after dry etching, comprising one or more oxidizing agents selected from the group consisting of hypobromite ions, bromite ions, bromate ions, hypochlorite ions, chlorite ions, and chlorate ions, one or more metals selected from the group consisting of Mg, Ca, Na, and K, and water;
The dry etching residue removing solution has a pH of 9.5 or more and 14 or less at 25° C., and the total content of Mg, Ca, Na, and K in the dry etching residue removing solution is 0.01 ppt or more and 1000 ppt or less.
Item 2. The dry etching residue removing solution according to Item 1, wherein the concentration of the oxidizing agent is 0.0001 mol/L or more and 0.40 mol/L or less.
Item 3. The dry etching residue removing solution according to Item 1, wherein the oxidizing agent is hypochlorite ions, and the concentration of the hypochlorite ions is 0.001 mol/L or more and 0.40 mol/L or less.
Item 4. The dry etching residue removing solution according to Item 2, wherein the oxidizing agent is hypobromite ions, and the concentration of the hypobromite ions is 0.001 mol/L or more and 0.20 mol/L or less.
Item 5. The dry etching residue removing solution according to any one of Items 1 to 4, further comprising an onium ion, and the surface tension of the residue removing solution is 60 mN/m or more and 75 mN/m or less.
Item 6. The dry etching residue removing solution according to Item 5, wherein the onium ion is one or more selected from the group consisting of onium ions represented by formulas (1) to (6).
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000011
Figure JPOXMLDOC01-appb-C000012
(In formula (1) to formula (6),
R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently an alkyl group having 2 to 9 carbon atoms, an allyl group, an aralkyl group having an alkyl group having 1 to 9 carbon atoms, or an aryl group. In addition, at least one hydrogen atom in the aryl group in the aralkyl group and in the ring of the aryl group may be replaced by fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkenyloxy group having 2 to 9 carbon atoms, and in these groups, at least one hydrogen atom may be replaced by fluorine, chlorine, bromine or iodine.
A is an ammonium ion or a phosphonium ion.
Z is an aromatic group or an alicyclic group which may contain nitrogen, sulfur or oxygen atoms, and in the aromatic group or the alicyclic group, carbon or nitrogen may have chlorine, bromine, fluorine, iodine, at least one alkyl group having 1 to 9 carbon atoms, at least one alkenyloxy group having 2 to 9 carbon atoms, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
R is chlorine, bromine, fluorine, iodine, an alkyl group having 1 to 9 carbon atoms, an allyl group, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms. n is an integer of 1 or 2 and indicates the number of R. When n is 2, R may be the same or different and may form a ring.
a is an integer from 1 to 10.
Item 7. The dry etching residue removing solution according to Item 5 or 6, wherein the onium ion has a concentration of 1 ppm by mass or more and 10,000 ppm by mass or less.
Item 8. A method for removing dry etching residues from a semiconductor wafer, comprising the step of contacting the semiconductor wafer with the dry etching residue removing solution according to any one of items 1 to 7.
Item 9. A method for manufacturing a semiconductor device, comprising the steps of dry etching a semiconductor wafer and removing dry etching residues with the dry etching residue removing solution according to any one of Items 1 to 7.
Item 10. The method for producing a semiconductor device according to item 9, wherein the semiconductor wafer is a semiconductor wafer containing a ruthenium-based metal.
　本発明によれば、半導体デバイスの製造工程においてドライエッチングによる基板上の残渣を高効率で除去でき、保存安定性に優れ、さらに、後述する被処理物の表面の平滑性を保持するドライエッチング残渣除去液を提供できる。 The present invention provides a dry etching residue removal solution that can remove residues on a substrate caused by dry etching in the manufacturing process of semiconductor devices with high efficiency, has excellent storage stability, and maintains the smoothness of the surface of the workpiece, as described below.
　以下、本発明について詳細に説明する。以下の説明は、本発明の一例（代表例）であり、本発明はこれらに限定されるものではない。また、本発明は、その要旨を逸脱しない範囲内で任意に変更して実施することができる。本発明のドライエッチング残渣除去液は、後述する特定金属を含有する組成物であることを特徴としている。また、本発明中でドライエッチング残渣除去液（すなわち、ドライエッチング後の残渣を除去するために用いる薬液）は、残渣除去液とも記載する。 The present invention will be described in detail below. The following description is one example (representative example) of the present invention, and the present invention is not limited thereto. Furthermore, the present invention can be practiced with any modifications within the scope of the gist of the invention. The dry etching residue removal solution of the present invention is characterized by being a composition containing a specific metal, which will be described later. Furthermore, in the present invention, the dry etching residue removal solution (i.e., the chemical solution used to remove residues after dry etching) is also referred to as the residue removal solution.
（被処理物）
　本発明の残渣除去液が適用される被処理物（エッチングの対象物）は、遷移金属を含む半導体ウエハである。被処理物の製造方法は特に限定されない。例えば、被処理物は次のような方法により得られる。シリコンなどの基板に酸化処理を行い、基板上に酸化シリコン膜を形成し、その上に層間絶縁膜を成膜する。さらに、層間絶縁膜上にフォトレジスト膜を成膜し、層間絶縁膜にビアホールを形成する。形成されたビアホールに金属膜を成膜する。 (Item to be processed)
The workpiece (etching target) to which the residue removing solution of the present invention is applied is a semiconductor wafer containing a transition metal. The manufacturing method of the workpiece is not particularly limited. For example, the workpiece is obtained by the following method. A substrate such as silicon is subjected to an oxidation treatment to form a silicon oxide film on the substrate, and an interlayer insulating film is formed thereon. Furthermore, a photoresist film is formed on the interlayer insulating film, and a via hole is formed in the interlayer insulating film. A metal film is formed in the formed via hole.
　遷移金属の一例を挙げれば、タンタル、シリコン、銅、ハフニウム、ジルコニウム、アルミニウム、バナジウム、コバルト、ニッケル、マンガン、金、ロジウム、パラジウム、チタン、タングステン、モリブデン、白金、イリジウム、ルテニウムなどが挙げられ、これらの酸化物、窒化物、シリサイドを含んでいてもよい。エレクトロマイグレーション耐性が高く、抵抗値が低いという点から、タングステン、コバルト、モリブデン、またはルテニウムが好ましく、ルテニウムが特に好ましい。
　被処理物に含まれる金属膜はいかなる方法により形成されていてもよく、例えばＣＶＤ、ＡＬＤ、ＰＶＤ、スパッタ、めっき等を利用できる。 Examples of transition metals include tantalum, silicon, copper, hafnium, zirconium, aluminum, vanadium, cobalt, nickel, manganese, gold, rhodium, palladium, titanium, tungsten, molybdenum, platinum, iridium, and ruthenium, and may contain oxides, nitrides, and silicides thereof. In terms of high electromigration resistance and low resistance value, tungsten, cobalt, molybdenum, and ruthenium are preferred, and ruthenium is particularly preferred.
The metal film contained in the workpiece may be formed by any method, such as CVD, ALD, PVD, sputtering, plating, and the like.
（ドライエッチング残渣）
　ドライエッチング残渣とは、ドライエッチングにより発生する副生成物で、前述の被処理物の一部である。例えば、Ｓｉ含有残渣物、金属含有残渣物、及び、フォトレジスト由来の有機物含有残渣物等が挙げられる。 (Dry etching residue)
Dry etching residues are by-products generated by dry etching and are part of the above-mentioned processed object. Examples of the residues include Si-containing residues, metal-containing residues, and organic matter-containing residues derived from photoresist.
（ドライエッチング残渣除去液）
　本発明のドライエッチング残渣除去液（残渣除去液）とは、ドライエッチングを行う事により基板上に生じた残渣を、除去するために用いる薬液である。本発明の残渣除去液は、次亜臭素酸イオン、亜臭素酸イオン、次亜塩素酸イオン、及び塩素酸イオンから成る群から選択される１種以上の酸化剤、後述する特定金属、及び、水を含む。
　次亜塩素酸イオン、次亜臭素酸イオンは強酸化性を有する酸化剤であり、次亜塩素酸イオン、または次亜臭素酸イオン等を含む本発明の残渣除去液は、アルカリ性条件下で遷移金属を高速にエッチングすることができる。
　被処理物がルテニウムである場合は、エッチング時のＲｕＯ４ガス発生を抑制することができる。これにより、単位時間当たりのウエハ処理効率が向上するだけでなく、ＲｕＯ２パーティクルによる歩留まり低下を抑制し、かつ、人体に安全な処理が可能になり、製造コストと安全性の両立が達成される。さらに、ｐＨ、酸化剤の種類及び濃度を適切に選択することにより、ＲｕＯ４ガス発生を抑制しながら、安定したエッチング速度でルテニウムをエッチングできる。 (Dry etching residue remover)
The dry etching residue removing solution (residue removing solution) of the present invention is a chemical solution used to remove residues generated on a substrate by performing dry etching. The residue removing solution of the present invention contains one or more oxidizing agents selected from the group consisting of hypobromite ions, bromite ions, hypochlorite ions, and chlorate ions, a specific metal described below, and water.
Hypochlorite ions and hypobromite ions are oxidizing agents having strong oxidizing properties, and the residue removal solution of the present invention containing hypochlorite ions or hypobromite ions or the like can rapidly etch transition metals under alkaline conditions.
When the object to be treated is ruthenium, the generation of RuO4 gas during etching can be suppressed. This not only improves the wafer processing efficiency per unit time, but also suppresses the yield reduction caused by RuO2 particles, and enables safe processing for the human body, achieving both manufacturing cost and safety. Furthermore, by appropriately selecting the pH and the type and concentration of the oxidizing agent, ruthenium can be etched at a stable etching rate while suppressing the generation of RuO4 gas.
（酸化剤）
　本発明のドライエッチング残渣除去液に酸化剤を含ませる事で、ドライエッチング残渣に含まれる金属を除去する機能を付加する事が可能となる。さらに、アルカリ性のドライエッチング残渣除去液中に酸化剤を含むことで有機物含有残渣物を分解し剥離する効果を有し、また、アルカリ性水溶液中では、非溶解性の無機物含有残渣物と被処理物の表面電位は負に帯電するため、静電反発の作用から、非溶解性の無機物含有残渣物の基板等への再付着を妨げる効果を有する。
　酸化剤の種類は特に制限されないが、例えば、過酸化水素、オゾン、次亜塩素酸、亜塩素酸、塩素酸、過塩素酸、次亜臭素酸、亜臭素酸、臭素酸、過臭素酸、次亜ヨウ素酸、亜ヨウ素酸、ヨウ素酸、過ヨウ素酸（オルト過ヨウ素酸、メタ過ヨウ素酸）、これらの塩、およびこれらの塩が解離して生ずるイオン、さらに、過酸化水素、オゾン、フッ素、塩素、臭素、ヨウ素、過マンガン酸塩、クロム酸塩、二クロム酸塩、およびセリウム塩からなる群から選択される一種以上が挙げられる。中でも、酸化力の強さ、安定性、半導体用途に好適に用いられる事から、次亜臭素酸イオン、亜臭素酸イオン、臭素酸イオン、次亜塩素酸イオン、亜塩素酸イオン、塩素酸イオン、次亜ヨウ素酸イオン、亜ヨウ素酸イオン、ヨウ素酸イオン、過ヨウ素酸イオン、が好ましく、次亜臭素酸イオン、臭素酸イオン、亜臭素酸イオン、次亜塩素酸イオン、塩素酸イオン、亜塩素酸イオンがより好ましく、次亜臭素酸イオン、亜臭素酸イオン、次亜塩素酸イオン、塩素酸イオンがさらに好ましい。 (Oxidant)
By adding an oxidizing agent to the dry etching residue removing solution of the present invention, it is possible to add a function of removing metals contained in dry etching residues. Furthermore, by adding an oxidizing agent to an alkaline dry etching residue removing solution, it has the effect of decomposing and peeling off organic matter-containing residues, and in an alkaline aqueous solution, the surface potential of the insoluble inorganic matter-containing residues and the treated object is negatively charged, so that the electrostatic repulsion effect prevents the insoluble inorganic matter-containing residues from reattaching to a substrate or the like.
The type of oxidizing agent is not particularly limited, and examples thereof include hydrogen peroxide, ozone, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodous acid, iodous acid, iodic acid, periodic acid (orthoperiodic acid, metaperiodic acid), salts thereof, and ions generated by dissociation of these salts, as well as one or more selected from the group consisting of hydrogen peroxide, ozone, fluorine, chlorine, bromine, iodine, permanganate, chromate, dichromate, and cerium salts. Among these, hypobromite ion, bromite ion, bromate ion, hypochlorite ion, chlorite ion, chlorate ion, hypoiodite ion, iodite ion, iodate ion, and periodate ion are preferred because of their strong oxidizing power, stability, and suitability for use in semiconductor applications, and hypobromite ion, bromate ion, bromite ion, hypochlorite ion, chlorate ion, and chlorite ion are more preferred, and hypobromite ion, bromite ion, hypochlorite ion, and chlorate ion are even more preferred.
　本発明の残渣除去液における酸化剤の濃度は、本発明の目的を逸脱しない限り特に制限されることはないが、０．０００１ｍｏｌ／Ｌ以上０．５０ｍｏｌ／Ｌ以下を挙げることができ、好ましくは、０．０００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下であることが好ましい。０．０００１ｍｏｌ／Ｌ未満ではドライエッチング残渣除去効率が小さく、実用性が低い。一方、０．５０ｍｏｌ／Ｌを超える場合は、酸化剤の分解が生じやすくなるため、ドライエッチング残渣除去効率が安定しにくくなることがある。 The concentration of the oxidizing agent in the residue removal solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but may be from 0.0001 mol/L to 0.50 mol/L, and preferably from 0.0001 mol/L to 0.40 mol/L. If the concentration is less than 0.0001 mol/L, the dry etching residue removal efficiency is low and the practicality is low. On the other hand, if the concentration exceeds 0.50 mol/L, the oxidizing agent is more likely to decompose, and the dry etching residue removal efficiency may become unstable.
　本発明の残渣除去液に含まれる酸化剤は、１種であっても、複数種であってもよい。複数種含まれる場合、１種目とは異なる２種目に含まれる酸化剤の種類は特に制限されないが、例えば、過酸化水素、オゾン、次亜塩素酸、亜塩素酸、塩素酸、過塩素酸、次亜臭素酸、亜臭素酸、臭素酸、過臭素酸、次亜ヨウ素酸、亜ヨウ素酸、ヨウ素酸、過ヨウ素酸、これらの塩、およびこれらの塩が解離して生ずるイオン、さらに、過酸化水素、オゾン、フッ素、塩素、臭素、ヨウ素、過マンガン酸塩、クロム酸塩、二クロム酸塩、およびセリウム塩からなる群から選択される一種以上が挙げられる。なお、１種目の酸化剤としては、次亜臭素酸イオンまたは次亜塩素酸イオンを挙げることができる。
　複数種の酸化剤が含まれる事で、残渣除去率が安定化したり、残渣除去液を再利用する際の安定性が向上する場合がある。例えば、１種目の酸化剤として次亜臭素酸イオンが含まれる場合、金属のエッチングに消費された次亜臭素酸イオンは、酸化力を失って臭化物イオンへと変化する。この場合、臭化物イオンへと変化した量が多ければ多いほど、残渣除去能は低下する。半導体ウエハの製造所では、コスト削減の観点から、処理液を循環して再利用する事が一般的だが、処理液の再利用により残渣除去能が低下すると、半導体ウエハを安定して製造する事が困難となる。一方、残渣除去液中に酸化剤が複数種含まれる場合、例えば、次亜臭素酸イオンに加えて次亜塩素酸イオンが含まれると、酸化力を失った臭化物イオンは、次亜塩素酸イオンにより酸化される事で次亜臭素酸イオンへ変化する。このため、残渣除去液中の次亜臭素酸イオン濃度の低下を抑制する事が可能であり、残渣除去液を再利用した場合でもエッチング速度の低下は生じにくくなる。また、本発明の残渣除去液に含まれる酸化剤が複数種であるとき、酸化剤の合計濃度が０．０００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下であることが望ましい。 The oxidizing agent contained in the residue removing solution of the present invention may be one or more kinds. When multiple kinds are contained, the type of the oxidizing agent contained in the second kind different from the first kind is not particularly limited, but for example, hydrogen peroxide, ozone, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodous acid, iodous acid, iodic acid, periodic acid, salts thereof, and ions generated by dissociation of these salts, and further, one or more kinds selected from the group consisting of hydrogen peroxide, ozone, fluorine, chlorine, bromine, iodine, permanganate, chromate, dichromate, and cerium salt can be mentioned. The first kind of oxidizing agent can be hypobromite ion or hypochlorite ion.
By including multiple types of oxidizing agents, the residue removal rate may be stabilized, and the stability when reusing the residue removal liquid may be improved. For example, when hypobromite ions are included as the first type of oxidizing agent, the hypobromite ions consumed in etching the metal lose their oxidizing power and change to bromide ions. In this case, the more the amount of bromide ions that change to bromide ions, the lower the residue removal ability. In semiconductor wafer manufacturing plants, it is common to circulate and reuse the processing liquid from the viewpoint of cost reduction, but if the residue removal ability decreases due to the reuse of the processing liquid, it becomes difficult to stably manufacture semiconductor wafers. On the other hand, when multiple types of oxidizing agents are included in the residue removal liquid, for example, when hypochlorite ions are included in addition to hypobromite ions, the bromide ions that have lost their oxidizing power are oxidized by hypochlorite ions and change to hypobromite ions. For this reason, it is possible to suppress the decrease in the concentration of hypobromite ions in the residue removal liquid, and even when the residue removal liquid is reused, the etching rate is less likely to decrease. Furthermore, when the residue removing solution of the present invention contains a plurality of types of oxidizing agents, the total concentration of the oxidizing agents is desirably 0.0001 mol/L or more and 0.40 mol/L or less.
（酸化剤のカウンターカチオン）
　酸化剤のカウンターカチオンとしては、特に制限されないが、金属イオン、または後述するオニウムイオンが好ましい。金属イオンの例としては、カルシウムイオン、ナトリウムイオン、カリウムイオン、マグネシウムイオン、鉄イオン、クロムイオン、ニッケルイオン、亜鉛イオン、銅イオン、アルミニウムイオンなどが挙げられる。半導体製造においては、金属または金属イオンが半導体ウエハ上に残存すると、電気特性や加工形状に異常を発生させる可能性があるためできるだけ含まないことが望ましく、酸化剤のカウンターカチオンとしては、オニウムイオンが好ましい。 (Counter cation of oxidizing agent)
The counter cation of the oxidizing agent is not particularly limited, but is preferably a metal ion or an onium ion described later. Examples of metal ions include calcium ion, sodium ion, potassium ion, magnesium ion, iron ion, chromium ion, nickel ion, zinc ion, copper ion, and aluminum ion. In semiconductor manufacturing, if metal or metal ion remains on the semiconductor wafer, it may cause abnormalities in electrical characteristics and processed shape, so it is desirable to contain as little as possible, and the counter cation of the oxidizing agent is preferably an onium ion.
