WO2010024404A1 - Abrasive composition and method for manufacturing semiconductor integrated circuit device - Google Patents

Abrasive composition and method for manufacturing semiconductor integrated circuit device Download PDF

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Publication number
WO2010024404A1
WO2010024404A1 PCT/JP2009/065103 JP2009065103W WO2010024404A1 WO 2010024404 A1 WO2010024404 A1 WO 2010024404A1 JP 2009065103 W JP2009065103 W JP 2009065103W WO 2010024404 A1 WO2010024404 A1 WO 2010024404A1
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Prior art keywords
polishing
copper
acid
polishing composition
layer
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PCT/JP2009/065103
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French (fr)
Japanese (ja)
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伊織 吉田
広幸 神谷
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旭硝子株式会社
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Priority to JP2010526797A priority Critical patent/JPWO2010024404A1/en
Publication of WO2010024404A1 publication Critical patent/WO2010024404A1/en

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K3/00—Materials not provided for elsewhere
    • C09K3/14—Anti-slip materials; Abrasives
    • C09K3/1454—Abrasive powders, suspensions and pastes for polishing
    • C09K3/1463—Aqueous liquid suspensions
    • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/32115—Planarisation
    • H01L21/3212—Planarisation by chemical mechanical polishing [CMP]

Definitions

  • the present invention relates to a novel polishing composition suitably used for semiconductor integrated circuits and the like.
  • CMP Chemical Mechanical Polishing
  • Specific needs for new polishing compositions include prevention of surface irregularities.
  • Multi-layered wiring means that a circuit is formed and a new circuit is formed using lithography or the like. If the surface of the lower layer circuit has irregularities, the irregularities may also appear on the surface of the layer on which the circuit is newly formed. If this happens, it will be out of the depth of focus in lithography and it will not be possible to form wiring as designed, so in recent semiconductor integrated circuit designs, the surface on which the circuit is formed is planarized with extremely high accuracy, and the surface of the layer above it is formed. It is required not to affect the flatness.
  • an aluminum for forming a wiring groove pattern on the target surface of a semiconductor integrated circuit device and forming the wiring in the groove pattern And a metal having a low specific resistance, such as metal copper.
  • the metal is first formed as a film on the surface by a plating method or a sputtering method.
  • the film is polished by a CMP technique, the metal other than the wiring portion is removed, and a wiring corresponding to the groove is formed. At this time, the polished surface is also flattened.
  • the barrier layer adjacent to the copper layer is exposed.
  • the problem of copper remaining on the barrier layer (copper residue) and the pits (dents) on the copper wiring become problems as surface irregularities.
  • FIG. 1 is a cross-sectional view schematically showing a state in which a portion having a copper residue 21 is raised as compared with a portion 22 having no copper residue. Such a copper residue is likely to occur at a location where the wiring density is high. In that case, the copper wiring at the corresponding location may even be thicker than other locations.
  • FIGS. FIG. 2 shows a state where there is a copper residue 21 at a portion 23 where the wiring density is high.
  • the thickness of the copper wiring in the portion 23 tends to be thicker than the thickness of the copper wiring in the portion 22 where there is no copper remaining.
  • the barrier layer is not shown.
  • the pits on the copper wiring are probably a kind of copper corrosion and are fine enough to be finally seen at a magnification of about tens of thousands of times.
  • Patent Document 1 As a polishing composition for CMP used for polishing copper, an abrasive using rosin (see, for example, Patent Document 1) and a polishing liquid that suppresses erosion by containing a compound having a heterocyclic ring.
  • An invention see, for example, Patent Document 2
  • Patent Document 3 describes that a polishing liquid containing an aliphatic carboxylic acid and benzotriazole is used to adjust the polishing action on copper.
  • these polishing compositions could not completely cope with the copper residue.
  • An object of the present invention is to provide a novel polishing composition that can solve the above-mentioned problem of surface irregularities. Still other objects and advantages of the present invention will become apparent from the following description.
  • the copper layer A polishing composition used in a step of polishing until the adjacent barrier layer is exposed (first polishing step), A dodecylbenzenesulfonic acid component;
  • a polishing composition comprising at least one flatness improver selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component and a polyoxyethylene alkyl ether phosphoric acid component.
  • the polishing composition according to the second aspect wherein the alicyclic resin acid is rosin.
  • the polishing composition according to any one of the above aspects 1 to 4 further comprising colloidal silica as abrasive grains.
  • the polishing composition according to any one of the above aspects 1 to 5, further comprising an oxidizing agent.
  • the polishing composition according to any one of the above aspects 1 to 7, wherein the content of oleic acid in the polishing composition is 0.03% by mass or less.
  • a method of manufacturing a semiconductor integrated circuit device includes an insulating layer having a groove and a copper embedded wiring formed in the groove, A multilayer structure for a semiconductor integrated circuit device in which a barrier layer and a copper wiring layer are formed in this order on the insulating layer, using the polishing composition according to any one of the above aspects 1 to 8, There is provided a method of manufacturing a semiconductor integrated circuit device, comprising polishing until the barrier layer adjacent to a copper layer is exposed.
  • the method for manufacturing a semiconductor integrated circuit device according to the ninth aspect, wherein the barrier layer includes at least one selected from the group consisting of Ta, TaN and TiN.
  • the method for manufacturing a semiconductor integrated circuit device according to the ninth or tenth aspect, wherein the multilayer structure includes a cap layer between the insulating layer and the barrier layer. Is provided.
  • the method for manufacturing a semiconductor integrated circuit device according to any one of the above aspects 9 to 11, wherein the insulating layer having the groove has a relative dielectric constant of 3 or less.
  • the present invention it is possible to solve the problem of dishing while improving the polishing rate of the copper wiring in the first polishing process, and to solve the problem of copper residue and pits on the copper wiring without deteriorating erosion.
  • a novel polishing composition for the polishing process is obtained.
  • FIG. 1 is a cross-sectional view schematically showing a state in which a portion having a copper residue is raised as compared with a portion having no copper residue.
  • FIG. 2 is a cross-sectional view schematically showing a state in which there is a copper residue at a location where the wiring density is high.
  • FIG. 3 is a cross-sectional view schematically showing a state after the cross section in the state of FIG. 2 is subjected to the second polishing step.
  • 4A to 4C are schematic cross-sectional views of the patterned wafer before and after the CMP process in the copper buried wiring forming process.
  • 4A is a cross-sectional view of the semiconductor integrated circuit before polishing, FIG.
  • FIG. 4B is a cross-sectional view of the semiconductor integrated circuit in which dishing has occurred by polishing, and FIG. 4C is ideally polished.
  • FIG. 6 is a cross-sectional view after polishing a semiconductor integrated circuit.
  • FIG. 5 is a schematic cross-sectional view of a patterned wafer for explaining erosion.
  • polishing composition according to the present invention will be described in the case of polishing a surface copper film having a groove for wiring of a semiconductor integrated circuit.
  • the case where the polishing composition according to the present invention is used for polishing copper wiring will be described. It goes without saying that can also be used.
  • the following description exemplifies the present invention, does not limit the scope of the present invention, and it goes without saying that other embodiments may also belong to the category of the present invention as long as they match the gist of the present invention. Yes.
  • the polishing composition according to the present invention is adjacent to the copper layer in pattern formation in which the copper layer provided on the insulating layer via the barrier layer is polished to alternately form the copper embedded wiring and the insulating layer.
  • the polishing composition until the barrier layer is exposed that is, the polishing composition for the first polishing step.
  • the copper portion other than the copper wiring is removed in the first polishing step
  • the barrier layer is removed in the second polishing step, and in most cases, the insulating layer and, if necessary, a part of the copper are extremely used.
  • polishing slightly a flat surface composed of an insulating layer and a copper layer is formed.
  • FIG. 4A A schematic cross section of the patterned wafer before polishing is shown in FIG. 4A.
  • an insulating layer 2 a barrier layer 3, and a wiring metal layer (copper layer) 4 are formed on a Si substrate 1.
  • insulating layer As the insulating layer, a SiO 2 film by plasma CVD using tetraethoxysilane, silane or the like, a low dielectric constant material film (SiOF film, organic SOG film, etc.), and a combination of these with a cap layer, All of these are possible.
  • any known material may be used as the material constituting the insulating layer that is one of the objects to be polished by the polishing composition according to the present invention.
  • An example of such a material is a silicon dioxide film.