（次亜臭素酸イオン）
　次亜臭素酸イオンは、残渣除去液中で発生させてもよいし、次亜臭素酸塩として残渣除去液に添加してもよい。ここで言う次亜臭素酸塩とは、次亜臭素酸イオンを含有する塩、または該塩を含む溶液のことである。次亜臭素酸イオン（ＢrО－、ＢrОとも記載）を残渣除去液中で発生させるには、例えば、臭素ガスを残渣除去液に吹き込めばよい。この場合、次亜臭素酸イオンを効率よく発生させる観点から、残渣除去液は５０℃以下であることが好ましい。残渣除去液が５０℃以下であれば効率よく次亜臭素酸イオンを発生できるだけでなく、発生した次亜臭素酸イオンを安定にドライエッチング残渣除去に用いることができる。さらに、臭素をより多く残渣除去液に溶解させるためには、残渣除去液の温度は３０℃以下であることがより好ましく、２５℃以下であることが最も好ましい。残渣除去液の温度の下限は特に制限されないが、残渣除去液が凍結しないことが好ましい。したがって、残渣除去液は－３５℃以上であることが好ましく、－１５℃以上であることがより好ましく、０℃以上であることが最も好ましい。該臭素ガスを吹き込む残渣除去液のｐＨは特に制限されないが、残渣除去液のｐＨがアルカリ性であれば、次亜臭素酸イオンの生成後、すぐにドライエッチング残渣除去に供することができる。 (hypobromite ion)
The hypobromite ions may be generated in the residue removal liquid, or may be added to the residue removal liquid as hypobromite. The hypobromite salt referred to here is a salt containing hypobromite ions, or a solution containing the salt. To generate hypobromite ions (also written as BrO - or BrO) in the residue removal liquid, for example, bromine gas may be blown into the residue removal liquid. In this case, from the viewpoint of efficiently generating hypobromite ions, the residue removal liquid is preferably at 50° C. or less. If the residue removal liquid is at 50° C. or less, not only can hypobromite ions be efficiently generated, but the generated hypobromite ions can be stably used for removing dry etching residues. Furthermore, in order to dissolve as much bromine as possible in the residue removal liquid, the temperature of the residue removal liquid is more preferably at 30° C. or less, and most preferably at 25° C. or less. There is no particular limit on the lower limit of the temperature of the residue removal liquid, but it is preferable that the residue removal liquid does not freeze. Therefore, the temperature of the residue removal solution is preferably −35° C. or higher, more preferably −15° C. or higher, and most preferably 0° C. or higher. There are no particular limitations on the pH of the residue removal solution into which the bromine gas is blown, but if the pH of the residue removal solution is alkaline, it can be used to remove dry etching residues immediately after hypobromite ions are generated.
　さらに、残渣除去液に臭素ガスを吹き込むことで次亜臭素酸イオンを発生させる場合、残渣除去液に臭化物イオン（Ｂｒ－）が含まれていると、臭素ガス（Ｂｒ２）の溶解性が向上する。残渣除去液に溶解したＢｒ２がＢｒ－やＢｒ３ －と反応し、Ｂｒ３ －やＢｒ５ －のような錯イオンを形成し、残渣除去液中で安定化するためである。Ｂｒ２、Ｂｒ－、Ｂｒ３ －、Ｂｒ５ －等を多く含む残渣除去液は、次亜臭素酸イオンをより多く生成できるため、本発明の残渣除去液として好適に用いることができる。 Furthermore, when hypobromite ions are generated by blowing bromine gas into the residue removal liquid, the solubility of bromine gas (Br 2 ) is improved if the residue removal liquid contains bromide ions (Br - ). This is because Br 2 dissolved in the residue removal liquid reacts with Br - or Br 3 - to form complex ions such as Br 3 - or Br 5 - , which are stabilized in the residue removal liquid. A residue removal liquid containing a large amount of Br 2 , Br - , Br 3 - , Br 5 - or the like can generate more hypobromite ions, and is therefore suitable for use as the residue removal liquid of the present invention.
　また、酸化剤により臭素含有化合物を酸化することで、残渣除去液中で次亜臭素酸イオンを作り出すこともできる。
　次亜臭素酸イオンを化合物として残渣除去液に添加するには、次亜臭素酸、臭素水、および／または次亜臭素酸塩を加えればよい。次亜臭素酸塩としては、次亜臭素酸ナトリウム、次亜臭素酸カリウム、次亜臭素酸テトラアルキルアンモニウムが好適であり、半導体製造において問題となる金属イオンを実質的に含まないという点で、次亜臭素酸又は次亜臭素酸テトラアルキルアンモニウムがさらに好適である。
　前述の次亜臭素酸テトラアルキルアンモニウムは、水酸化テトラアルキルアンモニウム溶液に臭素ガスを通じることで容易に得られる。また、次亜臭素酸と水酸化テトラアルキルアンモニウム溶液を混合することでも得られる。さらに、次亜臭素酸ナトリウムなどの次亜臭素酸塩に含まれるカチオンを、イオン交換樹脂を用いてテトラアルキルアンモニウムイオンに置換することでも次亜臭素酸テトラアルキルアンモニウムを得ることができる。 In addition, hypobromite ions can be produced in the residue removal solution by oxidizing bromine-containing compounds with an oxidizing agent.
To add hypobromite ions as a compound to the residue removal solution, hypobromite, bromine water, and/or hypobromite may be added. As hypobromite, sodium hypobromite, potassium hypobromite, and tetraalkylammonium hypobromite are preferable, and hypobromite or tetraalkylammonium hypobromite are more preferable because they are substantially free of metal ions that are problematic in semiconductor manufacturing.
The above-mentioned tetraalkylammonium hypobromite can be easily obtained by passing bromine gas through a tetraalkylammonium hydroxide solution. It can also be obtained by mixing hypobromous acid with a tetraalkylammonium hydroxide solution. Furthermore, tetraalkylammonium hypobromite can also be obtained by replacing the cations contained in hypobromites such as sodium hypobromite with tetraalkylammonium ions using an ion exchange resin.
　本発明の残渣除去液における前記次亜臭素酸イオンの濃度は、本発明の目的を逸脱しない限り特に制限されることはないが、好ましくは、次亜臭素酸イオンとして０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下である。０．００１ｍｏｌ／Ｌ未満ではドライエッチング残渣除去効率が小さく、実用性が低い。一方、０．２０ｍｏｌ／Ｌを超える場合は、次亜臭素酸イオンの分解が生じやすくなるため、ドライエッチング残渣除去効率が安定しにくくなる。ドライエッチング残渣除去を十分な速度で安定して行うためには、該次亜臭素酸イオンの濃度が０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下であることが好ましく、０．００５ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下であることがさらに好ましく、０．０１ｍｏｌ／Ｌ以上０．１０ｍｏｌ／Ｌ以下であることが最も好ましい。 The concentration of the hypobromite ions in the residue removal solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less in terms of hypobromite ions. If the concentration is less than 0.001 mol/L, the dry etching residue removal efficiency is low and practicality is low. On the other hand, if the concentration exceeds 0.20 mol/L, decomposition of the hypobromite ions is likely to occur, making it difficult to stabilize the dry etching residue removal efficiency. In order to stably remove dry etching residue at a sufficient speed, the concentration of the hypobromite ions is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.005 mol/L or more and 0.20 mol/L or less, and most preferably 0.01 mol/L or more and 0.10 mol/L or less.
　ドライエッチング残渣除去能の低下を緩やかにし、ドライエッチング残渣除去効率を安定させるためには、残渣除去液に含まれる臭素元素１モル中の次亜臭素酸イオンの割合が０．５モルを超えることが好ましい。上記の通り、次亜臭素酸イオンはルテニウムの酸化反応や分解反応により容易にＢｒ－へと変化する。Ｂｒ－は金属含有残渣物をエッチングしないため、残渣除去液中のＢｒ－を速やかに次亜臭素酸イオンへと酸化して、高ドライエッチング残渣除去能を有する化学種（次亜臭素酸イオン；ＢｒＯ－）の濃度を高く保つことが、安定したドライエッチング残渣除去のために重要である。本発明の残渣除去液に含まれる臭素元素１モル中の次亜臭素酸イオンの割合が０．５モルを超えている場合、すなわち、残渣除去液中の全臭素元素のうち半数より多くの臭素元素がＢｒＯ－として存在している場合、ドライエッチング残渣除去能を有する化学種の濃度は十分高いとみなすことができ、ドライエッチング残渣除去効率が安定化する。 In order to slow down the decrease in dry etching residue removal ability and stabilize the dry etching residue removal efficiency, it is preferable that the ratio of hypobromite ions in 1 mole of bromine element contained in the residue removal solution exceeds 0.5 moles. As described above, hypobromite ions are easily converted to Br - by the oxidation reaction or decomposition reaction of ruthenium. Since Br - does not etch metal-containing residues, it is important for stable dry etching residue removal to quickly oxidize Br - in the residue removal solution to hypobromite ions and maintain a high concentration of chemical species (hypobromite ions; BrO - ) having high dry etching residue removal ability. When the ratio of hypobromite ions in 1 mole of bromine element contained in the residue removal solution of the present invention exceeds 0.5 moles, that is, when more than half of the bromine elements of the total bromine elements in the residue removal solution are present as BrO - , the concentration of chemical species having dry etching residue removal ability can be considered to be sufficiently high, and the dry etching residue removal efficiency is stabilized.
　残渣除去液中の次亜臭素酸イオンの濃度は、広く公知の方法を用いて確認することができる。例えば、紫外可視吸光光度法を用いれば、次亜臭素酸イオンに起因する吸収が容易に確認され、その吸収ピーク（残渣除去液のｐＨや次亜臭素酸イオン濃度等に依るが、概ね３３０ｎｍ付近）の強度から次亜臭素酸イオン濃度を求めることができる。さらに、ヨウ素滴定によっても次亜臭素酸イオン濃度を求めることができる。他にも残渣除去液の酸化還元電位（ＯＲＰ）から次亜臭素酸イオン濃度を求めることができる。非接触でありかつ連続測定が可能であるという観点から、紫外可視吸光光度法による測定が最も好ましい。なお、紫外可視吸光光度法により次亜臭素酸イオン濃度を測定する際、他の化学種による吸収がある場合は、スペクトル分割やベースライン補正などのデータ処理や、リファレンスの適切な選択などを行うことで、次亜臭素酸イオン濃度を十分な精度で求めることができる。 The concentration of hypobromite ions in the residue removal solution can be confirmed using widely known methods. For example, by using ultraviolet-visible spectrophotometry, the absorption caused by hypobromite ions can be easily confirmed, and the hypobromite ion concentration can be calculated from the intensity of the absorption peak (approximately around 330 nm, depending on the pH of the residue removal solution and the hypobromite ion concentration, etc.). Furthermore, the hypobromite ion concentration can also be calculated by iodine titration. The hypobromite ion concentration can also be calculated from the oxidation-reduction potential (ORP) of the residue removal solution. Measurement by ultraviolet-visible spectrophotometry is the most preferable from the viewpoint of non-contact and continuous measurement. Note that when measuring the hypobromite ion concentration by ultraviolet-visible spectrophotometry, if there is absorption due to other chemical species, the hypobromite ion concentration can be calculated with sufficient accuracy by performing data processing such as spectrum division and baseline correction, and appropriate selection of a reference.
　（亜臭素酸イオン）
　本発明のドライエッチング残渣除去液が亜臭素酸イオン（ＢｒО２ －、ＢｒО２とも記載）を含む場合、その濃度が０．０００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下であるとき薬液の保存安定性を向上することができる。
　本発明の残渣除去液における前記亜臭素酸イオンの濃度は、本発明の目的を逸脱しない限り特に制限されることはないが、好ましくは、亜臭素酸イオン量として０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下である。０．００１ｍｏｌ／Ｌ未満ではドライエッチング残渣除去効率が小さく、実用性が低い。一方、０．２０ｍｏｌ／Ｌを超える場合は、亜臭素酸イオンの分解が生じやすくなるため、ドライエッチング残渣除去効率が安定しにくくなる。ドライエッチング残渣除去を十分な速度で安定して行うためには、該亜臭素酸イオンの濃度として０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下であることが好ましく、０．００１ｍｏｌ／Ｌ以上０．１０ｍｏｌ／Ｌ以下であることがさらに好ましく、０．００１ｍｏｌ／Ｌ以上０．０５ｍｏｌ／Ｌ以下であることが最も好ましい。 (Bromite ion)
When the dry etching residue removing solution of the present invention contains bromite ions (BrO 2 - , also written as BrO 2 ), the storage stability of the solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
The concentration of the bromite ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less in terms of the amount of bromite ion. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is low and practicality is low. On the other hand, if it exceeds 0.20 mol/L, the bromite ion is easily decomposed, so that the dry etching residue removal efficiency is difficult to stabilize. In order to stably remove the dry etching residue at a sufficient speed, the concentration of the bromite ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
　亜臭素酸イオンは、残渣除去液中で発生させてもよいし、亜臭素酸塩として残渣除去液に添加してもよい。ここで言う亜臭素酸塩とは、亜臭素酸イオンを含有する塩、または該塩を含む溶液のことである。
　また、酸化剤により臭素含有化合物を酸化することで、残渣除去液中で亜臭素酸イオンを作り出すこともできる。
　亜臭素酸イオンを化合物として残渣除去液に添加するには、亜臭素酸、臭素水、および／または亜臭素酸塩を加えればよい。亜臭素酸塩としては、亜臭素酸ナトリウム、亜臭素酸カリウム、亜臭素酸テトラアルキルアンモニウムが好適であり、半導体製造において問題となる金属イオンを実質的に含まないという点で、亜臭素酸又は亜臭素酸テトラアルキルアンモニウムがさらに好適である。 The bromite ions may be generated in the residue removal solution, or may be added to the residue removal solution as a bromite salt. The bromite salt referred to here means a salt containing bromite ions or a solution containing the salt.
In addition, bromite ions can be produced in the residue removal solution by oxidizing bromine-containing compounds with an oxidizing agent.
To add bromite ions as a compound to the residue removal solution, bromite, bromine water, and/or a bromite may be added. As the bromite, sodium bromite, potassium bromite, and tetraalkylammonium bromite are preferable, and bromite or tetraalkylammonium bromite are more preferable in that they are substantially free of metal ions that are problematic in semiconductor manufacturing.
　残渣除去液中の亜臭素酸イオンの濃度は、広く公知の方法を用いて確認することができる。例えば、紫外可視吸光光度法を用いれば、亜臭素酸イオンに起因する吸収が容易に確認され、その吸収ピーク（残渣除去液のｐＨや亜臭素酸イオン濃度等に依るが、概ね２９８ｎｍ付近）の強度から亜臭素酸イオン濃度を求めることができる。さらに、ヨウ素滴定によっても亜臭素酸イオン濃度を求めることができる。他にも残渣除去液の酸化還元電位（ＯＲＰ）から亜臭素酸イオン濃度を求めることができる。非接触でありかつ連続測定が可能であるという観点から、紫外可視吸光光度法による測定が最も好ましい。なお、紫外可視吸光光度法により亜臭素酸イオン濃度を測定する際、他の化学種による吸収がある場合は、スペクトル分割やベースライン補正などのデータ処理や、リファレンスの適切な選択などを行うことで、亜臭素酸イオン濃度を十分な精度で求めることができる。 The concentration of bromite ions in the residue removal solution can be confirmed by using widely known methods. For example, by using ultraviolet-visible spectrophotometry, the absorption caused by bromite ions can be easily confirmed, and the bromite ion concentration can be calculated from the intensity of the absorption peak (approximately around 298 nm, depending on the pH of the residue removal solution and the bromite ion concentration, etc.). Furthermore, the bromite ion concentration can also be calculated by iodine titration. The bromite ion concentration can also be calculated from the oxidation-reduction potential (ORP) of the residue removal solution. Measurement by ultraviolet-visible spectrophotometry is the most preferable from the viewpoint of non-contact and continuous measurement. Note that when measuring the bromite ion concentration by ultraviolet-visible spectrophotometry, if there is absorption due to other chemical species, the bromite ion concentration can be calculated with sufficient accuracy by performing data processing such as spectrum division and baseline correction, and appropriate selection of a reference.
　（臭素酸イオン）
　本発明のドライエッチング残渣除去液が臭素酸イオン（BｒО３ －、ＢｒО３とも記載）を含む場合、その濃度が０．０００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下であるとき薬液の保存安定性を向上することができる。
　本発明の残渣除去液における前記臭素酸イオンの濃度は、本発明の目的を逸脱しない限り特に制限されることはないが、好ましくは、臭素酸イオン量として０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下である。０．００１ｍｏｌ／Ｌ未満ではドライエッチング残渣除去効率が小さく、実用性が低い。一方、０．２０ｍｏｌ／Ｌを超える場合は、臭素酸イオンの分解が生じやすくなるため、ドライエッチング残渣除去効率が安定しにくくなる。ドライエッチング残渣除去を十分な速度で安定して行うためには、該臭素酸イオンの濃度として０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下であることが好ましく、０．００１ｍｏｌ／Ｌ以上０．１０ｍｏｌ／Ｌ以下であることがさらに好ましく、０．００１ｍｏｌ／Ｌ以上０．０５ｍｏｌ／Ｌ以下であることが最も好ましい。
　臭素酸イオンは、残渣除去液中で発生させてもよいし、臭素酸塩として残渣除去液に添加してもよい。ここで言う臭素酸とは、臭素酸イオンを含有する塩、または該塩を含む溶液のことである。
　また、酸化剤により臭素含有化合物を酸化することで、残渣除去液中で臭素酸イオンを作り出すこともできる。
　臭素酸イオンを化合物として残渣除去液に添加するには、臭素酸、および／または臭素酸塩を加えればよい。臭素酸塩としては、臭素酸ナトリウム、臭素酸カリウム、臭素酸テトラアルキルアンモニウムが好適であり、半導体製造において問題となる金属イオンを含まないという点で、臭素酸又は臭素酸テトラアルキルアンモニウムがさらに好適である。
　残渣除去液中の臭素酸イオンの濃度は、広く公知の方法を用いて確認することができる。例えば、イオンクロマトグラフ分析を用いれば、臭素酸イオンのピークが容易に確認され、その吸収ピークの強度、ピーク面積から液中の臭素酸イオン濃度を求めることができる。他にも残渣除去液の酸化還元電位（ＯＲＰ）、液体クロマトグラフィー質量分析（ＬＣ／ＭＳ）、タンデム型質量分析（ＬＣ／ＭＳ／ＭＳ）から臭素酸イオン濃度を求めることができる。 (Bromate ion)
When the dry etching residue removing solution of the present invention contains bromate ions (BrO 3 - , also written as BrO 3 ), the storage stability of the solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
The concentration of the bromate ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less in terms of the amount of bromate ion. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is small and the practicality is low. On the other hand, if it exceeds 0.20 mol/L, the decomposition of the bromate ion is likely to occur, so that the dry etching residue removal efficiency is difficult to stabilize. In order to stably remove the dry etching residue at a sufficient speed, the concentration of the bromate ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
The bromate ions may be generated in the residue-removing solution, or may be added to the residue-removing solution as a bromate salt. The bromate referred to here means a salt containing bromate ions, or a solution containing the salt.