  • the silicon dioxide film a film having a crosslinked structure of Si and O and having a ratio of the number of atoms of Si and O of 1: 2 is generally used, but other films may be used.
  • a silicon dioxide film a film deposited by plasma CVD using tetraethoxysilane (TEOS) or silane gas (SiH 4 ) is generally known.
  • TEOS tetraethoxysilane
  • SiH 4 silane gas
  • a film made of a low dielectric constant material having a relative dielectric constant of 3 or less has been used as an insulating layer for the purpose of suppressing signal delay.
  • a low dielectric constant material film include a film made of fluorine-added silicon oxide (SiOF), an organic SOG film (a film containing an organic component obtained by Spin on glass), a low dielectric constant material film such as a porous silica film, An organic silicon material (generally referred to as SiOC) film that is mainly composed of Si—O bonds and includes CH 3 bonds is known. These films can also be suitably used as an insulating layer to which the polishing composition according to the present invention is applied.
  • Organic silicon materials are an extension of conventional technology as process technology, and mass production technology with a wide range of application has been achieved by performing appropriate process tuning. Therefore, a technique for flattening a film using this low dielectric constant material is desired, and the polishing composition according to the present invention can be suitably used.
  • organic silicon material which is a low dielectric constant material
  • trade name: Black Diamond (relative permittivity 2.7, Applied Materials technology), trade name Coral (relative permittivity 2.7, Novellus Systems technology), Aurora 2 7 (relative permittivity 2.7, Japan ASM Co., Ltd. technology) and the like trade name: Black Diamond (relative permittivity 2.7, Applied Materials technology), trade name Coral (relative permittivity 2.7, Novellus Systems technology), Aurora 2 7 (relative permittivity 2.7, Japan ASM Co., Ltd. technology) and the like, and a compound having a Si—CH 3 bond is particularly preferably used.
  • the polishing composition according to the present invention can also be suitably used when a cap layer is formed on an insulating layer.
  • a cap layer is formed on an insulating layer.
  • the cap layer is completely removed and then the insulating layer is shaved and flattened. it can.
  • the cap layer is used to increase the adhesion between the insulating layer and the barrier layer when a low dielectric constant material is used for the insulating layer, or to embed a metal wiring layer in the low dielectric constant insulating layer that is chemically and mechanically fragile. It is a layer provided for the purpose of using as a mask material when the groove is formed by etching or for preventing deterioration of the low dielectric constant material.
  • a film having silicon and oxygen as constituent elements is generally used.
  • An example of such a film is a silicon dioxide film.
  • the silicon dioxide film a film having a crosslinked structure of Si and O and having a ratio of the number of atoms of Si and O of 1: 2 is generally used, but other films may be used.
  • a silicon dioxide film a film deposited by plasma CVD using tetraethoxysilane (TEOS) or silane gas (SiH 4 ) is generally known.
  • the barrier layer is a layer containing at least one selected from the group consisting of Ta, TaN, and TiN formed on the insulating layer by, for example, a sputtering method, and hinders diffusion of copper from the copper layer to the insulating layer. Although arranged for the purpose, in the present invention, in polishing the copper layer, it also serves as a stopper for finding a point in time when the wiring portion appears.
  • the copper layer is formed on the insulating layer via a barrier layer.
  • the film forming method include a method of forming a Cu seed layer to a thickness of about 100 nm by sputtering after forming the barrier layer, and further forming a Cu layer on the Cu seed layer by electrolytic plating.
  • the dishing amount at the time when the barrier layer is exposed is large, the dishing amount varies greatly after the first polishing step is completed and the excess copper layer is removed by overpolishing, and in some cases, the erosion Also occurred.
  • the second polishing step after the barrier layer is shaved, it is necessary to further grind a part of the insulating layer and the copper wiring to finish the copper wiring and the insulating layer smoothly.
  • the amount of polishing in the second polishing step is increased, there may be a portion where the depth of the wiring groove is insufficient due to the in-plane distribution of polishing, or dishing of the copper wiring may be newly generated. Note that erosion is likely to occur in thin wiring portions and dense wiring portions. As shown in FIG.
  • the insulating layer in the wiring portion is excessively polished as compared with the insulating layer portion (Global portion) having no wiring pattern. This is a phenomenon in which the insulating layer is partially thinned. That is, an erosion portion 18 that is further polished than the global portion 20 is generated. In FIG. 5, the barrier layer is omitted.
  • the polishing composition of the present invention when used, the copper wiring is not polished more than necessary by over-polishing, so that the first polishing step does not cause dishing and does not cause erosion. Can be polished.
  • the amount of dishing at the time when the first polishing process is completed by removing the excess copper layer smoothly and uniformly over the entire wafer surface by over-polishing Has a remarkable effect that the thickness can be 55 nm or less.
  • the trench processing amount (wiring groove cutting amount) is shallow, and the polishing amount is reduced. Can be reduced. As a result, the entire process can be performed in a short time, so that the cost can be reduced, and the effects of suppressing variations in the wiring groove depth and dishing of the copper wiring can also be obtained.
  • the polishing composition necessarily contains a dodecylbenzenesulfonic acid component, and at least one selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component and a polyoxyethylene alkyl ether phosphoric acid component.
  • a dodecylbenzenesulfonic acid component at least one selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component and a polyoxyethylene alkyl ether phosphoric acid component.
  • the term “component” is intended to mean that not only the acid itself but also the salt form can be included in addition to the acid itself.
  • the salt form may be generated by reacting with a basic substance added separately as a result of using an acid, or may be added in the form of a salt, but the basic substance added separately as a result of addition as an acid. What is produced by reacting with is common. Specifically, since potassium hydroxide is often used as a basic substance in the polishing composition, at least a part of what is added as an acid reacts with the potassium hydroxide to form a salt. It is thought that.
  • a dodecylbenzenesulfonic acid component is necessarily contained, and at least one flat selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component, and a polyoxyethylene alkyl ether phosphoric acid component.
  • an alkenyl succinic acid component a polyoxyethylene alkyl ether carboxylic acid component
  • a polyoxyethylene alkyl ether phosphoric acid component a dodecylbenzenesulfonic acid component. It has been found that copper residues and pits can be suppressed when included as a property improver. Furthermore, it has been found that the phenomenon called dishing, which scrapes the wiring portion lower than the flat surface, does not deteriorate as compared with conventional abrasives. Furthermore, when the flatness improving agent of the present invention is added, not only the center part (center chip) but also the edge part (edge chip) can be improved. Moreover, the deterioration of erosion is not seen
  • the polishing composition does not contain oleic acid to some extent.
  • the content of oleic acid is 0.03% by mass or less, particularly 0.01%. The mass% or less is preferable.
  • dodecylbenzenesulfonic acid component Specific examples include dodecylbenzenesulfonic acid (see the following formula), sodium dodecylbenzenesulfonate, calcium dodecylbenzenesulfonate, and the like. Note that the carbon chain of the dodecyl group may be linear or branched.
  • dodecylbenzenesulfonic acid has a function as a solubilizing agent for alicyclic resin acids, particularly rosin, and is excellent in that the polishing composition can be concentrated at a high concentration.
  • the content of the dodecylbenzenesulfonic acid component in the polishing composition is 0.002 to 0.2% by mass, further 0.005 to 0.15% by mass, and 0.005 to 0.1% by mass. It is preferable because the polishing composition can be concentrated efficiently.
  • alkenyl succinic acid component examples include alkenyl succinic acid, alkenyl succinic acid dipotassium salt, alkenyl succinic acid dipotassium, alkenyl succinic anhydride and the like.
  • this alkenyl succinic acid dishing can be effectively prevented, and it is excellent in that the effect is seen in a small amount.
  • Flatness is greatly improved by using an alkenyl succinic acid component and an alicyclic resin acid, particularly rosin. The reason is not exactly known, but it is assumed that the alkenyl succinic acid component and the alicyclic resin acid have some chemical synergistic effect.
  • the content of the alkenyl succinic acid component in the polishing composition is 0.0005 to 0.01% by mass, more preferably 0.0007 to 0.008% by mass, and 0.0007 to 0.006% by mass. However, it is preferable because dishing can be effectively prevented.
  • the content ratio (mass ratio) of the alkenyl succinic acid component and the alicyclic resin acid is 1:80 to 1: 5, particularly 1:60 to 1: 3, while preventing dishing. It is preferable because copper residue and pits can be improved.