In addition, bromate ions can be produced in the residue removal solution by oxidizing a bromine-containing compound with an oxidizing agent.
Bromate ions can be added as a compound to the residue removal solution by adding bromic acid and/or a bromate salt. As the bromate salt, sodium bromate, potassium bromate, and tetraalkylammonium bromate are preferable, and bromic acid or tetraalkylammonium bromate is more preferable in that it does not contain metal ions that are problematic in semiconductor manufacturing.
The concentration of bromate ions in the residue-removed liquid can be confirmed by using a widely known method. For example, by using ion chromatography analysis, the peak of bromate ions can be easily confirmed, and the concentration of bromate ions in the liquid can be obtained from the intensity and peak area of the absorption peak. In addition, the concentration of bromate ions can be obtained from the oxidation-reduction potential (ORP) of the residue-removed liquid, liquid chromatography mass spectrometry (LC/MS), and tandem mass spectrometry (LC/MS/MS).
（次亜塩素酸イオン）
　本発明のドライエッチング残渣除去液が次亜塩素酸イオン（ＣｌО－、ＣｌОとも記載）を含む場合、その濃度が０．００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下であるとき薬液の保存安定性を向上することができる。
　次亜塩素酸イオンは、残渣除去液中で発生させてもよいし、次亜塩素酸塩として残渣除去液に添加してもよい。ここで言う次亜塩素酸塩とは、次亜塩素酸イオンを含有する塩、または該塩を含む溶液のことである。次亜塩素酸イオンを残渣除去液中で発生させるには、例えば、塩素ガスを残渣除去液に吹き込めばよい。この場合、次亜塩素酸イオンを効率よく発生させる観点から、残渣除去液は５０℃以下であることが好ましい。残渣除去液が５０℃以下であれば効率よく次亜塩素酸イオンを発生できるだけでなく、発生した次亜塩素酸イオンを安定にドライエッチング残渣除去に用いることができる。さらに、塩素をより多く残渣除去液に溶解させるためには、残渣除去液の温度は３０℃以下であることがより好ましく、２５℃以下であることが最も好ましい。残渣除去液の温度の下限は特に制限されないが、残渣除去液が凍結しないことが好ましい。したがって、残渣除去液は－３５℃以上であることが好ましく、－１５℃以上であることがより好ましく、０℃以上であることが最も好ましい。該塩素ガスを吹き込む残渣除去液のｐＨは特に制限されないが、残渣除去液のｐＨがアルカリ性であれば、次亜塩素酸イオンの生成後、すぐにドライエッチング残渣除去に供することができる。 (Hypochlorite ion)
When the dry etching residue removing solution of the present invention contains hypochlorite ions (also written as ClO − or ClO), the storage stability of the chemical solution can be improved when the concentration is 0.001 mol/L or more and 0.40 mol/L or less.
The hypochlorite ions may be generated in the residue removing liquid, or may be added to the residue removing liquid as hypochlorite. The hypochlorite salt referred to here is a salt containing hypochlorite ions, or a solution containing the salt. To generate hypochlorite ions in the residue removing liquid, for example, chlorine gas may be blown into the residue removing liquid. In this case, from the viewpoint of efficiently generating hypochlorite ions, the residue removing liquid is preferably at 50°C or lower. If the residue removing liquid is at 50°C or lower, not only can hypochlorite ions be efficiently generated, but the generated hypochlorite ions can be stably used for removing dry etching residues. Furthermore, in order to dissolve more chlorine in the residue removing liquid, the temperature of the residue removing liquid is more preferably at 30°C or lower, and most preferably at 25°C or lower. The lower limit of the temperature of the residue removing liquid is not particularly limited, but it is preferable that the residue removing liquid does not freeze. Therefore, the residue removing liquid is preferably at -35°C or higher, more preferably at -15°C or higher, and most preferably at 0°C or higher. The pH of the residue removal solution into which the chlorine gas is blown is not particularly limited, but if the pH of the residue removal solution is alkaline, it can be used to remove dry etching residues immediately after hypochlorite ions are generated.
　さらに、残渣除去液に塩素ガスを吹き込むことで次亜塩素酸イオンを発生させる場合、残渣除去液に塩化物イオン（Ｃｌ－）が含まれていると、塩素ガス（Ｃｌ２）の溶解性が向上する。残渣除去液に溶解したＣｌ２がＣｌ－やＣｌ３ －と反応し、Ｃｌ３ －やＣｌ５ －のような錯イオンを形成し、残渣除去液中で安定化するためである。Ｃｌ２、Ｃｌ－、Ｃｌ３ －、Ｃｌ５ －等を多く含む残渣除去液は、次亜塩素酸イオンをより多く生成できるため、本発明の残渣除去液として好適に用いることができる。
　また、酸化剤により塩素含有化合物を酸化することで、残渣除去液中で次亜塩素酸イオンを作り出すこともできる。 Furthermore, when hypochlorite ions are generated by blowing chlorine gas into the residue removal liquid, the solubility of chlorine gas (Cl 2 ) is improved if the residue removal liquid contains chloride ions (Cl - ). This is because Cl 2 dissolved in the residue removal liquid reacts with Cl - or Cl 3 - to form complex ions such as Cl 3 - or Cl 5 - , which are stabilized in the residue removal liquid. A residue removal liquid containing a large amount of Cl 2 , Cl - , Cl 3 - , Cl 5 - or the like can generate more hypochlorite ions, and therefore can be suitably used as the residue removal liquid of the present invention.
In addition, hypochlorite ions can be produced in the residue removal solution by oxidizing chlorine-containing compounds with an oxidizing agent.
　次亜塩素酸イオンを化合物として残渣除去液に添加するには、次亜塩素酸、塩素水、および／または次亜塩素酸塩を加えればよい。次亜塩素酸塩としては、次亜塩素酸ナトリウム、次亜塩素酸カリウム、次亜塩素酸テトラアルキルアンモニウムが好適であり、半導体製造において問題となる金属イオンを実質的に含まないという点で、次亜塩素酸又は次亜塩素酸テトラアルキルアンモニウムがさらに好適である。
　該次亜塩素酸テトラアルキルアンモニウムは、水酸化テトラアルキルアンモニウム溶液に塩素ガスを通じることで容易に得られる。また、次亜塩素酸と水酸化テトラアルキルアンモニウム溶液を混合することでも得られる。さらに、次亜塩素酸ナトリウムなどの次亜塩素酸塩に含まれるカチオンを、イオン交換樹脂を用いてテトラアルキルアンモニウムイオンに置換することでも次亜塩素酸テトラアルキルアンモニウムを得ることができる。 To add hypochlorite ions as a compound to the residue removing solution, hypochlorous acid, chlorine water, and/or hypochlorite may be added. As the hypochlorite, sodium hypochlorite, potassium hypochlorite, and tetraalkylammonium hypochlorite are preferable, and hypochlorous acid or tetraalkylammonium hypochlorite is more preferable because it is substantially free of metal ions that are problematic in semiconductor manufacturing.
The tetraalkylammonium hypochlorite can be easily obtained by passing chlorine gas through a tetraalkylammonium hydroxide solution. It can also be obtained by mixing hypochlorous acid with a tetraalkylammonium hydroxide solution. Furthermore, tetraalkylammonium hypochlorite can also be obtained by replacing the cation contained in hypochlorite such as sodium hypochlorite with tetraalkylammonium ion using ion exchange resin.
　本発明の残渣除去液における該次亜塩素酸イオンの濃度は、本発明の目的を逸脱しない限り特に制限されることはないが、好ましくは、次亜塩素酸イオンとして０．００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下である。０．００１ｍｏｌ／Ｌ未満ではドライエッチング残渣除去効率が小さく、実用性が低い。一方、０．４０ｍｏｌ／Ｌを超える場合は、次亜塩素酸イオンの分解が生じやすくなるため、ドライエッチング残渣除去効率が安定しにくくなるドライエッチング残渣除去を十分な速度で安定して行うためには、該次亜塩素酸イオンの濃度０．００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下であるであることが好ましく、０．０１ｍｏｌ／Ｌ以上０．３０ｍｏｌ／Ｌ以下であることがさらに好ましく、０．１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下であることが最も好ましい。 The concentration of the hypochlorite ions in the residue removal solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.40 mol/L or less in terms of hypochlorite ions. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is low and practicality is low. On the other hand, if it exceeds 0.40 mol/L, decomposition of the hypochlorite ions is likely to occur, and the dry etching residue removal efficiency becomes less stable. In order to stably remove dry etching residues at a sufficient speed, the concentration of the hypochlorite ions is preferably 0.001 mol/L or more and 0.40 mol/L or less, more preferably 0.01 mol/L or more and 0.30 mol/L or less, and most preferably 0.1 mol/L or more and 0.20 mol/L or less.
　残渣除去液中の次亜塩素酸イオンの濃度は、広く公知の方法を用いて確認することができる。例えば、紫外可視吸光光度法を用いれば、次亜塩素酸イオンに起因する吸収が容易に確認され、その吸収ピーク（残渣除去液のｐＨや次亜塩素酸イオン濃度等に依るが、概ね２９２ｎｍ付近）の強度から次亜塩素酸イオン濃度を求めることができる。さらに、ヨウ素滴定によっても次亜塩素酸イオン濃度を求めることができる。他にも残渣除去液の酸化還元電位（ＯＲＰ）から次亜塩素酸イオン濃度を求めることができる。非接触でありかつ連続測定が可能であるという観点から、紫外可視吸光光度法による測定が最も好ましい。なお、紫外可視吸光光度法により次亜塩素酸イオン濃度を測定する際、他の化学種による吸収がある場合は、スペクトル分割やベースライン補正などのデータ処理や、リファレンスの適切な選択などを行うことで、次亜塩素酸イオン濃度を十分な精度で求めることができる。 The concentration of hypochlorite ions in the residue removal solution can be confirmed using widely known methods. For example, by using ultraviolet-visible spectrophotometry, the absorption caused by hypochlorite ions can be easily confirmed, and the hypochlorite ion concentration can be calculated from the intensity of the absorption peak (approximately around 292 nm, depending on the pH of the residue removal solution and the hypochlorite ion concentration, etc.). Furthermore, the hypochlorite ion concentration can also be calculated by iodometric titration. The hypochlorite ion concentration can also be calculated from the oxidation-reduction potential (ORP) of the residue removal solution. Measurement by ultraviolet-visible spectrophotometry is the most preferable from the viewpoint of non-contact and continuous measurement. Note that when measuring the hypochlorite ion concentration by ultraviolet-visible spectrophotometry, if there is absorption due to other chemical species, the hypochlorite ion concentration can be calculated with sufficient accuracy by performing data processing such as spectrum division and baseline correction, and appropriate selection of a reference.
　（亜塩素酸イオン）
　本発明のドライエッチング残渣除去液が亜塩素酸イオン（ＣｌО２ －、ＣｌО２とも記載）を含む場合、その濃度が０．０００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下であるとき薬液の保存安定性を向上することができる。
　本発明の残渣除去液における前記亜塩素酸イオンの濃度は、本発明の目的を逸脱しない限り特に制限されることはないが、好ましくは、亜塩素酸イオン量として０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下である。０．００１ｍｏｌ／Ｌ未満ではドライエッチング残渣除去効率が小さく、実用性が低い。一方、０．２０ｍｏｌ／Ｌを超える場合は、亜塩素酸イオンの分解が生じやすくなるため、ドライエッチング残渣除去効率が安定しにくくなる。ドライエッチング残渣除去を十分な速度で安定して行うためには、該亜塩素酸イオンの濃度として０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下であることが好ましく、０．００１ｍｏｌ／Ｌ以上０．１０ｍｏｌ／Ｌ以下であることがさらに好ましく、０．００１ｍｏｌ／Ｌ以上０．０５ｍｏｌ／Ｌ以下であることが最も好ましい。
　亜塩素酸イオンは、残渣除去液中で発生させてもよいし、亜塩素酸塩として残渣除去液に添加してもよい。ここで言う亜塩素酸塩とは、亜塩素酸イオンを含有する塩、または該塩を含む溶液のことである。
　また、酸化剤により塩素含有化合物を酸化することで、残渣除去液中で亜塩素酸イオンを作り出すこともできる。
　亜塩素酸イオンを化合物として残渣除去液に添加するには、亜塩素酸、塩素水、および／または亜塩素酸塩を加えればよい。亜塩素酸塩としては、亜塩素酸ナトリウム、亜塩素酸カリウム、亜塩素酸テトラアルキルアンモニウムが好適であり、半導体製造において問題となる金属イオンを実質的に含まないという点で、亜塩素酸又は亜塩素酸テトラアルキルアンモニウムがさらに好適である。
　残渣除去液中の亜塩素酸イオンの濃度は、広く公知の方法を用いて確認することができる。例えば、イオンクロマトグラフ分析を用いれば、亜塩素酸イオンのピークが容易に確認され、その吸収ピークの強度、ピーク面積から液中の亜塩素酸イオン濃度を求めることができる。 (Chlorite ion)
When the dry etching residue removing solution of the present invention contains chlorite ions (also written as ClO 2 − or ClO 2 ), the storage stability of the chemical solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
The concentration of the chlorite ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 0.001 mol/L or more and 0.20 mol/L or less as the amount of chlorite ion. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is small and practical. On the other hand, if it exceeds 0.20 mol/L, the decomposition of the chlorite ion is likely to occur, so that the dry etching residue removal efficiency is difficult to stabilize. In order to stably remove the dry etching residue at a sufficient speed, the concentration of the chlorite ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
The chlorite ion may be generated in the residue removing solution, or may be added to the residue removing solution as a chlorite. The chlorite salt referred to here means a salt containing chlorite ion or a solution containing the salt.
In addition, chlorite ions can be produced in the residue removal solution by oxidizing chlorine-containing compounds with an oxidizing agent.
To add chlorite ions as a compound to the residue removing solution, chlorous acid, chlorine water, and/or a chlorite may be added. As the chlorite, sodium chlorite, potassium chlorite, and tetraalkylammonium chlorite are preferable, and chlorous acid or tetraalkylammonium chlorite is more preferable in that it is substantially free of metal ions that are problematic in semiconductor manufacturing.
The concentration of chlorite ions in the residue removal solution can be confirmed by using a widely known method. For example, by using ion chromatography analysis, the peak of chlorite ions can be easily confirmed, and the concentration of chlorite ions in the solution can be obtained from the intensity and area of the absorption peak.
　（塩素酸イオン）
　本発明のドライエッチング残渣除去液が塩素酸イオン（ＣｌО３ －、ＣｌО３とも記載）を含む場合、その濃度が０．０００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下であるとき薬液の保存安定性を向上することができる。
　本発明の残渣除去液における前記塩素酸イオンの濃度は、本発明の目的を逸脱しない限り特に制限されることはないが、好ましくは、塩素酸イオン量として０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下である。０．００１ｍｏｌ／Ｌ未満ではドライエッチング残渣除去効率が小さく、実用性が低い。一方、０．２０ｍｏｌ／Ｌを超える場合は、塩素酸イオンの分解が生じやすくなるため、ドライエッチング残渣除去効率が安定しにくくなる。ドライエッチング残渣除去を十分な速度で安定して行うためには、該塩素酸イオンの濃度として０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下であることが好ましく、０．００１ｍｏｌ／Ｌ以上０．１０ｍｏｌ／Ｌ以下であることがさらに好ましく、０．００１ｍｏｌ／Ｌ以上０．０５ｍｏｌ／Ｌ以下であることが最も好ましい。
　塩素酸イオンは、残渣除去液中で発生させてもよいし、塩素酸塩として残渣除去液に添加してもよい。ここで言う塩素酸とは、塩素酸イオンを含有する塩、または該塩を含む溶液のことである。
　また、酸化剤により塩素含有化合物を酸化することで、残渣除去液中で塩素酸イオンを作り出すこともできる。
　塩素酸イオンを化合物として残渣除去液に添加するには、塩素酸、および／または塩素酸塩を加えればよい。塩素酸塩としては、塩素酸ナトリウム、塩素酸カリウム、塩素酸テトラアルキルアンモニウムが好適であり、半導体製造において問題となる金属イオンを含まないという点で、塩素酸又は塩素酸テトラアルキルアンモニウムがさらに好適である。
　残渣除去液中の塩素酸イオンの濃度は、広く公知の方法を用いて確認することができる。例えば、イオンクロマトグラフ分析を用いれば、塩素酸イオンのピークが容易に確認され、その吸収ピークの強度、ピーク面積から液中の塩素酸イオン濃度を求めることができる。他にも残渣除去液の酸化還元電位（ＯＲＰ）から塩素酸イオン濃度を求めることができる。 (chlorate ion)
When the dry etching residue removing solution of the present invention contains chlorate ions (ClO 3 − , also written as ClO 3 ), the storage stability of the solution can be improved when the concentration is 0.0001 mol/L or more and 0.40 mol/L or less.
The concentration of the chlorate ion in the residue removing solution of the present invention is not particularly limited as long as it does not deviate from the object of the present invention, but preferably, the amount of chlorate ion is 0.001 mol/L or more and 0.20 mol/L or less. If it is less than 0.001 mol/L, the dry etching residue removal efficiency is small and practical. On the other hand, if it exceeds 0.20 mol/L, the decomposition of chlorate ion is easily caused, so that the dry etching residue removal efficiency is difficult to stabilize. In order to stably remove dry etching residue at a sufficient speed, the concentration of the chlorate ion is preferably 0.001 mol/L or more and 0.20 mol/L or less, more preferably 0.001 mol/L or more and 0.10 mol/L or less, and most preferably 0.001 mol/L or more and 0.05 mol/L or less.
The chlorate ions may be generated in the residue-removing solution, or may be added to the residue-removing solution as a chlorate salt. The chlorate referred to here means a salt containing chlorate ions, or a solution containing the salt.
In addition, chlorine-containing compounds can be oxidized with an oxidizing agent to produce chlorate ions in the residue removal solution.
In order to add chlorate ions as a compound to the residue removal solution, chloric acid and/or a chlorate may be added. As the chlorate, sodium chlorate, potassium chlorate, and tetraalkylammonium chlorate are preferable, and chloric acid or tetraalkylammonium chlorate is more preferable because it does not contain metal ions that are problematic in semiconductor manufacturing.