  • polyoxyethylene alkyl ether carboxylic acid component examples include polyoxyethylene (3) tridecyl ether acetic acid, polyoxyethylene (7) tridecyl ether acetic acid, polyoxyethylene (6) tridecyl ether acetic acid, poly Oxyethylene (3) tridecyl ether sodium acetate, polyoxyethylene (7) sodium tridecyl ether acetate, polyoxyethylene (6) sodium tridecyl ether acetate, polyoxyethylene (4.5) lauryl ether acetic acid and polyoxyethylene (10) Lauryl ether acetic acid and the like are exemplified.
  • polyoxyethylene alkyl ether carboxylic acid component By using a polyoxyethylene alkyl ether carboxylic acid component and an alicyclic resin acid, particularly rosin, flatness is greatly improved. Although the reason is not exactly known, it is assumed that the polyoxyethylene alkyl ether carboxylic acid component and the alicyclic resin acid have some chemical synergistic effect.
  • the polyoxyethylene alkyl ether carboxylic acid component is preferable in that the temperature dependency of the concentration is small and the polishing performance for copper is excellent. Moreover, it is preferable at the point which can be further concentrated by including both a dodecylbenzenesulfonic acid component and a polyoxyethylene alkyl ether carboxylic acid component.
  • polyoxyethylene (3) tridecyl ether acetic acid means a substance consisting of a polyoxyethylene moiety consisting of three oxyethylene bonds and tridecyl ether acetic acid.
  • polyoxyethylene (n) alkyl ether carboxylic acids can be represented as RO- (C 2 H 2 O) n —CH 2 COOH.
  • R is an alkyl group composed of 10 to 15 carbons, and may be linear or branched.
  • the content of the polyoxyethylene alkyl ether carboxylic acid component in the polishing composition is 0.005 to 0.1% by mass, more preferably 0.01 to 0.07% by mass. It is preferable because dishing can be prevented. Further, the content ratio (mass ratio) of the polyoxyethylene alkyl ether carboxylic acid component and the alicyclic resin acid is 2: 1 to 1: 5, particularly 1: 1 to 1: 3. It is preferable because the copper residue can be improved while preventing.
  • the ratio of the polyoxyethylene alkyl ether carboxylic acid component to dodecylbenzene sulfonic acid is preferably 5: 1 to 1: 5, and more preferably 3: 1 to 1: 3.
  • polyoxyethylene alkyl ether phosphate component examples include polyoxyethylene (10) lauryl ether phosphate, dipolyoxyethylene (10) lauryl ether phosphate, polyoxyethylene (8) oleyl ether phosphate, Dipolyoxyethylene (8) oleyl ether phosphoric acid, polyoxyethylene (2) (C 12-15 ) alkyl ether phosphoric acid, polyoxyethylene (4) (C 12-15 ) alkyl ether phosphoric acid, polyoxyethylene ( 8) (C 12-15 ) alkyl ether phosphoric acid, polyoxyethylene (10) (C 12-15 ) alkyl ether phosphoric acid, tripolyoxyethylene (4) lauryl ether phosphoric acid, polyoxyethylene (1) lauryl ether phosphor Examples are acids and their salts.
  • polyoxyethylene (8) oleyl ether phosphoric acid means that it consists of a polyoxyethylene moiety consisting of eight oxyethylene bonds and an oleyl ether phosphate moiety.
  • polyoxyethylene (n) lauryl ether phosphoric acid can be represented as C 12 H 25 O— (C 2 H 2 O) n —H 2 PO 4 .
  • (C 12-15 ) represents the structure of an alkyl group, specifically an alkyl group having 12 to 15 carbon atoms.
  • the content of the polyoxyethylene alkyl ether phosphoric acid component in the polishing composition is 0.005 to 0.1% by mass, more preferably 0.01 to 0.05% by mass. Can be prevented. Further, the content ratio (mass ratio) of the polyoxyethylene alkyl ether phosphoric acid component and the alicyclic resin acid is 2: 1 to 1: 5, particularly 1: 1 to 1: 3. It is preferable because the copper residue can be improved while preventing.
  • the alkenyl succinic acid component, polyoxyethylene alkyl ether carboxylic acid component and polyoxyethylene alkyl ether phosphoric acid component may all be contained, or only one component may be contained. Since the alkenyl succinic acid component has the same effect in a very small amount as compared with other components, the viscosity of the polishing composition can be prevented from rising more than necessary.