The concentration of chlorate ion in the residue-removing solution can be confirmed by using a widely known method.For example, by using ion chromatography analysis, the peak of chlorate ion can be easily confirmed, and the concentration of chlorate ion in the solution can be obtained from the intensity and peak area of the absorption peak.Otherwise, the concentration of chlorate ion can be obtained from the oxidation-reduction potential (ORP) of the residue-removing solution.
（ドライエッチング残渣除去液のｐＨ）
　次亜臭素酸（ＨＢｒＯ）と次亜臭素酸イオン（ＢｒＯ－）の酸解離定数（ｐＫａ）は８．６であり、次亜塩素酸（ＨＣｌＯ）と次亜塩素酸イオン（ＣｌＯ－）の酸解離定数（ｐＫａ）は７．５であるため、ｐＨが低い場合等、残渣除去液のｐＨによってＨＢｒＯとＢｒＯ－、あるいはＨＣｌＯとＣｌＯ－が共存する場合がある。残渣除去液にＨＢｒＯとＢｒＯ－が含まれる場合は、ＨＢｒＯとＢｒＯ－の合計濃度を上記次亜臭素酸イオンの濃度として、扱えばよい。同様に残渣除去液にＨＣｌＯとＣｌＯ－が含まれる場合は、ＨＣｌＯとＣｌＯ－の合計濃度を上記次亜塩素酸イオンの濃度として、扱えばよい。 (pH of dry etching residue removal solution)
The acid dissociation constant (pK a ) of hypobromous acid (HBrO) and hypobromite ion (BrO − ) is 8.6, and the acid dissociation constant (pK a ) of hypochlorous acid (HClO) and hypochlorite ion (ClO − ) is 7.5, so that when the pH is low, HBrO and BrO − , or HClO and ClO − may coexist depending on the pH of the residue removal solution. When the residue removal solution contains HBrO and BrO − , the total concentration of HBrO and BrO − may be treated as the concentration of the hypobromite ion. Similarly, when the residue removal solution contains HClO and ClO − , the total concentration of HClO and ClO − may be treated as the concentration of the hypochlorite ion.
　残渣除去液のｐＨを調整するために、酸またはアルカリを残渣除去液に添加することができる。該酸としては、無機酸、有機酸のいずれであってもよく、一例を挙げれば、フッ酸、塩酸、臭化水素酸、硝酸、酢酸、硫酸、ペルオキソ二硫酸、ギ酸、酢酸などのカルボン酸等であるが、この他にも半導体用の残渣除去液に用いられる広く公知の酸を何ら制限なく用いることができる。該アルカリとしては、半導体製造において問題となる金属イオンを含まないことから、有機アルカリを用いることが好ましい。有機アルカリの一例を挙げれば、テトラアルキルアンモニウムイオンと水酸化物イオンからなる、水酸化テトラアルキルアンモニウムである。該水酸化テトラアルキルアンモニウムの例を挙げれば、水酸化テトラメチルアンモニウム、水酸化テトラエチルアンモニウム、水酸化テトラプロピルアンモニウム、水酸化テトラブチルアンモニウム、水酸化エチルトリメチルアンモニウム、水酸化プロピルトリメチルアンモニウム等が挙げられる。なかでも、単位重量当たりの水酸化物イオン数が多く、高純度品が容易に入手可能であることから、該有機アルカリは水酸化テトラアルキルアンモニウムであることが好ましく、水酸化テトラメチルアンモニウムであることがより好ましい。
　残渣除去液中に含まれる上記テトラアルキルアンモニウムイオンは、１種類であってもよいし、複数組み合わせて使用してもよい。 In order to adjust the pH of the residue removal solution, an acid or an alkali can be added to the residue removal solution. The acid may be either an inorganic acid or an organic acid, and examples include hydrofluoric acid, hydrochloric acid, hydrobromic acid, nitric acid, acetic acid, sulfuric acid, peroxodisulfuric acid, formic acid, carboxylic acids such as acetic acid, and other widely known acids used in residue removal solutions for semiconductors can be used without any restrictions. As the alkali, it is preferable to use an organic alkali because it does not contain metal ions that are problematic in semiconductor manufacturing. An example of an organic alkali is tetraalkylammonium hydroxide, which is composed of tetraalkylammonium ions and hydroxide ions. Examples of the tetraalkylammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ethyltrimethylammonium hydroxide, propyltrimethylammonium hydroxide, and the like. Among them, the organic alkali is preferably tetraalkylammonium hydroxide, and more preferably tetramethylammonium hydroxide, because it has a large number of hydroxide ions per unit weight and is easily available as a high-purity product.
The residue removing solution may contain one type of tetraalkylammonium ion, or a combination of two or more types of tetraalkylammonium ions.
（ドライエッチング残渣除去液に含まれる金属）
　ドライエッチング残渣除去液が０．０１ｐｐｔ以上１０００ｐｐｔ以下のＭｇ、Ｃａ、Ｎａ、及びＫから成る群から選択される１種以上の金属を特定金属として含有することにより、更に、被処理物に対して表面の平滑性を保持する効果がある。 (Metals contained in dry etching residue removal solution)
The dry etching residue removal solution contains one or more metals selected from the group consisting of Mg, Ca, Na, and K in an amount of 0.01 ppt or more and 1000 ppt or less as specific metals, which further has the effect of maintaining the surface smoothness of the workpiece.
　メカニズムは明確ではないが、遷移金属含有物表面上に対象混合物が吸着し電子状態が均一化されると考えられることから、残渣除去液中にＭｇ、Ｃａ、Ｎａ、及びＫから成る群から選択される１種以上の金属が含まれることで、被処理物の表面の平滑性を保持する効果がある。また、残渣除去液中に含まれる、Ｍｇ、Ｃａ、Ｎａ、及びＫから成る群から選択される１種以上の金属の合計含有量は、０．０１ｐｐｔ以上１０００ｐｐｔ以下であり、より好ましくは０．０１ｐｐｔ以上２００ｐｐｔ以下であり、さらに好ましくは０．０１ｐｐｔ以上５０ｐｐｔ以下である。
　なお、ドライエッチング残渣除去液には、Ｍｇのみ、Ｃａのみ、Ｎａのみ、Ｋのみ、ＭｇとＣａとＮａとＫ、ＭｇとＣａとＮａのみ、ＭｇとＣａとＫのみ、ＭｇとＮａとＫのみ、ＣａとＮａとＫのみ、ＭｇとＣａのみ、ＭｇとＮａのみ、ＭｇとＫのみ、ＣａとＮａのみ、ＣａとＫのみ、またはＮａとＫのみが含まれる場合がある。エッチング残渣除去液に含まれる特定金属の含有量は、含まれる金属の全ての含有量の合計である。
　また、ドライエッチング残渣除去液には、製造工程によって、Ｍｇ、Ｃａ、Ｎａ、及びＫ以外のアルカリ金属、アルカリ土類金属、Ｆｅ、Ｃｒ、Ｎｉ、Ｚｎ、Ｃｕ及びＡｌから成る群から選択される１種以上の金属が含まれる場合がある。これらは表面の平滑性に寄与しないが、含有されてもよい。
　本発明のドライエッチング残渣除去液中にはその製造工程や原料に由来する塩化物イオン、臭化物イオン、ヨウ化物イオンが含まれることがある。それらの含有量はドライエッチング残渣除去に影響を与えない濃度であれば問題なく使用でき、それらの個々の濃度として１質量％を超えないことが好ましい。 Although the mechanism is not clear, it is believed that the target mixture is adsorbed onto the surface of the transition metal-containing material to homogenize the electronic state, and therefore, there is an effect of maintaining the smoothness of the surface of the treated object by containing one or more metals selected from the group consisting of Mg, Ca, Na, and K in the residue removal solution. In addition, the total content of one or more metals selected from the group consisting of Mg, Ca, Na, and K contained in the residue removal solution is 0.01 ppt or more and 1000 ppt or less, more preferably 0.01 ppt or more and 200 ppt or less, and even more preferably 0.01 ppt or more and 50 ppt or less.
The dry etching residue removal solution may contain only Mg, only Ca, only Na, only K, Mg, Ca, Na, and K, Mg, Ca, and Na, only Mg, Ca, and K, only Mg, Na, and K, only Ca, Na, and K, only Mg and Ca, only Mg and Na, only Mg and K, only Ca and Na, only Ca and K, or only Na and K. The content of a specific metal contained in the etching residue removal solution is the total content of all metals contained therein.
Depending on the manufacturing process, the dry etching residue removal solution may contain one or more metals selected from the group consisting of alkali metals other than Mg, Ca, Na, and K, alkaline earth metals, Fe, Cr, Ni, Zn, Cu, and Al. These do not contribute to the smoothness of the surface, but may be contained.
The dry etching residue removing solution of the present invention may contain chloride ions, bromide ions, and iodide ions derived from the manufacturing process or raw materials. The contents of these ions may be used without problems as long as they are at concentrations that do not affect the removal of dry etching residues, and each concentration of these ions preferably does not exceed 1 mass %.
（オニウムイオン）
　残渣除去液がオニウムイオンを含有することにより、表面の平滑性の保持に効果がある。残渣除去工程により、被処理物の表面もエッチングされるため、表面の平滑性が処理前後で変化しないことが求められる。被処理物の表面の平滑性を好ましい範囲に保つためには、下記、式（１）～（６）で示す構造のオニウムイオンからなる群から選択される一種以上を選択する事が好ましい。
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000014
Figure JPOXMLDOC01-appb-C000015
Figure JPOXMLDOC01-appb-C000016
 
Figure JPOXMLDOC01-appb-C000017
 
Figure JPOXMLDOC01-appb-C000018
 (Onium ion)
The residue removal solution contains onium ions, which are effective in maintaining the smoothness of the surface. Since the surface of the workpiece is also etched by the residue removal step, it is required that the smoothness of the surface does not change before and after the treatment. In order to maintain the smoothness of the surface of the workpiece within a preferred range, it is preferable to select one or more types selected from the group consisting of onium ions having structures represented by the following formulas (1) to (6).
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000014
Figure JPOXMLDOC01-appb-C000015
Figure JPOXMLDOC01-appb-C000016

Figure JPOXMLDOC01-appb-C000017

Figure JPOXMLDOC01-appb-C000018
（式（１）～式（６）中、
　Ｒ１、Ｒ２、Ｒ３、Ｒ４、Ｒ５、Ｒ６は独立して、炭素数２～９のアルキル基、アリル基、炭素数１～９のアルキル基を有するアラルキル基、又はアリール基である。また、アラルキル基中のアリール基及びアリール基の環において少なくとも１つの水素は、フッ素、塩素、炭素数１～９のアルキル基、炭素数２～９のアルケニル基、炭素数１～９のアルコキシ基、又は炭素数２～９のアルケニルオキシ基で置き換えられてもよく、これらの基において、少なくとも１つの水素は、フッ素、塩素、臭素、又はヨウ素で置き換えられてもよい。 (In formula (1) to formula (6),
R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently an alkyl group having 2 to 9 carbon atoms, an allyl group, an aralkyl group having an alkyl group having 1 to 9 carbon atoms, or an aryl group. In addition, at least one hydrogen atom in the aryl group in the aralkyl group and in the ring of the aryl group may be replaced by fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkenyloxy group having 2 to 9 carbon atoms, and in these groups, at least one hydrogen atom may be replaced by fluorine, chlorine, bromine or iodine.
　上記のオニウムイオンに対するカウンターアニオンとしては、フッ化物イオン、塩化物イオン、臭化物イオン、ヨウ化物イオン、水酸化物イオン、硝酸イオン、リン酸イオン、硫酸イオン、硫酸水素イオン、メタン硫酸イオン、過塩素酸イオン、塩素酸イオン、亜塩素酸イオン、次亜塩素酸イオン、過臭素酸イオン、臭素酸イオン、亜臭素酸イオン、次亜臭素酸イオン、オルト過ヨウ素酸イオン、メタ過ヨウ素酸イオン、ヨウ素酸イオン、亜ヨウ素酸イオン、次亜ヨウ素酸イオン、酢酸イオン、炭酸イオン、炭酸水素イオン、フルオロホウ酸イオン、又はトリフルオロ酢酸イオンを挙げることができる。
　Ａはアンモニウムイオン、又はホスホニウムイオンである。
　Ｚは、窒素、硫黄、酸素原子を含んでもよい芳香族基又は脂環式基であり、該芳香族基又は該脂環式基において、炭素又は窒素は、塩素、臭素、フッ素、ヨウ素、少なくとも１つの炭素数１～９のアルキル基、少なくとも１つの炭素数２～９のアルケニルオキシ基、少なくとも１つの炭素数１～９のアルキル基で置換されてもよい芳香族基、又は、少なくとも１つの炭素数１～９のアルキル基で置換されてもよい脂環式基を有していてもよい。
　Ｒは塩素、臭素、フッ素、ヨウ素、炭素数１～９のアルキル基、アリル基、少なくとも１つの炭素数１～９のアルキル基で置換されてもよい芳香族基、又は少なくとも１つの炭素数１～９のアルキル基で置換されてもよい脂環式基である。ｎは１又は２の整数であり、Ｒの数を示す。ｎが２の場合、Ｒは同一又は異なっていてもよく、環を形成してもよい。
　ａは１～１０の整数である。 Examples of counter anions to the onium ions include fluoride ion, chloride ion, bromide ion, iodide ion, hydroxide ion, nitrate ion, phosphate ion, sulfate ion, hydrogen sulfate ion, methanesulfate ion, perchlorate ion, chlorate ion, chlorite ion, hypochlorite ion, perbromate ion, bromate ion, bromite ion, hypobromite ion, orthoperiodate ion, metaperiodate ion, iodate ion, iodite ion, hypoiodite ion, acetate ion, carbonate ion, hydrogen carbonate ion, fluoroborate ion, and trifluoroacetate ion.
A is an ammonium ion or a phosphonium ion.
Z is an aromatic group or an alicyclic group which may contain nitrogen, sulfur or oxygen atoms, and in the aromatic group or the alicyclic group, carbon or nitrogen may have chlorine, bromine, fluorine, iodine, at least one alkyl group having 1 to 9 carbon atoms, at least one alkenyloxy group having 2 to 9 carbon atoms, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
R is chlorine, bromine, fluorine, iodine, an alkyl group having 1 to 9 carbon atoms, an allyl group, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms. n is an integer of 1 or 2 and indicates the number of R. When n is 2, R may be the same or different and may form a ring.
a is an integer from 1 to 10.
　式中Ｒで示される炭化水素基は、長鎖であるほど疎水性が高くなる。そのため、長鎖の炭化水素基を有するオニウムイオンを含む残渣除去液ほど、表面張力は低下する傾向にある。一方で、炭化水素鎖が短すぎると、オニウムイオンの効果である、表面平滑性の向上やＲｕＯ４ガスの抑制効果が制限されてしまう。このような理由から、炭化水素基の炭素数は、上述の範囲内である事が好ましい。 The longer the chain of the hydrocarbon group represented by R in the formula, the higher the hydrophobicity. Therefore, the longer the chain of the onium ion with a hydrocarbon group, the lower the surface tension of the residue removal liquid tends to be. On the other hand, if the hydrocarbon chain is too short, the effect of the onium ion, such as improving surface smoothness and suppressing RuO4 gas, is limited. For these reasons, the number of carbon atoms in the hydrocarbon group is preferably within the above-mentioned range.
　残渣除去液がオニウムイオンを含有することにより、金属酸化物によるガスの発生を抑制することができる。例示するなら、被処理物がルテニウムである場合、残渣除去液中の酸化剤によりルテニウムが酸化され、ＲｕＯ４ －、ＲｕＯ４ ２－等が発生する。発生したＲｕＯ４ －、ＲｕＯ４ ２－等がオニウムイオンと相互作用することによりＲｕＯ４ガスの発生が抑制される。 The residue removal solution contains onium ions, which can suppress the generation of gas due to metal oxides. For example, when the object to be treated is ruthenium, the ruthenium is oxidized by the oxidizing agent in the residue removal solution to generate RuO 4 - , RuO 4 2- , etc. The generated RuO 4 - , RuO 4 2- , etc. interact with the onium ions to suppress the generation of RuO 4 gas.
（オニウムイオンの濃度）
　本発明の残渣除去液中のオニウムイオンの濃度は１質量ｐｐｍ以上１０，０００質量ｐｐｍ以下であることが好ましい。オニウムイオンの添加量が少なすぎると、ＲｕＯ４ －等の被処理物との相互作用が弱まり例えばＲｕＯ４ガス抑制効果が低減するだけでなく、残渣除去時に金属表面へ付着するオニウムイオンの量が不十分となるため、表面平滑性が低下する傾向にある。一方、添加量が多すぎると、オニウムイオンの金属表面への吸着量が過多となって、残渣除去率が低下する。また、残渣除去液中の酸化剤とオニウムイオンが反応する事で酸化剤の濃度低下の原因となる場合がある。したがって、本発明の残渣除去液は、オニウムイオンを１質量ｐｐｍ以上１０，０００質量ｐｐｍ以下含むことが好ましく、１０質量ｐｐｍ以上５，０００質量ｐｐｍ以下含むことがより好ましく、５０質量ｐｐｍ以上２０００質量ｐｐｍ以下含むことがさらに好ましい。なお、オニウムイオンを添加する場合には、１種のみを添加してもよいし、２種以上を組み合わせて添加してもよい。２種類以上のオニウムイオンを含む場合であっても、オニウムイオンの濃度の合計が上記の濃度範囲であれば、ＲｕＯ４ガスの発生を効果的に抑制することができる。 (Onium ion concentration)
The concentration of the onium ion in the residue removing solution of the present invention is preferably 1 mass ppm or more and 10,000 mass ppm or less. If the amount of onium ion added is too small, not only the interaction with the workpiece such as RuO 4 - is weakened, for example, the RuO 4 gas suppression effect is reduced, but also the amount of onium ion attached to the metal surface during residue removal is insufficient, so that the surface smoothness tends to decrease. On the other hand, if the amount added is too large, the amount of onium ion adsorbed to the metal surface becomes excessive, and the residue removal rate decreases. In addition, the reaction between the oxidizing agent in the residue removing solution and the onium ion may cause a decrease in the concentration of the oxidizing agent. Therefore, the residue removing solution of the present invention preferably contains onium ion in an amount of 1 mass ppm or more and 10,000 mass ppm or less, more preferably 10 mass ppm or more and 5,000 mass ppm or less, and even more preferably 50 mass ppm or more and 2000 mass ppm or less. When onium ions are added, only one type may be added, or two or more types may be added in combination. Even when two or more types of onium ions are contained, so long as the total concentration of the onium ions is within the above concentration range, the generation of RuO4 gas can be effectively suppressed.