  • the polyoxyethylene alkyl ether carboxylic acid component is most excellent in terms of maintaining a good polishing rate and in terms of polishing stability.
  • the alkenyl succinic acid component, the polyoxyethylene alkyl ether carboxylic acid component and the polyoxyethylene alkyl ether phosphoric acid component can all contribute to the flattening of the polished surface, and are therefore referred to as flatness improvers.
  • This polishing composition is preferable in terms of low viscosity. Viscosity is a more important factor than expected in technical fields such as CMP. This is because it is generally very important to make the polishing conditions constant in order to perform stable polishing. However, when the viscosity of the polishing composition is too high, clogging may occur in the abrasive conveyance system or the abrasive may remain. Therefore, whether or not polishing can be performed under the same conditions during long-term polishing largely depends on the viscosity of the abrasive. In order to improve the viscosity, it is preferable not to contain a water-soluble polymer.
  • the water-soluble polymer is a water-soluble polymer having a molecular weight of 5000 or more.
  • the polishing composition may contain a complex forming agent.
  • the complex forming agent means a substance that forms a complex with copper. Inclusion of the complexing agent increases the copper polishing rate, although the mechanism is not clear. Specifically, it is as follows.
  • Carboxylic acid having a nitrogen-containing heterocyclic group (monocarboxylic acid, polycarboxylic acid): 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, 2,3-pyridinedicarboxylic acid, 2,4-pyridine Dicarboxylic acid, 2,5-pyridinedicarboxylic acid, 2,6-pyridinedicarboxylic acid, 3,4-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, pyrazinecarboxylic acid, 2,3-pyrazinedicarboxylic acid, 2-quinoline Carboxylic acid (quinaldic acid), 3-quinoline carboxylic acid, 4-quinoline carboxylic acid, 8-quinoline carboxylic acid.
  • Carboxylic acid having amino group (amino acid etc.): alanine, glycine, proline, phenylalanine.
  • Carboxylic acid having a hydroxyl group (such as hydroxycarboxylic acid): lactic acid, malic acid, citric acid, isocitric acid, tartaric acid, glycolic acid, gluconic acid, salicylic acid.
  • Carboxylic acid having a thiol group thioglycolic acid, thiosalicylic acid.
  • the complex-forming agent is preferably a polycarboxylic acid or monocarboxylic acid having a nitrogen-containing heterocyclic group, or an aliphatic polycarboxylic acid such as oxalic acid, particularly 2-pyridinecarboxylic acid or 2,3-pyridinecarboxylic acid. Is preferred.
  • a carboxylic acid having a nitrogen-containing heterocyclic group such as 2-pyridinecarboxylic acid, the polishing rate of copper is particularly increased, and adhesion and residue of a copper complex or the like on the polishing pad can be prevented. Demonstrated.
  • the content of the complex-forming agent in the polishing composition of the present invention is 0.1 to 5% by mass, particularly 0.3 to 3% by mass, more preferably 0.5 to 1.5% by mass with respect to the polishing composition. It is preferable that it is mass%. If the amount is less than 0.1% by mass, the polishing rate of copper may decrease, and if it exceeds 5% by mass, corrosion or dishing of the copper surface may occur.
  • the polishing composition preferably contains an alicyclic resin acid.
  • Resin acid is an organic acid (carboxylic acid) that is present as a free or ester in natural resin
  • alicyclic resin acid is a compound having an alicyclic structure among the resin acids (published by Kyoritsu Shuppan Co., Ltd.) (See “Resin acid” in Chemical Dictionary 4).
  • alicyclic resin acid in the present invention a natural resin containing an alicyclic resin acid, a refined product mainly composed of an alicyclic resin acid purified from a natural resin (at the same time, isomerization or the like may occur). Examples thereof include resin acids, alicyclic resin acids which are single compounds extracted from natural resins, and mixtures of two or more thereof.
  • the purified resin acid examples include rosin obtained from pine resin, tall oil, tall oil rosin and the like.
  • a purified resin acid mainly composed of an alicyclic resin acid such as rosin, abietic acid or its isomer, pimaric acid or its isomer, or hydrogenated abietic acid is preferable.
  • a commercially available rosin can be used.
  • rosin is a compound whose composition ratio varies depending on the type of natural resin from which it is derived, but any type of rosin can be used as long as it has an alicyclic resin acid as a main component. Can be used.