　このようなオニウムイオンを例示すれば、クロロコリンイオン、ブロモコリン、ｔｒａｎｓ－２－ブテン１，４－ビス（トリフェニルホスホニウムイオン）、１－ヘキシル－３－メチルイミダゾリウムイオン、アリルトリフェニルホスホニウムイオン、テトラフェニルホスホニウムイオン、ベンジルトリフェニルホスホニウムイオン、メチルトリフェニルホスホニウムイオン、（２－カルボキシエチル）トリフェニルホスホニウムイオン、（３－カルボキシプロピル）トリフェニルホスホニウムイオン、（４－カルボキシブチル）トリフェニルホスホニウムイオン、（５－カルボキシペンチル）トリフェニルホスホニウムイオン、シンナミルトリフェニルホスホニウムイオン、（２－ヒドロキシベンジル）トリフェニルホスホニウムイオン、（１－ナフチルメチル）トリフェニルホスホニウムイオン、ブチルトリフェニルホスホニウムイオン、（ｔｅｒｔ－ブトキシカルボニルメチル）トリフェニルホスホニウムイオン、アリルトリフェニルホスホニウムイオン、（３－メトキシベンジル）トリフェニルホスホニウムイオン、（メトキシメチル）トリフェニルホスホニウムイオン、（１－エトキシー１－オキソプロパンー２－イル）トリフェニルホスホニウムイオン、（３，４－ジメトキシベンジル）トリフェニルホスホニウムイオン、メトキシカルボニルメチル（トリフェニル）ホスホニウムイオン、（２，４－ジクロロベンジル）トリフェニルホスホニウムイオン、（２－ヒドロキシー５－メチルフェニル）トリフェニルホスホニウムイオン、（４－クロロベンンジル）トリフェニルホスホニウムイオン、（３－クロロ－２－ヒドロキシプロピル）トリメチルアンモニウムイオン、メタクロイルコリンイオン、ベンゾイルコリンイオン、ベンジルジメチルフェニルアンモニウムイオン、（２－メトキシエトキシメチル）トリエチルアンモニウムイオン、カルバミルコリンイオン、１，１’－ジフルオロ－２，２'－ビピリジニウムビス（テトラフルオロボラート）、ベンジルトリブチルアンモニウムイオン、トリメチルフェニルアンモニウムイオン、５－アゾニアスピロ［４．４］ノナンイオン、トリブチルメチルアンモニウムイオン、テトラブチルアンモニウムイオン、テトラペンチルアンモニウムイオン、テトラブチルホスホニウムイオン、ジアリルジメチルアンモニウムイオン、１，１－ジメチルピペリジニウムイオン、（２－ヒドロキシエチル）ジメチル（３－スルホプロピル）アンモニウムヒドロキシド、３－（トリフルオロメチル）フェニルトリメチルアンモニウムイオン、１，１'－（デカン－１，１０－ジイル）ビス［４－アザ－１－アゾニアビシクロ［２．２．２］オクタン］ジイオン、(３－ブロモプロピル）トリメチルアンモニウムイオン、ビニルベンジルトリメチルアンモニウムイオン、アリルトリメチルアンモニウムイオン、トリメチルビニルアンモニウムイオン、コリンイオン、β-メチルコリンイオン、トリフェニルスルホニウムイオン、エチルトリメチルアンモニウム、およびプロピルトリメチルアンモニウム等が挙げられ、好ましくは、ベンジルジメチルフェニルアンモニウムイオン、（１－エトキシー１－オキソプロパンー２－イル）トリフェニルホスホニウムイオン、１，１'－（デカン－１，１０－ジイル）ビス[４－アザ－１－アゾニアビシクロ［２．２．２］オクタン］ジイオン、ブチルトリフェニルホスホニウムイオン、（２－カルボキシエチル）トリフェニルホスホニウムイオン、（３－カルボキシプロピル）トリフェニルホスホニウムイオン、（４－カルボキシブチル）トリフェニルホスホニウムイオン、アリルトリフェニルホスホニウムイオン、テトラフェニルホスホニウムイオン、およびベンジルトリフェニルホスホニウムイオンからなる群から選択される１種以上である。 Examples of such onium ions include chlorocholine ion, bromocholine, trans-2-butene 1,4-bis(triphenylphosphonium ion), 1-hexyl-3-methylimidazolium ion, allyltriphenylphosphonium ion, tetraphenylphosphonium ion, benzyltriphenylphosphonium ion, methyltriphenylphosphonium ion, (2-carboxyethyl)triphenylphosphonium ion, (3-carboxypropyl)triphenylphosphonium ion, (4-carboxybutyl)triphenylphosphonium ion, (5-carboxypentyl)triphenylphosphonium ion, cinnamyltriphenylphosphonium ion, (2-hydroxybenzyl)triphenylphosphonium ion, (1-naphthylmethyl)triphenylphosphonium ion, butyltriphenylphosphonium ion, (tert-butoxycarbonylmethyl)triphenylphosphonium ion, (1-methoxybenzyl)triphenylphosphonium ion, allyltriphenylphosphonium ion, (3-methoxybenzyl)triphenylphosphonium ion, (methoxymethyl)triphenylphosphonium ion, (1-ethoxy-1-oxopropan-2-yl)triphenylphosphonium ion, (3,4-dimethoxybenzyl)triphenylphosphonium ion, methoxycarbonylmethyl(triphenyl)phosphonium ion, (2,4-dichlorobenzyl)triphenylphosphonium ion, (2-hydroxy-5-methylphenyl)triphenylphosphonium ion, (4-chlorobenzyl)triphenylphosphonium ion, (3-chloro-2-hydroxypropyl)trimethylammonium ion, methacroylcholine ion, benzoylcholine ion, benzyldimethylphenylammonium ion, (2-methoxyethoxymethyl)triethylammonium ion, carbamyl Choline ion, 1,1'-difluoro-2,2'-bipyridinium bis(tetrafluoroborate), benzyltributylammonium ion, trimethylphenylammonium ion, 5-azoniaspiro[4.4]nonane ion, tributylmethylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, tetrabutylphosphonium ion, diallyldimethylammonium ion, 1,1-dimethylpiperidinium ion, (2-hydroxyethyl)dimethyl(3-sulfopropyl)ammonium hydroxide, 3-(trifluoromethyl)phenyltrimethylammonium ion, 1,1'-(decane-1,10-diyl)bis[4-aza-1-azoniabicyclo[2.2.2]octane]diion, (3-bromopropyl)trimethylammonium ion, vinylbenzyltrimethylammonium ion, allyltrimethylammonium ion Examples of the cations include cations, trimethylvinylammonium ions, choline ions, β-methylcholine ions, triphenylsulfonium ions, ethyltrimethylammonium, and propyltrimethylammonium, and preferably, one or more selected from the group consisting of benzyldimethylphenylammonium ions, (1-ethoxy-1-oxopropan-2-yl)triphenylphosphonium ions, 1,1'-(decane-1,10-diyl)bis[4-aza-1-azoniabicyclo[2.2.2]octane]diions, butyltriphenylphosphonium ions, (2-carboxyethyl)triphenylphosphonium ions, (3-carboxypropyl)triphenylphosphonium ions, (4-carboxybutyl)triphenylphosphonium ions, allyltriphenylphosphonium ions, tetraphenylphosphonium ions, and benzyltriphenylphosphonium ions.
　上述のように、オニウムイオンの効果は、残渣除去時の表面荒れの抑制、ＲｕＯ４ガスの抑制が挙げられるが、これに加えて、半導体残渣除去液として用いた場合の再利用回数を向上させる効果もある。半導体ウエハの製造所では、コスト削減の観点から、使用済みの残渣除去液を循環濾過して再利用する事がある。この場合、例えば残渣除去後には、金属が残渣除去液に溶けだすため、使用前と使用後では残渣除去液の組成は異なる。次亜臭素酸イオンによるルテニウムの残渣除去を例に説明すると、ルテニウムはアルカリ性条件下ではＲｕＯ４ －として溶けだす。この場合、このＲｕＯ４ －もしくはＲｕＯ４ －が変化して生成されたＲｕＯ４ ２－やＲｕＯ４と、次亜臭素酸イオンが反応すると、残渣除去に有効な化学種である次亜臭素酸イオン濃度が低下する。そのため、残渣除去液の再利用回数が多くなるほど、また、再利用時間が長くなるほど、残渣除去率は低下する。 As described above, the effects of onium ions include suppressing surface roughness during residue removal and suppressing RuO 4 gas, but in addition to this, they also have the effect of improving the number of times of reuse when used as a semiconductor residue removal solution. In semiconductor wafer manufacturing plants, from the viewpoint of cost reduction, used residue removal solutions are sometimes recycled through circulation filtration. In this case, for example, after residue removal, metals dissolve into the residue removal solution, so the composition of the residue removal solution differs before and after use. Taking the example of ruthenium residue removal using hypobromite ions, ruthenium dissolves as RuO 4 - under alkaline conditions. In this case, when hypobromite ions react with RuO 4 - or RuO 4 2- or RuO 4 generated by changing RuO 4 - , the concentration of hypobromite ions, which are chemical species effective for residue removal, decreases. Therefore, the more times the residue removal solution is reused and the longer the reuse time, the lower the residue removal rate.
　しかし、残渣除去液にオニウムイオンを含ませる事で、再利用時の安定性を改善できる場合がある。すなわち、ＲｕＯ４ －等がオニウムイオンと積極的に反応する事で、ＲｕＯ４ －等と次亜臭素酸イオンの反応を抑制する事が可能となる。このような目的に用いる事ができるオニウムイオンとしては、ホスホニウムイオンである事が好ましい。アンモニウムイオンの場合、次亜臭素酸イオンとの反応により、アミンが生成される懸念があるため、このアミンが次亜臭素酸イオンを分解する可能性がある。また、一般的にアンモニウムイオンよりもホスホニウムイオンの方が分子サイズは大きく、溶解により発生したＲｕＯ４ －とイオン対を形成しやすいため、ＲｕＯ４ －を束縛する事でＲｕＯ４ －と次亜臭素酸イオンとの反応を抑制する効果も得られる。 However, by adding an onium ion to the residue removal solution, the stability during reuse may be improved. That is, RuO 4 - and the like react positively with the onium ion, and it becomes possible to suppress the reaction between RuO 4 - and the like and hypobromite ion. As an onium ion that can be used for such a purpose, a phosphonium ion is preferable. In the case of ammonium ion, there is a concern that an amine may be generated by reaction with hypobromite ion, and this amine may decompose hypobromite ion. In addition, since phosphonium ions generally have a larger molecular size than ammonium ions and are more likely to form an ion pair with RuO 4 - generated by dissolution, binding RuO 4 - also has the effect of suppressing the reaction between RuO 4 - and hypobromite ion.
　また、残渣除去液がオニウムイオンを含み、残渣除去液の表面張力が６０ｍＮ／ｍ以上７５ｍＮ／ｍ以下であることが好ましい。なお、表面張力は２５℃での値である。
　残渣除去液の表面張力が６０ｍＮ／ｍ以上であることで、オニウムイオンが半導体ウエハの金属表面と相互作用する事で、金属表面の荒れを抑制する事が可能となる。一方で、本発明の残渣除去液には酸化剤が含まれるので、酸化剤の安定性が低下したり、残渣除去の阻害が生じる事を防ぐために、表面張力は７５ｍＮ／ｍ以下である事が好ましい。
　残渣除去液の表面張力を増加させる方法の一つとして、水和度の大きいアニオンを含む塩を添加する方法が挙げられる。水和度の大きいアニオンを加えることで、アニオンによるオニウムイオンの電荷の中和が阻害され、オニウムイオン同士の電気的な反発が維持されるため表面張力を増加させることができる。水和度の大きいアニオンとしては、フッ化物イオンや塩化物イオン、臭化物イオンが挙げられる。
　表面張力の測定はＪＩＳ２２４１の「ウィルヘルミー表面張力計による試験方法」に準じて実施することができる。 It is also preferable that the residue removing liquid contains onium ions and has a surface tension of 60 mN/m or more and 75 mN/m or less. Note that the surface tension is measured at 25° C.
By setting the surface tension of the residue removing solution to 60 mN/m or more, the onium ions interact with the metal surface of the semiconductor wafer, making it possible to suppress roughness of the metal surface. On the other hand, since the residue removing solution of the present invention contains an oxidizing agent, in order to prevent the stability of the oxidizing agent from decreasing and the inhibition of residue removal from occurring, the surface tension is preferably set to 75 mN/m or less.
One method for increasing the surface tension of the residue removal solution is to add a salt containing an anion with a high degree of hydration. By adding an anion with a high degree of hydration, the neutralization of the charge of the onium ion by the anion is inhibited, and the electrical repulsion between the onium ions is maintained, thereby increasing the surface tension. Examples of anions with a high degree of hydration include fluoride ions, chloride ions, and bromide ions.
The surface tension can be measured in accordance with JIS 2241 "Test method using a Wilhelmy surface tensiometer."
　このようなオニウムイオンを例示すれば、アリルトリフェニルホスホニウムイオン、テトラフェニルホスホニウムイオン、ｔｒａｎｓ－２－ブテン－１，４－ビス（トリフェニルホスホニウムイオン）、ベンジルトリフェニルホスホニウムイオン、テトラブチルホスホニウムイオン、トリブチルヘキシルホスホニウムイオン、ヘプチルトリフェニルホスホニウムイオン、シクロプロピルトリフェニルホスホニウムイオン、（ブロモメチル）トリフェニルホスホニウムイオン、（クロロメチル）トリフェニルホスホニウムイオン等が挙げられる。 Examples of such onium ions include allyltriphenylphosphonium ion, tetraphenylphosphonium ion, trans-2-butene-1,4-bis(triphenylphosphonium ion), benzyltriphenylphosphonium ion, tetrabutylphosphonium ion, tributylhexylphosphonium ion, heptyltriphenylphosphonium ion, cyclopropyltriphenylphosphonium ion, (bromomethyl)triphenylphosphonium ion, (chloromethyl)triphenylphosphonium ion, etc.
（被処理物がルテニウムの場合）
　本発明において被処理物の一例であるルテニウム（Ｒｕ）としては、ルテニウム系金属とルテニウム合金である場合がある。
　被処理物がルテニウム系金属であり、且つｐＨが２５℃で９.５以上１４以下であるとき、有害なＲｕＯ４ガスが発生しにくく、ＲｕＯ２によるパーティクルも少ない。
　次亜臭素酸イオン、次亜塩素酸イオンがルテニウムを溶解するメカニズムの詳細は必ずしも明らかでないが、残渣除去液中で次亜臭素酸イオン又は次亜臭素酸イオンから生じた次亜臭素酸、あるいは次亜塩素酸イオン又は次亜塩素酸イオンから生じた次亜塩素酸がルテニウムを酸化し、ＲｕＯ４、ＲｕＯ４ －またはＲｕＯ４ ２－とすることで残渣除去液中に溶解していると推測している。ルテニウムをＲｕＯ４ －またはＲｕＯ４ ２－として溶解することで、ＲｕＯ４ガスの発生量を低減し、ＲｕＯ２パーティクルの発生を抑制することが可能となる。ルテニウムをＲｕＯ４ －またはＲｕＯ４ ２－として溶解するためには、残渣除去液のｐＨが９．５以上１４以下であることが好ましく、ｐＨが１２以上１４以下であることがより好ましく、ｐＨが１２以上１３未満であることが最も好ましい。残渣除去液のｐＨが１２以上１３未満であれば、ルテニウムはＲｕＯ４ －またはＲｕＯ４ ２－として残渣除去液中に溶解するため、ＲｕＯ４ガスの発生量を大幅に低減し、ＲｕＯ２パーティクルの発生を抑制することができる。一方、残渣除去液のｐＨが８未満である場合、ルテニウムはＲｕＯ２やＲｕＯ４に酸化されやすくなるため、ＲｕＯ２パーティクル量が増加するとともに、ＲｕＯ４ガス発生量が増大する傾向にある。また、ｐＨが１４を超えるとルテニウムの溶解が生じにくくなり、十分なルテニウムエッチング速度を得ることが難しくなるため、半導体製造における生産効率が低下する。なお、上記で例示するｐＨはいずれも２５℃での値である。 (When the object to be treated is ruthenium)
Ruthenium (Ru), which is an example of the object to be treated in the present invention, may be a ruthenium-based metal or a ruthenium alloy.
When the material to be treated is a ruthenium-based metal and the pH is 9.5 or more and 14 or less at 25° C., harmful RuO 4 gas is unlikely to be generated and particles due to RuO 2 are also few.
Although the details of the mechanism by which hypobromite ions and hypochlorite ions dissolve ruthenium are not necessarily clear, it is presumed that hypobromite ions or hypobromous acid generated from hypobromite ions in the residue removal solution, or hypochlorite ions or hypochlorite ions generated from hypochlorite ions in the residue removal solution, oxidize ruthenium to RuO 4 , RuO 4 - or RuO 4 2- , and dissolve in the residue removal solution. By dissolving ruthenium as RuO 4 - or RuO 4 2- , it is possible to reduce the amount of RuO 4 gas generated and suppress the generation of RuO 2 particles. In order to dissolve ruthenium as RuO 4 - or RuO 4 2- , the pH of the residue removal solution is preferably 9.5 or more and 14 or less, more preferably 12 or more and 14 or less, and most preferably 12 or more and less than 13. If the pH of the residue removing solution is 12 or more but less than 13, ruthenium dissolves in the residue removing solution as RuO 4 - or RuO 4 2- , so that the amount of RuO 4 gas generated can be significantly reduced and the generation of RuO 2 particles can be suppressed. On the other hand, if the pH of the residue removing solution is less than 8, ruthenium is easily oxidized to RuO 2 or RuO 4 , so that the amount of RuO 2 particles increases and the amount of RuO 4 gas generated tends to increase. In addition, if the pH exceeds 14, it becomes difficult to dissolve ruthenium, and it becomes difficult to obtain a sufficient ruthenium etching rate, so that the production efficiency in semiconductor manufacturing decreases. Note that all of the pH values exemplified above are values at 25°C.
　ここで「ルテニウム系金属」とは、金属ルテニウムのほか、ルテニウムを７０原子％以上含有するルテニウム金属、ルテニウムの酸化物（ＲｕＯＸ）、窒化物（ＲｕＮ）、酸窒化物（ＲｕＮＯ）等を指す。ここでルテニウムの酸化物は、二酸化ルテニウム、三酸化二ルテニウム（三水和物）のことである。また、本発明において「ルテニウム合金」とは、ルテニウムを７０原子％以上９９．９９原子％以下含有し、かつ不可避的に含有される濃度より高い濃度のルテニウム以外の金属を含む合金を指す。本発明において、ルテニウム系金属とルテニウム合金を特に区別する必要のないときは、これらをルテニウムと記載する。 Here, "ruthenium-based metal" refers to ruthenium metal containing 70 atomic % or more of ruthenium, ruthenium oxide ( RuOx ), nitride (RuN), oxynitride (RuNO), etc. Here, ruthenium oxide refers to ruthenium dioxide and ruthenium trioxide (trihydrate). In addition, in the present invention, "ruthenium alloy" refers to an alloy containing 70 atomic % or more and 99.99 atomic % or less of ruthenium and containing a metal other than ruthenium at a concentration higher than the concentration that is inevitably contained. In the present invention, when there is no need to particularly distinguish between ruthenium-based metal and ruthenium alloy, they are described as ruthenium.