  • rosins contain a small amount of aliphatic resin acid.
  • the aliphatic resin acid is mainly an unsaturated higher fatty acid such as oleic acid or linoleic acid, and its content is usually about 10% by mass relative to the whole rosin.
  • alicyclic resin acids that are single compounds include abietic acid, isomers of abietic acid, neoabietic acid, parastrinic acid, levopimaric acid, and the like.
  • dehydroabietic acid and secodehydroabietic acid which are dehydrogenated products of acids.
  • two or more alicyclic resin acids may be contained.
  • a purified resin acid such as rosin is originally a mixture of two or more alicyclic resin acids (single compound), but is regarded as one alicyclic resin acid in the present invention. Therefore, in the polishing composition, two or more kinds of rosins may be contained, or one or more kinds of alicyclic resin acids which are a single compound with rosin may be contained.
  • the alicyclic resin acid may be a derivative of the above-described purified resin acid or a single compound alicyclic resin acid, which is a compound having at least one carboxy group or a mixture containing the same. Good.
  • the derivatives include isomerized products, hydrides, dehydrogenated products, multimerized products, unsaturated compounds (eg, maleic anhydride, alicyclic resin acids) other than alicyclic resin acids extracted from natural resins.
  • unsaturated compounds eg, maleic anhydride, alicyclic resin acids
  • Maleic anhydride adduct maleic acid modified product
  • fumaric acid adduct fumaric acid-modified product
  • at least one selected from the group consisting of dehydrogenated products are preferable, and the dehydrogenated product includes those in which a part of the alicyclic ring is converted to an aromatic ring by dehydrogenation.
  • the content of abietic acid (including neoabietic acid which is an isomer of abietic acid, dihydroabietic acid which is a hydride of abietic acid, tetrahydroabietic acid, dehydrogenated product of abietic acid, etc.) is 0.5 to The content of 2.5% by mass, and further 0.15 to 1.5% by mass is preferable because the copper surface can be effectively protected.
  • the content ratio (mass ratio) of dodecylbenzenesulfonic acid and alicyclic resin acid is 4: 1 to 1: 4, particularly 3: 1 to 1 in that the polishing composition can be concentrated effectively. : 3 is preferable.
  • Alicyclic resin acids include salts of alicyclic resin acids.
  • alicyclic resin acid salt rosin alkali metal salt (particularly potassium salt), rosin ammonium salt, and rosin organic amine salt, also called rosin, are preferable.
  • rosin alkali metal salt particularly potassium salt
  • rosin ammonium salt rosin ammonium salt
  • rosin organic amine salt also called rosin
  • salts for example, these 2 or more types of mixtures can also be used.
  • an effect of suppressing the amount of dishing can be obtained by including an alicyclic fatty acid.
  • the mechanism for obtaining such an effect acts as a surface protective agent that forms a protective layer on the surface of the copper film by performing some chemical or physical action on the surface of the semiconductor integrated circuit copper film during polishing. It is thought that.
  • This surface protective layer is not so strong as to completely hinder the polishing of the copper film, and in the copper film on the semiconductor integrated circuit substrate, the polishing progresses at the convex portion where the pressing pressure of the polishing pad is large, and the pressing pressure is small. Polishing does not proceed in the concave portion of the wiring portion. Thereby, it is considered that a highly smooth polished surface property is realized.
  • the content of the alicyclic resin acid in the polishing composition is 0.1 to 5% by mass, further 0.3 to 3% by mass, 0.3% to 2% by mass, 0.3% to 1% by mass. It is preferable that it is mass%. If it is less than 0.01% by mass, it is considered that the protective action of the copper film surface is insufficient, and corrosion and dishing are likely to occur during polishing. On the other hand, if it exceeds 2% by mass, the polishing rate of copper may decrease.
  • the content ratio (mass ratio) of the complex-forming agent and the alicyclic resin acid is 50: 1 to 30: 1, particularly 45: 1 to 35: 1 in that the polishing rate can be improved. preferable.
  • the mechanism of the oxidizing agent plays a role of oxidizing a metal such as copper to form a metal ion or oxide. It is considered that the polishing proceeds when the copper ions generated by the reaction with the oxidizing agent and the complex forming agent form a complex.