　ルテニウム合金は、ルテニウムの他にどのような金属を含んでいてもよいが、ルテニウム合金に含まれる金属の一例を挙げれば、タンタル、シリコン、銅、ハフニウム、ジルコニウム、アルミニウム、バナジウム、コバルト、ニッケル、マンガン、金、ロジウム、パラジウム、チタン、タングステン、モリブデン、白金、イリジウムなどが挙げられ、これらの酸化物、窒化物、シリサイドを含んでいてもよい。
　これらのルテニウムは、金属間化合物や、イオン性化合物、錯体であってもよい。また、ルテニウムはウエハの表面に露出していてもよいし、他の金属や金属酸化膜、絶縁膜、レジスト等に覆われていてもよい。他の材料に覆われている場合であっても、ルテニウムが本発明の残渣除去液に接触してルテニウムの溶解が起こる際、ＲｕＯ４ガス発生抑制効果が発揮される。さらに、本発明の残渣除去液は、ルテニウムを積極的に溶解させない場合、すなわち、ルテニウムが保護の対象である処理であっても、極僅かに溶解したルテニウムから発生するＲｕＯ４ガスを抑制する事が可能である。 The ruthenium alloy may contain any metal other than ruthenium. Examples of metals contained in the ruthenium alloy include tantalum, silicon, copper, hafnium, zirconium, aluminum, vanadium, cobalt, nickel, manganese, gold, rhodium, palladium, titanium, tungsten, molybdenum, platinum, and iridium, and the alloy may contain oxides, nitrides, and silicides of these metals.
These ruthenium compounds may be intermetallic compounds, ionic compounds, or complexes. Ruthenium may be exposed on the surface of the wafer, or may be covered with other metals, metal oxide films, insulating films, resists, or the like. Even if covered with other materials, when ruthenium comes into contact with the residue removing solution of the present invention and dissolution of ruthenium occurs, the RuO4 gas generation suppression effect is exerted. Furthermore, the residue removing solution of the present invention can suppress RuO4 gas generated from very small amounts of dissolved ruthenium even in the case where ruthenium is not actively dissolved, that is, even in the case of a process in which ruthenium is the object of protection.
（半導体デバイスの製造方法）
　本発明の半導体デバイスの製造方法は、半導体ウエハをドライエッチングする工程、及び、上記のドライエッチング残渣除去液によりドライエッチング残渣を除去する工程を含む。さらに、半導体ウエハをドライエッチングする工程の前に、半導体基板に金属膜を形成して半導体ウエハを形成する金属膜形成工程を含んでもよく、ドライエッチング残渣を除去する工程の前及び／または後に、半導体ウエハをリンスする工程と、半導体ウエハを乾燥させる工程を含んでもよい。
　半導体ウエハをドライエッチングする工程（半導体基板上の金属膜をドライエッチングする工程）の後に、ドライエッチング残渣除去液を使用することにより、ドライエッチングのみで処理した際に比べ、より高効率で残渣を除去できる。さらに、ウェットエッチングのみで処理した際に比べ、金属膜表面の表面平滑性を損なわずに処理することが可能である。
　半導体ウエハをリンスする工程ではリンス液を半導体ウエハと接触させる事で、半導体ウエハの洗浄を行うことができる。リンス液は、水、オゾン水、ラジカル水、電解イオン水等の機能水、２－プロパノール等の有機溶剤、アンモニア過酸化水素混合液、塩酸過酸化水素混合液、硫酸過酸化水素混合液、硝酸フッ酸混合液、フッ酸、硫酸、リン酸、硝酸、バッファードフッ酸、アンモニア、過酸化水素、塩酸、水酸化テトラメチルアンモニウム（ＴＭＡＨ）およびこれらと水との混合液からなる群より選ぶことができる。
　半導体ウエハを乾燥させる工程では特に制限はされないが、スピン乾燥、ＩＰＡ乾燥、マランゴニ乾燥、ロタゴニ乾燥などで乾燥を行うことができる。
　また、半導体デバイスの製造方法は、ウエハ作製工程、酸化膜形成工程、トランジスタ形成工程、配線形成工程およびＣＭＰ工程から選択される１以上の工程など、半導体デバイスの製造方法に用いられる公知の工程を含んでもよい。 (Method of manufacturing semiconductor devices)
The method for producing a semiconductor device of the present invention includes a step of dry etching a semiconductor wafer, and a step of removing dry etching residues with the above-mentioned dry etching residue removing solution. Furthermore, the method may include a metal film forming step of forming a semiconductor wafer by forming a metal film on a semiconductor substrate before the step of dry etching the semiconductor wafer, and may include a step of rinsing the semiconductor wafer and a step of drying the semiconductor wafer before and/or after the step of removing the dry etching residues.
By using the dry etching residue remover after the process of dry etching a semiconductor wafer (the process of dry etching a metal film on a semiconductor substrate), the residue can be removed more efficiently than when only dry etching is used. Furthermore, compared to when only wet etching is used, the surface smoothness of the metal film can be maintained.
In the process of rinsing the semiconductor wafer, the semiconductor wafer can be cleaned by contacting the semiconductor wafer with a rinsing liquid. The rinsing liquid can be selected from the group consisting of water, functional water such as ozone water, radical water, and electrolytic ion water, organic solvents such as 2-propanol, ammonia-hydrogen peroxide mixtures, hydrochloric acid-hydrogen peroxide mixtures, sulfuric acid-hydrogen peroxide mixtures, nitric acid-hydrofluoric acid mixtures, hydrofluoric acid, sulfuric acid, phosphoric acid, nitric acid, buffered hydrofluoric acid, ammonia, hydrogen peroxide, hydrochloric acid, tetramethylammonium hydroxide (TMAH), and mixtures of these with water.
The step of drying the semiconductor wafer is not particularly limited, but the drying can be performed by spin drying, IPA drying, Marangoni drying, Rotagoni drying, or the like.
The method for manufacturing a semiconductor device may also include known steps used in the manufacture of semiconductor devices, such as one or more steps selected from a wafer fabrication step, an oxide film formation step, a transistor formation step, a wiring formation step, and a CMP step.
　上記ドライエッチングが行われる基板は、遷移金属を含む半導体ウエハである。基板上に遷移金属膜はいかなる方法により形成されていてもよく、例えばＣＶＤ、ＡＬＤ、ＰＶＤ、スパッタ、めっき等を利用できる。
　上述の方法で作成された遷移金属を含む半導体ウエハをドライエッチングする場合、ドライエッチングの方法は特に制限されず、公知の方法により行うことができるが、Ｏ２／Ｃｌ２混合ガスを用いてドライエッチングするのが好適である。
　ドライエッチングは反応性イオンエッチング（Ｒｅａｃｔｉｖｅ　Ｉｏｎ　Ｅｔｃｈｉｎｇ）が好ましい。また、反応性イオンエッチングのプラズマを発生法としては容量結合型（Ｃａｐａｃｉｔｉｖｅ　Ｃｏｕｐｌｅｄ　Ｐｌａｓｍａ－ＲＩＥ）、誘導結合型（Ｉｎｄｕｃｔｉｖｅ　Ｃｏｕｐｌｅｄ　Ｐｌａｓｍａ－ＲＩＥ）、ＥＣＲ型（Ｅｌｅｃｔｒｏｎ　Ｃｙｃｌｏｔｒｏｎ　Ｒｅｓｏｎａｎｃｅ－ＲＩＥ）が好ましい。
　上記の方法でドライエッチングを実施すると、Ｓｉ含有残渣物、金属含有残渣物、及び、フォトレジスト由来の有機物含有残渣物等のドライエッチング残渣が発生する。本発明の残渣除去液はこれらのドライエッチング残渣の除去に好適に用いられる。 The substrate on which the dry etching is performed is a semiconductor wafer containing a transition metal. The transition metal film may be formed on the substrate by any method, such as CVD, ALD, PVD, sputtering, plating, etc.
When dry etching the semiconductor wafer containing a transition metal produced by the above-mentioned method, the dry etching method is not particularly limited and can be performed by a known method, but it is preferable to dry etch using an O 2 /Cl 2 mixed gas.
The dry etching is preferably reactive ion etching. As a method for generating plasma for reactive ion etching, capacitive coupled plasma-RIE, inductive coupled plasma-RIE, or ECR (Electron Cyclotron Resonance-RIE) is preferable.
When dry etching is performed by the above method, dry etching residues such as Si-containing residues, metal-containing residues, and organic substance-containing residues derived from photoresist are generated. The residue removing solution of the present invention is suitably used for removing these dry etching residues.
（半導体ウエハのドライエッチング残渣除去方法、半導体ウエハの洗浄方法）
　本発明の残渣除去液は、半導体ウエハと接触させる事で、半導体ウエハのドライエッチング残渣除去を行うことができる。つまり本発明の半導体ウエハのドライエッチング残渣除去方法は、上記残渣除去液と半導体ウエハとを接触させる工程を含む。 (Method for removing dry etching residue from semiconductor wafer, method for cleaning semiconductor wafer)
The residue-removing solution of the present invention can remove dry etching residues from a semiconductor wafer by contacting the semiconductor wafer. That is, the method for removing dry etching residues from a semiconductor wafer of the present invention includes a step of contacting the semiconductor wafer with the residue-removing solution.
　また、本発明のドライエッチング残渣除去方法は、半導体ウエハの洗浄方法としても利用できる。半導体ウエハの洗浄方法についても、ドライエッチング残渣除去方法と同様に、上記の残渣除去液と半導体ウエハを接触させる工程を含む。
　ドライエッチング残渣除去方法または半導体ウエハの洗浄方法において、残渣除去液と半導体ウエハを接触させる方法は特に制限されず、使用する洗浄装置の洗浄条件や使用される半導体ウエハに合わせて適宜選択すればよい。例えば、残渣除去液を半導体ウエハに噴霧する方法、残渣除去液の入った容器に半導体ウエハを浸漬する方法、半導体ウエハ上に残渣除去液を滴下する方法、半導体ウエハに残渣除去液を接触させ超音波をかけることで残渣除去を促進させる方法、及び、それらの任意の組み合わせが挙げられる。
　本発明の残渣除去液を使用する温度は、１０～８０℃、好ましくは２０～７０℃の範囲であり、使用する洗浄装置の洗浄条件や使用される半導体ウエハに合わせて適宜選択されればよい。
　本発明の残渣除去液を使用する時間は、ウエハ１枚当たり０．１～１２０分、好ましくは０．５～６０分であり、使用する洗浄装置の洗浄条件や使用される半導体ウエハに合わせて適宜選択されればよい。 The method for removing dry etching residues of the present invention can also be used as a method for cleaning semiconductor wafers. The method for cleaning semiconductor wafers also includes a step of contacting the semiconductor wafer with the above-mentioned residue removing solution, similar to the method for removing dry etching residues.
In the method for removing dry etching residues or the method for cleaning a semiconductor wafer, the method for bringing the semiconductor wafer into contact with the residue-removing liquid is not particularly limited, and may be appropriately selected according to the cleaning conditions of the cleaning device used and the semiconductor wafer used. For example, there may be mentioned a method of spraying the residue-removing liquid onto the semiconductor wafer, a method of immersing the semiconductor wafer in a container containing the residue-removing liquid, a method of dripping the residue-removing liquid onto the semiconductor wafer, a method of bringing the semiconductor wafer into contact with the residue-removing liquid and applying ultrasonic waves to promote residue removal, and any combination thereof.
The temperature at which the residue removing solution of the present invention is used is in the range of 10 to 80° C., preferably 20 to 70° C., and may be appropriately selected depending on the cleaning conditions of the cleaning device used and the semiconductor wafer used.
The time for which the residue removing solution of the present invention is used is 0.1 to 120 minutes, preferably 0.5 to 60 minutes, per wafer, and may be appropriately selected according to the cleaning conditions of the cleaning device used and the semiconductor wafer used.
　（保管容器）
　本発明の残渣除去液を保管する容器は特に制限されないが、容器からの不純物の溶出が少ないクリーン度の高い容器であることが好ましく、金属成分の溶出が少ないことから、液と接触する容器内面は有機高分子材料であることが好ましい。容器内面に使用する有機高分子材料としては、塩化ビニル系樹脂（軟質・硬質塩化ビニル樹脂）、ナイロン系樹脂、シリコーン系樹脂、ポリオレフィン系樹脂（ポリエチレン、ポリプロピレン）、フッ素樹脂等を使用できる、中でも、成型のしやすさ、耐溶剤性、不純物の溶出が少ないもの等を考慮すると、ポリオレフィン系樹脂またはフッ素系樹脂が好ましい。 (Storage container)
The container for storing the residue removing liquid of the present invention is not particularly limited, but it is preferable that the container is highly clean and that impurities are less likely to be eluted from the container, and the inner surface of the container that comes into contact with the liquid is preferably made of an organic polymer material because it is less likely to elute metal components. As the organic polymer material used for the inner surface of the container, vinyl chloride resins (soft and hard vinyl chloride resins), nylon resins, silicone resins, polyolefin resins (polyethylene, polypropylene), fluororesins, etc. can be used, and among them, polyolefin resins or fluororesins are preferable in consideration of ease of molding, solvent resistance, and less elution of impurities.
　以下、実施例によって本発明をさらに具体的に説明するが、本発明はこれらの実施例に制限されるものではない。 The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.
（半導体デバイスの製造）
　まず、シリコンからなる基板を用意した。用意した基板に対して、酸化処理を行い、シリコン上に酸化シリコン膜を５００ｎｍ形成した。その後、低誘電率（Ｌｏｗ－ｋ）膜からなる層間絶縁膜５０ｎｍを成膜し、層間絶縁膜上にフォトレジスト膜を成膜し、層間絶縁膜にビアホールを形成した。形成されたビアホールにルテニウム膜を２０ｎｍ成膜した。 (Semiconductor device manufacturing)
First, a substrate made of silicon was prepared. The prepared substrate was subjected to an oxidation treatment to form a silicon oxide film of 500 nm on the silicon. Then, an interlayer insulating film of 50 nm made of a low dielectric constant (Low-k) film was formed, a photoresist film was formed on the interlayer insulating film, and a via hole was formed in the interlayer insulating film. A ruthenium film of 20 nm was formed in the formed via hole.
　上記方法にてルテニウム膜を成膜した被処理物（半導体基板）に対して、反応性イオンエッチング装置（Ｓａｍｃｏ社製ＲＩＥ－４００ＩＰＣ）でドライエッチング処理を施した。
　上記方法にてドライエッチングした被処理物を、１０×２０ｍｍに割断した。ドライエッチング残渣除去液６０ｍＬを、蓋付きフッ素樹脂製容器（ＡｓＯｎｅ社製、ＰＦＡ容器９４．０ｍＬ）に準備した。上記手法により作製したドライエッチング後の被処理物を、ドライエッチング残渣除去液中に３０℃で１分間浸漬した。
　超純水６０ｍＬを、蓋付きフッ素樹脂製容器（ＡｓＯｎｅ社製、ＰＦＡ容器９４．０ｍＬ）に準備した。上記手法により作製したドライエッチング残渣除去処理後の半導体ウエハを、超純水中に３０℃で１分間浸漬した。
　上記方法にて得られた半導体被処理物に対して乾燥窒素を吹き付けることで超純水を除去した。 The workpiece (semiconductor substrate) on which the ruthenium film was formed by the above method was subjected to dry etching treatment using a reactive ion etching apparatus (RIE-400IPC manufactured by Samco Corporation).
The workpiece dry-etched by the above method was cut into 10 x 20 mm pieces. 60 mL of the dry etching residue removal solution was prepared in a fluororesin container with a lid (AsOne, PFA container 94.0 mL). The workpiece after dry etching prepared by the above method was immersed in the dry etching residue removal solution at 30°C for 1 minute.
60 mL of ultrapure water was prepared in a fluororesin container with a lid (AsOne Corp., PFA container 94.0 mL). The semiconductor wafer after the dry etching residue removal process produced by the above method was immersed in the ultrapure water at 30° C. for 1 minute.
Dry nitrogen was sprayed onto the semiconductor workpiece obtained by the above method to remove ultrapure water.
（残渣除去液によるドライエッチング残渣除去率の評価）
　上記方法にて作製したドライエッチング処理後の被処理物を、透過型電子顕微鏡（ＴＥＭ）を用いて観察した。得られた画像からドライエッチング残渣物の個数αを数えた。次に、ドライエッチング残渣除去液６０ｍＬを、蓋付きフッ素樹脂製容器（ＡｓＯｎｅ社製、ＰＦＡ容器９４．０ｍＬ）に準備した。上記手法により作製した被処理物を、ドライエッチング残渣除去液中に３０℃で１分間浸漬した。次に、ドライエッチング残渣除去によって処理された被処理物をＴＥＭを用いて観察した。得られた画像からドライエッチング残渣物の個数βを数えた。この観察によって得られたドライエッチング残渣物の個数α、βから、残渣除去率Ｘ（％）をＸ＝（α―β）／α×１００の式より算出し、下記の基準で評価した。いずれも評価Ａ～Ｃが許容レベル、評価Ｄが不可レベルとした。 (Evaluation of Dry Etching Residue Removal Rate by Residue Removal Solution)
The workpiece after the dry etching process prepared by the above method was observed using a transmission electron microscope (TEM). The number of dry etching residues α was counted from the obtained image. Next, 60 mL of dry etching residue removal solution was prepared in a fluororesin container with a lid (AsOne, PFA container 94.0 mL). The workpiece prepared by the above method was immersed in the dry etching residue removal solution at 30° C. for 1 minute. Next, the workpiece treated by the dry etching residue removal was observed using a TEM. The number of dry etching residues β was counted from the obtained image. From the numbers α and β of dry etching residues obtained by this observation, the residue removal rate X (%) was calculated by the formula X = (α - β) / α × 100, and was evaluated according to the following criteria. In both cases, evaluations A to C were considered to be acceptable levels, and evaluation D was considered to be unacceptable levels.
評価：
Ａ：９０％以上
Ｂ：７０％以上９０％未満
Ｃ：５０％以上７０％未満（許容レベル）
Ｄ：５０％未満 evaluation:
A: 90% or more B: 70% or more but less than 90% C: 50% or more but less than 70% (acceptable level)
D: Less than 50%
　（ＲｕＯ４ガスの定量分析）
　ＲｕＯ４ガスの発生量は、ＩＣＰ－ＯＥＳを用いて測定した。密閉容器に、ドライエッチング残渣除去液を５ｍＬとり、膜厚１２０ｎｍのルテニウム膜を成膜した１０×２０ｍｍのルテニウム膜１枚を、３０℃でルテニウムが全て溶解するまで浸漬させた。その後、密閉容器にＡｉｒをフローし、密閉容器内の気相を吸収液（１ｍｏｌ／Ｌ　ＮａＯＨ）の入った容器にバブリングして、浸漬中に発生したＲｕＯ４ガスを吸収液にトラップした。ドライエッチング残渣除去液に浸漬したＳｉウエハ上のルテニウムが全て溶解したことは、四探針抵抗測定器（ロレスタ－ＧＰ、三菱ケミカルアナリテック社製）により浸漬前および浸漬後のシート抵抗をそれぞれ測定し、膜厚に換算する事で確認した。吸収液中のルテニウム量をＩＣＰ－ＯＥＳ（ｉＣＡＰ６５００　ＤＵＯ、サーモフィッシャーサイエンティフィック社製）により測定し、ＲｕＯ４ガス量に換算し、下記の基準で評価した。いずれも評価Ａ～Ｃが許容レベル、評価Ｄが不可レベルとした。 (Quantitative analysis of RuO4 gas)
The amount of RuO 4 gas generated was measured using ICP-OES. 5 mL of the dry etching residue removal solution was placed in a sealed container, and one 10×20 mm ruthenium film having a thickness of 120 nm was immersed at 30° C. until all of the ruthenium was dissolved. Thereafter, air was flowed into the sealed container, and the gas phase in the sealed container was bubbled into a container containing an absorbing solution (1 mol/L NaOH), and the RuO 4 gas generated during immersion was trapped in the absorbing solution. The fact that all of the ruthenium on the Si wafer immersed in the dry etching residue removal solution was dissolved was confirmed by measuring the sheet resistance before and after immersion using a four-point probe resistance meter (Loresta GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) and converting it into a film thickness. The amount of ruthenium in the absorption solution was measured by ICP-OES (iCAP6500 DUO, manufactured by Thermo Fisher Scientific), converted into the amount of RuO4 gas, and evaluated according to the following criteria. In each case, ratings A to C were acceptable levels, and rating D was unacceptable.
評価：
Ａ：＜５μｇ／ｃｍ２
Ｂ：５～１０μｇ／ｃｍ２未満
Ｃ：１０μｇ／ｃｍ２～４０μｇ／ｃｍ２以下（許容レベル）
Ｄ：＞４０μｇ／ｃｍ２ evaluation:
A: <5 μg/ cm2
B: 5 to less than 10 μg/ cm2 C: 10 μg/ cm2 to 40 μg/ cm2 or less (acceptable level)
D: >40 μg/ cm2
（残渣除去液中の酸化剤の保存安定性評価）
　残渣除去液中の酸化剤の保存安定性評価は、紫外可視分光光度計（ＵＶ－２６００、島津製作所社製）を用いて測定した。ドライエッチング残渣除去液５Ｌを、遮光ピュアボトル（コダマ樹脂工業社製、ＰＦＡ容器５Ｌ）に準備し、２５℃で遮光しながら保存した。その後、ドライエッチング残渣除去液中の酸化剤濃度を定期的に紫外可視分光光度計（ＵＶ－２６００、島津製作所社製）を用いて６ヶ月間測定した。製造直後の酸化剤濃度を１００％とし、６か月後のドライエッチング残渣除去液中の酸化剤濃度を、下記の基準で評価した。いずれも評価Ａ～Ｃが許容レベル、評価Ｄが不可レベルとした。 (Evaluation of storage stability of oxidizing agent in residue removal solution)
The storage stability evaluation of the oxidizing agent in the residue removal solution was measured using an ultraviolet-visible spectrophotometer (UV-2600, manufactured by Shimadzu Corporation). 5 L of the dry etching residue removal solution was prepared in a light-shielding pure bottle (manufactured by Kodama Resin Industry Co., Ltd., PFA container 5 L) and stored at 25°C while being shielded from light. Thereafter, the oxidizing agent concentration in the dry etching residue removal solution was periodically measured for 6 months using an ultraviolet-visible spectrophotometer (UV-2600, manufactured by Shimadzu Corporation). The oxidizing agent concentration immediately after production was set to 100%, and the oxidizing agent concentration in the dry etching residue removal solution after 6 months was evaluated according to the following criteria. In both cases, evaluations A to C were considered to be acceptable levels, and evaluation D was considered to be unacceptable levels.
評価：
Ａ：９５％以上
Ｂ：９０以上９５％未満
Ｃ：８５以上９０％未満（許容レベル）
Ｄ：８５％未満 evaluation:
A: 95% or more B: 90% or more but less than 95% C: 85% or more but less than 90% (acceptable level)
D: Less than 85%
（エッチング後の表面平滑性の評価）
　ドライエッチング残渣除去液６０ｍＬを、蓋付きフッ素樹脂製容器（ＡｓＯｎｅ社製、ＰＦＡ容器９４．０ｍＬ）に準備し、上記方法にて作製したドライエッチング処理前の被処理物をドライエッチング残渣除去液中に３０℃で１分間浸漬し、エッチングした。その後、電界放射型走査電子顕微鏡（ＪＳＭ－７８００Ｆ　Ｐｒｉｍｅ、日本電子社製）によりエッチング前とエッチング後のルテニウム表面を観察し、表面荒れの有無を確認し、下記の基準で評価した。表面荒れが少ない順にＡ～Ｄとなっており、いずれも評価Ａ～Ｃが許容レベル、評価Ｄが許容不可レベルとした。
　Ａ：表面荒れは見られない
　Ｂ：表面荒れが若干見られる
　Ｃ：表面全体に荒れは見られるが、荒れが浅い
　Ｄ：表面全体に荒れが見られ、かつ荒れが深い (Evaluation of surface smoothness after etching)
60 mL of the dry etching residue removing solution was prepared in a fluororesin container with a lid (AsOne, PFA container 94.0 mL), and the workpiece before dry etching prepared by the above method was immersed in the dry etching residue removing solution for 1 minute at 30°C and etched. Thereafter, the ruthenium surface before and after etching was observed with a field emission scanning electron microscope (JSM-7800F Prime, JEOL Ltd.) to confirm the presence or absence of surface roughness and evaluate it according to the following criteria. The order of surface roughness is A to D, with A to C being acceptable levels and D being unacceptable levels.
A: No surface roughness is observed. B: Some surface roughness is observed. C: Roughness is observed over the entire surface, but the roughness is shallow. D: Roughness is observed over the entire surface, and the roughness is deep.
（残渣除去液の製造）
　２Ｌのガラス製三ツ口フラスコ（コスモスビード社製）に２５質量％の水酸化テトラメチルアンモニウム水溶液２０９ｇ、超純水７９１ｇを混合して、ＣＯ２含有量が０．５ｐｐｍであり、５．２質量％の水酸化テトラメチルアンモニウム水溶液を得た。このときのｐＨは１３．８であった。
　次いで、三ツ口フラスコの内に回転子（ＡｓＯｎｅ社製、全長３０ｍｍ×径８ｍｍ）を入れ、一つの開口部に温度計保護管（コスモスビード社製、底封じ型）と温度計を投入し、もう一つの開口部に塩素ガスボンベ、および窒素ガスボンベに接続され、任意で塩素ガス／窒素ガスの切換えが可能な状態にしたＰＦＡ製チューブ（フロン工業株式会社製、F-８０１１－０２）の先端を該溶液底部に浸漬させ、残りの一つの開口部は５質量％の水酸化ナトリウム水溶液で満たしたガス洗浄瓶（ＡｓＯｎｅ社製、ガス洗浄瓶、型番２４５０／５００）に接続した。次に、二酸化炭素濃度が１ｐｐｍ未満の窒素ガスをＰＦＡ製チューブから、０．２８９Ｐａ・ｍ３／秒（０℃換算時）で２０分間流すことで気相部の二酸化炭素を追いだした。この時、気相部の二酸化炭素濃度は、１ｐｐｍ以下であった。
　その後、マグネットスターラー（ＡｓＯｎｅ社製、Ｃ－ＭＡＧ ＨＳ１０）を三ツ口フラスコ下部に設置して３００ｒｐｍで回転、撹拌し、三ツ口フラスコ外周部を氷水で冷却しながら、塩素ガス（フジオックス社製、仕様純度９９．４％）を０．０５９Ｐａ・ｍ３／秒（０℃換算時）で１８０分間、供給し、次亜塩素酸テトラメチルアンモニウム水溶液（酸化剤；３．５１質量％相当、０．２８ｍｏｌ／Ｌ）と水酸化テトラメチルアンモニウム（０．０９質量％相当、０．００９７ｍｏｌ／Ｌ）の混合溶液を得た。この時、反応中の液温は１１℃であった。
　その後、１００ｍｌＰＦＡボトル（ＡｓＯｎｅ社製、ＡＣＰＦＡ１００－Ｎ）に、水酸化ナトリウム水溶液（０．１ｍｏｌ／Ｌ、和光純薬製）０．１ｇを秤量し、１００ｍｌに希釈する。更に、１００ｍｌＰＦＡボトル（ＡｓＯｎｅ社製、ＡＣＰＦＡ１００－Ｎ）に、上記操作によって得られた希釈液０．１ｇを秤量し、１００ｍｌに希釈する。このようにして金属含有液を得た。
　上記操作により得られた次亜塩素酸テトラメチルアンモニウム溶液、超純水、オニウム塩、テトラメチルアンモニウムヒドロキシド（２５質量％、トクヤマ社製）、塩酸、上記操作により得られた金属含有液を表１～３に記載の濃度になるように加え混合する事で、実施例１９～２９、４０～４２に記載された組成の残渣除去液を得た。なお、残渣除去液中に含まれる金属は上記ドライエッチング残渣除去液に含まれる金属にて記載した金属であり、残渣除去液中の金属濃度は、残渣除去液中に含有されるＭｇ、Ｃａ、Ｎａ、及びＫの合計含有量から算出される濃度である。 (Production of Residue Removal Solution)
209 g of a 25% by mass aqueous solution of tetramethylammonium hydroxide and 791 g of ultrapure water were mixed in a 2 L glass three-neck flask (manufactured by Cosmos Bead Co., Ltd.) to obtain an aqueous solution of tetramethylammonium hydroxide having a CO2 content of 0.5 ppm and a concentration of 5.2% by mass. The pH at this time was 13.8.
Next, a rotor (AsOne, total length 30 mm x diameter 8 mm) was placed in a three-neck flask, a thermometer protection tube (Cosmos Bead, bottom-sealed type) and a thermometer were placed in one opening, a chlorine gas cylinder and a nitrogen gas cylinder were connected to the other opening, and the tip of a PFA tube (Flon Industries, F-8011-02) that was connected to a state in which chlorine gas/nitrogen gas could be switched at will was immersed in the bottom of the solution, and the remaining opening was connected to a gas washing bottle (AsOne, gas washing bottle, model number 2450/500) filled with a 5% by mass aqueous sodium hydroxide solution. Next, nitrogen gas with a carbon dioxide concentration of less than 1 ppm was flowed from the PFA tube at 0.289 Pa·m 3 /sec (at 0°C) for 20 minutes to expel carbon dioxide from the gas phase. At this time, the carbon dioxide concentration in the gas phase was 1 ppm or less.
Thereafter, a magnetic stirrer (AsOne Corp., C-MAG HS10) was placed at the bottom of the three-neck flask and rotated and stirred at 300 rpm, and while the outer periphery of the three-neck flask was cooled with ice water, chlorine gas (Fujiox Corp., specification purity 99.4%) was supplied at 0.059 Pa·m 3 /sec (at 0°C) for 180 minutes to obtain a mixed solution of tetramethylammonium hypochlorite aqueous solution (oxidizing agent; equivalent to 3.51% by mass, 0.28 mol/L) and tetramethylammonium hydroxide (equivalent to 0.09% by mass, 0.0097 mol/L). At this time, the liquid temperature during the reaction was 11°C.
Then, 0.1 g of sodium hydroxide aqueous solution (0.1 mol/L, Wako Pure Chemical Industries, Ltd.) was weighed into a 100 ml PFA bottle (AsOne, ACPFA100-N) and diluted to 100 ml. Furthermore, 0.1 g of the diluted solution obtained by the above operation was weighed into a 100 ml PFA bottle (AsOne, ACPFA100-N) and diluted to 100 ml. In this way, a metal-containing liquid was obtained.
The tetramethylammonium hypochlorite solution obtained by the above operation, ultrapure water, onium salt, tetramethylammonium hydroxide (25% by mass, manufactured by Tokuyama Corporation), hydrochloric acid, and the metal-containing liquid obtained by the above operation were added and mixed to the concentrations shown in Tables 1 to 3 to obtain residue removing solutions having the compositions shown in Examples 19 to 29 and 40 to 42. The metals contained in the residue removing solution are those shown in the metals contained in the dry etching residue removing solution, and the metal concentrations in the residue removing solution are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solution.
　超純水９７．０２ｇへ、上記操作により得られた次亜塩素酸テトラメチルアンモニウム溶液０．０４ｇ、臭化テトラメチルアンモニウム（９７質量％、東京化成工業社製）０．０１ｇ、（１－エトキシー１－オキソプロパンー２－イル）トリフェニルホスホニウムブロミド（９８質量％、東京化成工業社製）０．０５ｇ、テトラメチルアンモニウムヒドロキシド（２５質量％、トクヤマ社製）１．１４ｇ、上記操作により得られた金属含有液１．７４ｇを加え混合する事で、実施例１に記載された組成の残渣除去液を得た。実施例２～１２、３６～３８も同様の方法によって製造し評価を行った。なお、残渣除去液中に含まれる金属は上記ドライエッチング残渣除去液に含まれる金属にて記載した金属であり、残渣除去液中の金属濃度は、残渣除去液中に含有されるＭｇ、Ｃａ、Ｎａ、及びＫの合計含有量から算出される濃度である。 0.04 g of the tetramethylammonium hypochlorite solution obtained by the above operation, 0.01 g of tetramethylammonium bromide (97% by mass, manufactured by Tokyo Chemical Industry Co., Ltd.), 0.05 g of (1-ethoxy-1-oxopropan-2-yl)triphenylphosphonium bromide (98% by mass, manufactured by Tokyo Chemical Industry Co., Ltd.), 1.14 g of tetramethylammonium hydroxide (25% by mass, manufactured by Tokuyama Corporation), and 1.74 g of the metal-containing liquid obtained by the above operation were added to 97.02 g of ultrapure water and mixed to obtain a residue removal solution having the composition described in Example 1. Examples 2 to 12 and 36 to 38 were also manufactured and evaluated in the same manner. The metals contained in the residue removal solution are the metals described in the metals contained in the dry etching residue removal solution, and the metal concentration in the residue removal solution is the concentration calculated from the total content of Mg, Ca, Na, and K contained in the residue removal solution.
　内径４５ｍｍのガラスカラム（ＡｓＯｎｅ製、バイオカラムＣＦ－５０ＴＫ）に、強酸性イオン交換樹脂（オルガノ社製、アンバーライトＩＲ―１２０ＢＮａ）を２００ｍＬ投入した。その後、水素型に交換するため１規定の塩酸（和光純薬工業社製、容量分析用）を１Ｌ、イオン交換樹脂カラムに通液し、イオン交換樹脂を水洗するため、超純水１Ｌを通液した。さらに、水素型に交換されたイオン交換樹脂に、２．３８％水酸化テトラメチルアンモニウム溶液を２Ｌ通液し、水素型からテトラメチルアンモニウム型にイオン交換した。イオン交換後、イオン交換樹脂を水洗するため、超純水１Ｌを通液した。
　超純水へ、市販されている亜臭素酸ナトリウムを加え、亜臭素酸ナトリウム溶液を得た。この亜臭素酸ナトリウム溶液をテトラメチルアンモニウム型にイオン交換したイオン交換樹脂に通液し、ナトリウムイオンをテトラメチルアンモニウムイオンに置換することで亜臭素酸テトラメチルアンモニウム溶液を得た。 200 mL of strong acid ion exchange resin (Amberlite IR-120BNa, Organo Corporation) was placed in a glass column (AsOne, Biocolumn CF-50TK) with an inner diameter of 45 mm. Then, 1 L of 1N hydrochloric acid (Wako Pure Chemical Industries, Ltd., for volumetric analysis) was passed through the ion exchange resin column to exchange the ion exchange resin into the hydrogen form, and 1 L of ultrapure water was passed through to wash the ion exchange resin. Furthermore, 2 L of 2.38% tetramethylammonium hydroxide solution was passed through the ion exchange resin exchanged into the hydrogen form, and the ion exchange was performed from the hydrogen form to the tetramethylammonium form. After the ion exchange, 1 L of ultrapure water was passed through to wash the ion exchange resin.
Commercially available sodium bromite was added to ultrapure water to obtain a sodium bromite solution. This sodium bromite solution was passed through an ion exchange resin that had been ion-exchanged to a tetramethylammonium type, and the sodium ions were replaced with tetramethylammonium ions to obtain a tetramethylammonium bromite solution.
　超純水、亜臭素酸テトラメチルアンモニウム溶液、オニウム塩、テトラメチルアンモニウムヒドロキシド（２５質量％、トクヤマ社製）、塩酸、上記操作により得られた金属含有液を表１、３に記載の濃度になるように加え混合する事で、実施例１３～１５、３９に記載された組成の残渣除去液を得た。なお、残渣除去液中に含まれる金属は上記ドライエッチング残渣除去液に含まれる金属にて記載した金属であり、残渣除去液中の金属濃度は、残渣除去液中に含有されるＭｇ、Ｃａ、Ｎａ、及びＫの合計含有量から算出される濃度である。 Ultrapure water, tetramethylammonium bromite solution, onium salt, tetramethylammonium hydroxide (25% by mass, Tokuyama Corp.), hydrochloric acid, and the metal-containing liquid obtained by the above procedure were mixed to the concentrations shown in Tables 1 and 3 to obtain residue removal solutions having the compositions shown in Examples 13 to 15 and 39. The metals contained in the residue removal solution are the metals listed in the metals contained in the dry etching residue removal solution above, and the metal concentrations in the residue removal solution are calculated from the total contents of Mg, Ca, Na, and K contained in the residue removal solution.
　超純水へ、市販されている臭素酸ナトリウムを加え、臭素酸ナトリウム溶液を得た。この臭素酸ナトリウム溶液をテトラメチルアンモニウム型にイオン交換したイオン交換樹脂に通液し、ナトリウムイオンをテトラメチルアンモニウムイオンに置換することで臭素酸テトラメチルアンモニウム溶液を得た。
　超純水、臭素酸テトラメチルアンモニウム溶液、オニウム塩、テトラメチルアンモニウムヒドロキシド（２５質量％、トクヤマ社製）、塩酸、上記操作により得られた金属含有液を表１に記載の濃度になるように加え混合する事で、実施例１６～１８に記載された組成の残渣除去液を得た。なお、残渣除去液中に含まれる金属は上記ドライエッチング残渣除去液に含まれる金属にて記載した金属であり、残渣除去液中の金属濃度は、残渣除去液中に含有されるＭｇ、Ｃａ、Ｎａ、及びＫの合計含有量から算出される濃度である。
　超純水へ、市販されている亜塩素酸ナトリウムを加え、亜塩素酸ナトリウム溶液を得た。この亜塩素酸ナトリウム溶液をテトラメチルアンモニウム型にイオン交換したイオン交換樹脂に通液し、ナトリウムイオンをテトラメチルアンモニウムイオンに置換することで亜塩素酸テトラメチルアンモニウム溶液を得た。
　超純水、亜塩素酸テトラメチルアンモニウム溶液、オニウム塩、テトラメチルアンモニウムヒドロキシド（２５質量％、トクヤマ社製）、塩酸、上記操作により得られた金属含有液を表２に記載の濃度になるように加え混合する事で、実施例３７～３９に記載された組成の残渣除去液を得た。なお、残渣除去液中に含まれる金属は上記ドライエッチング残渣除去液に含まれる金属にて記載した金属であり、残渣除去液中の金属濃度は、残渣除去液中に含有されるＭｇ、Ｃａ、Ｎａ、及びＫの合計含有量から算出される濃度である。 Commercially available sodium bromate was added to ultrapure water to obtain a sodium bromate solution, which was then passed through an ion exchange resin that had been ion-exchanged to a tetramethylammonium form, replacing the sodium ions with tetramethylammonium ions to obtain a tetramethylammonium bromate solution.
Ultrapure water, tetramethylammonium bromate solution, onium salt, tetramethylammonium hydroxide (25% by mass, Tokuyama Corp.), hydrochloric acid, and the metal-containing liquid obtained by the above operation were added and mixed to the concentrations shown in Table 1 to obtain residue removing solutions having the compositions shown in Examples 16 to 18. The metals contained in the residue removing solution are the metals shown in the metals contained in the dry etching residue removing solution, and the metal concentrations in the residue removing solution are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solution.
Commercially available sodium chlorite was added to ultrapure water to obtain a sodium chlorite solution. This sodium chlorite solution was passed through an ion exchange resin that had been ion-exchanged to a tetramethylammonium type, and the sodium ions were replaced with tetramethylammonium ions to obtain a tetramethylammonium chlorite solution.
Ultrapure water, tetramethylammonium chlorite solution, onium salt, tetramethylammonium hydroxide (25% by mass, Tokuyama Corp.), hydrochloric acid, and the metal-containing liquid obtained by the above operation were added and mixed to the concentrations shown in Table 2 to obtain residue removing solutions having the compositions shown in Examples 37 to 39. The metals contained in the residue removing solution are the metals shown in the metals contained in the dry etching residue removing solution, and the metal concentrations in the residue removing solution are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solution.
　超純水へ、市販されている塩素酸ナトリウムを加え、塩素酸ナトリウム溶液を得た。この塩素酸ナトリウム溶液をテトラメチルアンモニウム型にイオン交換したイオン交換樹脂に通液し、ナトリウムイオンをテトラメチルアンモニウムイオンに置換することで塩素酸テトラメチルアンモニウム溶液を得た。
　超純水、塩素酸テトラメチルアンモニウム溶液、オニウム塩、テトラメチルアンモニウムヒドロキシド（２５質量％、トクヤマ社製）、塩酸、上記操作により得られた金属含有液を表２、３に記載の濃度になるように加え混合する事で、実施例３３～３５、４３に記載された組成の残渣除去液を得た。なお、残渣除去液中に含まれる金属は上記ドライエッチング残渣除去液に含まれる金属にて記載した金属であり、残渣除去液中の金属濃度は、残渣除去液中に含有されるＭｇ、Ｃａ、Ｎａ、及びＫの合計含有量から算出される濃度である。 Commercially available sodium chlorate was added to ultrapure water to obtain a sodium chlorate solution. This sodium chlorate solution was passed through an ion exchange resin that had been ion-exchanged to a tetramethylammonium type, and the sodium ions were replaced with tetramethylammonium ions to obtain a tetramethylammonium chlorate solution.
Ultrapure water, tetramethylammonium chlorate solution, onium salt, tetramethylammonium hydroxide (25% by mass, Tokuyama Corp.), hydrochloric acid, and the metal-containing liquid obtained by the above operation were added and mixed to the concentrations shown in Tables 2 and 3 to obtain residue removing solutions having the compositions shown in Examples 33 to 35 and 43. The metals contained in the residue removing solutions are the metals shown in the metals contained in the dry etching residue removing solutions, and the metal concentrations in the residue removing solutions are concentrations calculated from the total contents of Mg, Ca, Na, and K contained in the residue removing solutions.
　上記操作により得られた次亜塩素酸テトラメチルアンモニウム溶液に、これと等モルの臭化テトラメチルアンモニウムを加え、次亜臭素酸テトラメチルアンモニウム溶液を得た
。この次亜臭素酸テトラメチルアンモニウム溶液に、上記操作により得られた次亜塩素酸テトラメチルアンモニウム溶液、亜臭素酸テトラメチルアンモニウム溶液、塩素酸テトラメチルアンモニウム溶液、オニウム塩、テトラメチルアンモニウムヒドロキシド（２５質量％、トクヤマ社製）、塩酸、上記操作により得られた金属含有液を表４に記載の濃度になるように加え混合する事で、実施例４４～４６に記載された組成の残渣除去液を得た。なお、残渣除去液中に含まれる金属は上記ドライエッチング残渣除去液に含まれる金属にて記載した金属であり、残渣除去液中の金属濃度は、残渣除去液中に含有されるＭｇ、Ｃａ、Ｎａ、及びＫの合計含有量から算出される濃度である。 The tetramethylammonium hypochlorite solution obtained by the above operation was mixed with equimolar tetramethylammonium bromide to obtain a tetramethylammonium hypobromite solution. The tetramethylammonium hypochlorite solution obtained by the above operation, the tetramethylammonium bromite solution, the tetramethylammonium chlorate solution, the onium salt, the tetramethylammonium hydroxide (25% by mass, manufactured by Tokuyama Corporation), the hydrochloric acid, and the metal-containing solution obtained by the above operation were added to the tetramethylammonium hypobromite solution to the concentrations described in Table 4, and the residue-removing solution having the composition described in Examples 44 to 46 was obtained. The metals contained in the residue-removing solution are the metals described in the metals contained in the dry etching residue-removing solution, and the metal concentration in the residue-removing solution is the concentration calculated from the total content of Mg, Ca, Na, and K contained in the residue-removing solution.
（処理液中の金属量の測定）
　金属量の測定には、トリプル四重極型誘導結合プラズマ質量分析装置（ＩＣＰ-８９００、アジレント・テクノロジー社製）を用いた。Ｍｇ、Ｃａ、Ｎａ、Ｋ、Ｆｅ、Ｃｒ、Ｎｉ、Ｚｎ、Ｃｕ、及びＡｌを含むＩＣＰ分析用元素標準溶液を用いて検量線を作成し、処理液中の金属濃度を測定した。 (Measurement of metal content in treatment solution)
The amount of metal was measured using a triple quadrupole inductively coupled plasma mass spectrometer (ICP-8900, manufactured by Agilent Technologies). A calibration curve was created using standard elemental solutions for ICP analysis containing Mg, Ca, Na, K, Fe, Cr, Ni, Zn, Cu, and Al, and the metal concentration in the treatment solution was measured.
（評価）
　製造した残渣除去液を用いて、上述した方法により、ドライエッチング残渣除去率の評価、ＲｕＯ４ガス発生量、残渣除去液中の酸化剤濃度の安定性、エッチング後の表面平滑性を評価した。
　表１～４に残渣除去液の組成および各評価結果を示す。 (evaluation)
Using the produced residue removing solution, the dry etching residue removal rate, the amount of RuO4 gas generated, the stability of the oxidizing agent concentration in the residue removing solution, and the surface smoothness after etching were evaluated by the methods described above.
Tables 1 to 4 show the compositions of the residue removing solutions and the evaluation results.
（オニウム塩）
Ａ：ベンジルジメチルフェニルアンモニウムイオン
Ｂ：（１－エトキシー１－オキソプロパンー２－イル）トリフェニルホスホニウムイオン
Ｃ：１，１'－（デカン－１，１０－ジイル）ビス[４－アザ－１－アゾニアビシクロ［２．２．２］オクタン］ジイオン
Ｄ：ブチルトリフェニルホスホニウムイオン
Ｅ：（２－カルボキシエチル）トリフェニルホスホニウムイオン
Ｆ：（３－カルボキシプロピル）トリフェニルホスホニウムイオン
Ｇ：（４－カルボキシブチル）トリフェニルホスホニウムイオン
Ｈ：アリルトリフェニルホスホニウムイオン
Ｉ：テトラフェニルホスホニウムイオン
Ｊ：ベンジルトリフェニルホスホニウムイオン (Onium salt)
A: benzyldimethylphenylammonium ion B: (1-ethoxy-1-oxopropan-2-yl)triphenylphosphonium ion C: 1,1'-(decane-1,10-diyl)bis[4-aza-1-azoniabicyclo[2.2.2]octane]diion D: butyltriphenylphosphonium ion E: (2-carboxyethyl)triphenylphosphonium ion F: (3-carboxypropyl)triphenylphosphonium ion G: (4-carboxybutyl)triphenylphosphonium ion H: allyltriphenylphosphonium ion I: tetraphenylphosphonium ion J: benzyltriphenylphosphonium ion
Figure JPOXMLDOC01-appb-T000019
Figure JPOXMLDOC01-appb-T000019
Figure JPOXMLDOC01-appb-T000020
Figure JPOXMLDOC01-appb-T000020
Figure JPOXMLDOC01-appb-T000021
Figure JPOXMLDOC01-appb-T000021
Figure JPOXMLDOC01-appb-T000022
Figure JPOXMLDOC01-appb-T000022

Claims (10)

  1. 　ドライエッチング後の残渣を除去するためのドライエッチング残渣除去液であって
    　次亜臭素酸イオン、臭素酸イオン、亜臭素酸イオン、次亜塩素酸イオン、塩素酸イオン、及び亜塩素酸イオンから成る群から選択される１種以上の酸化剤、Ｍｇ、Ｃａ、Ｎａ、及びＫから成る群から選択される１種以上の金属、並びに、水を含有し、
    　前記残渣除去液のｐＨが、２５℃で９.５以上１４以下であり、前記ドライエッチング残渣除去液において、Ｍｇ、Ｃａ、Ｎａ、及びＫの合計含有量が０．０１ｐｐｔ以上１０００ｐｐｔ以下である、ドライエッチング残渣除去液。     A dry etching residue removal solution for removing residues after dry etching, comprising one or more oxidizing agents selected from the group consisting of hypobromite ions, bromate ions, bromite ions, hypochlorite ions, chlorate ions, and chlorite ions, one or more metals selected from the group consisting of Mg, Ca, Na, and K, and water;
    The dry etching residue removing solution has a pH of 9.5 or more and 14 or less at 25° C., and the total content of Mg, Ca, Na, and K in the dry etching residue removing solution is 0.01 ppt or more and 1000 ppt or less.
  2. 　前記酸化剤の濃度が、０．０００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下である、請求項１に記載のドライエッチング残渣除去液。 The dry etching residue removal solution according to claim 1, wherein the concentration of the oxidizing agent is 0.0001 mol/L or more and 0.40 mol/L or less.
  3. 　前記酸化剤が次亜塩素酸イオンであり、次亜塩素酸イオンの濃度が０．００１ｍｏｌ／Ｌ以上０．４０ｍｏｌ／Ｌ以下である、請求項１に記載のドライエッチング残渣除去液。 The dry etching residue removal solution according to claim 1, wherein the oxidizing agent is hypochlorite ions, and the concentration of the hypochlorite ions is 0.001 mol/L or more and 0.40 mol/L or less.
  4. 　前記酸化剤が次亜臭素酸イオンであり、次亜臭素酸イオンの濃度が０．００１ｍｏｌ／Ｌ以上０．２０ｍｏｌ／Ｌ以下である、請求項２に記載のドライエッチング残渣除去液。 The dry etching residue removal solution according to claim 2, wherein the oxidizing agent is hypobromite ions, and the concentration of the hypobromite ions is 0.001 mol/L or more and 0.20 mol/L or less.
  5. 　さらにオニウムイオンを含み、且つ前記残渣除去液の表面張力が６０ｍＮ／ｍ以上７５ｍＮ／ｍ以下である、請求項１～４のいずれか１項に記載のドライエッチング残渣除去液。 The dry etching residue removal solution according to any one of claims 1 to 4, further comprising onium ions, and the surface tension of the residue removal solution is 60 mN/m or more and 75 mN/m or less.
  6. 　前記オニウムイオンが、式（１）～式（６）で示されるオニウムイオンからなる群から選択される１種以上である、請求項５に記載のドライエッチング残渣除去液。
    Figure JPOXMLDOC01-appb-C000001
    Figure JPOXMLDOC01-appb-C000002
    Figure JPOXMLDOC01-appb-C000003
    Figure JPOXMLDOC01-appb-C000004
    Figure JPOXMLDOC01-appb-C000005
    Figure JPOXMLDOC01-appb-C000006
    （式（１）～式（６）中、
    　Ｒ１、Ｒ２、Ｒ３、Ｒ４、Ｒ５、Ｒ６は独立して、炭素数２～９のアルキル基、アリル基、炭素数１～９のアルキル基を有するアラルキル基、又はアリール基である。また、アラルキル基中のアリール基及びアリール基の環において少なくとも１つの水素は、フッ素、塩素、炭素数１～９のアルキル基、炭素数２～９のアルケニル基、炭素数１～９のアルコキシ基、又は炭素数２～９のアルケニルオキシ基で置き換えられてもよく、これらの基において、少なくとも１つの水素は、フッ素、塩素、臭素、又はヨウ素で置き換えられてもよい。
    　Ａはアンモニウムイオン、又はホスホニウムイオンである。
    　Ｚは、窒素、硫黄、酸素原子を含んでもよい芳香族基又は脂環式基であり、該芳香族基又は該脂環式基において、炭素又は窒素は、塩素、臭素、フッ素、ヨウ素、少なくとも１つの炭素数１～９のアルキル基、少なくとも１つの炭素数２～９のアルケニルオキシ基、少なくとも１つの炭素数１～９のアルキル基で置換されてもよい芳香族基、又は、少なくとも１つの炭素数１～９のアルキル基で置換されてもよい脂環式基を有していてもよい。
    　Ｒは塩素、臭素、フッ素、ヨウ素、炭素数１～９のアルキル基、アリル基、少なくとも１つの炭素数１～９のアルキル基で置換されてもよい芳香族基、又は少なくとも１つの炭素数１～９のアルキル基で置換されてもよい脂環式基である。ｎは１又は２の整数であり、Ｒの数を示す。ｎが２の場合、Ｒは同一又は異なっていてもよく、環を形成してもよい。
    　ａは１～１０の整数である。）     6. The dry etching residue removing solution according to claim 5, wherein the onium ion is at least one type selected from the group consisting of onium ions represented by formulas (1) to (6):
    Figure JPOXMLDOC01-appb-C000001
    Figure JPOXMLDOC01-appb-C000002
    Figure JPOXMLDOC01-appb-C000003
    Figure JPOXMLDOC01-appb-C000004
    Figure JPOXMLDOC01-appb-C000005
    Figure JPOXMLDOC01-appb-C000006
    (In formula (1) to formula (6),
    R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently an alkyl group having 2 to 9 carbon atoms, an allyl group, an aralkyl group having an alkyl group having 1 to 9 carbon atoms, or an aryl group. In addition, at least one hydrogen atom in the aryl group in the aralkyl group and in the ring of the aryl group may be replaced by fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkenyloxy group having 2 to 9 carbon atoms, and in these groups, at least one hydrogen atom may be replaced by fluorine, chlorine, bromine or iodine.
    A is an ammonium ion or a phosphonium ion.
    Z is an aromatic group or an alicyclic group which may contain nitrogen, sulfur or oxygen atoms, and in the aromatic group or the alicyclic group, carbon or nitrogen may have chlorine, bromine, fluorine, iodine, at least one alkyl group having 1 to 9 carbon atoms, at least one alkenyloxy group having 2 to 9 carbon atoms, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms.
    R is chlorine, bromine, fluorine, iodine, an alkyl group having 1 to 9 carbon atoms, an allyl group, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms. n is an integer of 1 or 2 and indicates the number of R. When n is 2, R may be the same or different and may form a ring.
    a is an integer from 1 to 10.
  7. 　前記オニウムイオンの濃度が１質量ｐｐｍ以上１０，０００質量ｐｐｍ以下である、請求項５または６に記載のドライエッチング残渣除去液。 The dry etching residue removal solution according to claim 5 or 6, wherein the concentration of the onium ions is 1 ppm by mass or more and 10,000 ppm by mass or less.
  8. 　請求項１～７のいずれか１項に記載のドライエッチング残渣除去液と半導体ウエハを接触させる工程を含む、半導体ウエハのドライエッチング残渣除去方法。 A method for removing dry etching residues from a semiconductor wafer, comprising a step of contacting the semiconductor wafer with the dry etching residue removal solution according to any one of claims 1 to 7.
  9. 　半導体ウエハをドライエッチングする工程、及び、請求項１～７のいずれか１項に記載のドライエッチング残渣除去液によりドライエッチング残渣を除去する工程を含む、半導体デバイスの製造方法。 A method for manufacturing a semiconductor device, comprising the steps of dry etching a semiconductor wafer and removing dry etching residues using the dry etching residue remover according to any one of claims 1 to 7.
  10. 　前記半導体ウエハがルテニウム系金属を有する半導体ウエハであることを特徴とする、請求項９に記載の半導体デバイスの製造方法。 The method for manufacturing a semiconductor device according to claim 9, characterized in that the semiconductor wafer is a semiconductor wafer having a ruthenium-based metal.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019142788A1 (en) * 2018-01-16 2019-07-25 株式会社トクヤマ Treatment liquid for semiconductor wafers, which contains hypochlorite ions
WO2021060234A1 (en) * 2019-09-27 2021-04-01 株式会社トクヤマ RuO4 GAS GENERATION SUPPRESSION AGENT, AND RuO4 GAS GENERATION SUPPRESSION METHOD
WO2021059666A1 (en) * 2019-09-27 2021-04-01 株式会社トクヤマ Semiconductor treatment liquid for ruthenium and method for producing same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019142788A1 (en) * 2018-01-16 2019-07-25 株式会社トクヤマ Treatment liquid for semiconductor wafers, which contains hypochlorite ions
WO2021060234A1 (en) * 2019-09-27 2021-04-01 株式会社トクヤマ RuO4 GAS GENERATION SUPPRESSION AGENT, AND RuO4 GAS GENERATION SUPPRESSION METHOD
WO2021059666A1 (en) * 2019-09-27 2021-04-01 株式会社トクヤマ Semiconductor treatment liquid for ruthenium and method for producing same

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