  • a peroxide having an oxygen-oxygen bond that generates a radical by dissociation of an oxygen-oxygen bond by external energy such as heat or light is preferable because it exhibits a strong oxidizing power.
  • peroxide-based oxidizing agents include inorganic peroxides such as hydrogen peroxide, persulfates, peroxocarbonates, peroxosulfates, peroxophosphates, benzoyl peroxide, t-butylhydro Examples thereof include organic peroxides such as peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, performic acid and peracetic acid.
  • Preferred oxidizing agents are hydrogen peroxide, ammonium persulfate, or potassium persulfate.
  • these oxidizing agents it is more preferable to use ammonium salts, particularly ammonium persulfate, because a high polishing rate can be obtained for the copper film.
  • the preferred oxidizing agents are then hydrogen peroxide and potassium persulfate.
  • the content of the oxidizing agent in the polishing composition is preferably 0.1 to 5% by mass, particularly 0.5 to 3% by mass, and 0.5 to 1.5% by mass. If it is less than 0.1% by mass, the copper polishing rate may decrease. If it exceeds 5% by mass, corrosion or dishing of the copper surface tends to occur.
  • at least one oxidizing agent selected from ammonium persulfate, hydrogen peroxide, and potassium persulfate In particular, it is preferable to use ammonium persulfate.
  • the main liquid medium in the polishing composition of the present invention is water, and preferably consists of water alone or a mixture of water and a water-soluble solvent.
  • water it is preferable to use pure water which has been subjected to ion exchange and from which foreign substances have been removed.
  • water-soluble solvent water-soluble alcohols, water-soluble polyols, water-soluble esters, water-soluble ethers, and the like can be used.
  • the liquid medium in the polishing composition of the present invention is preferably water alone or a mixed solvent of water containing 80% by mass or more of water and a water-soluble organic solvent, and most preferably consists essentially of water.
  • the proportion of the liquid medium in the polishing composition of the present invention is preferably 90% by mass or more, particularly 95% by mass or more.
  • Substantially the total amount of the liquid medium is preferably composed of water.
  • the water content in the polishing composition of the present invention is preferably 90% by mass or more, particularly preferably 95% by mass or more.
  • the ratio of each component of the polishing composition of the present invention refers to the composition ratio when polishing is performed.
  • the polishing composition is diluted prior to polishing and the diluted solution is used for polishing, the ratio of each component described above and below is a ratio in the diluted product.
  • the polishing composition is usually diluted with a liquid medium (especially water), and in this case, the relative proportions of the components other than the liquid medium are usually not changed before and after the dilution.
  • the pH value of the polishing composition of the present invention is preferably 7.5 to 12, particularly 8 to 11, and more preferably 8.5 to 10.5. More preferably, it is 9-10.
  • the pH value is preferably 8.0 or more.
  • a pH value higher than 12 is not preferable because corrosion of the copper film is remarkable.
  • the pH value is preferably 11 or less.
  • a pH adjuster can be used.
  • potassium hydroxide, organic amine, or ammonia any of these may be used, but it is preferable to use an organic amine or ammonia that forms a complex ion with copper because a large polishing rate can be obtained with respect to the copper film.
  • the pH may be adjusted to a desired pH value by adjusting the pH to the acidic side by adding nitric acid, sulfuric acid, phosphoric acid, etc. once the basic pH is set to the desired pH value.
  • the order of the step of mixing the pH adjuster is not limited.
  • a liquid medium is used.
  • a liquid medium made basic by mixing with a pH adjuster (some or all of other components may already be contained) is prepared, dissolution and mixing of the alicyclic resin acid and the like are facilitated. It is preferable because it becomes difficult to separate.
  • the polishing composition of the present invention can exert its effect even when no abrasive grains are blended.
  • the abrasive composition may be blended and used, and in that case, copper can be further polished at a high speed.
  • Examples of abrasive grains that can be blended in the polishing composition of the present invention include ⁇ -alumina, ⁇ -alumina, ⁇ -alumina, silica, and ceria. However, among these, it is preferable to use silica. When silica is used, colloidal silica is more preferably used from the viewpoints of dispersibility, stability, polishing power, and the like.
  • the average secondary particle diameter is preferably 10 to 200 nm. If the average secondary particle diameter exceeds 200 nm, it is difficult to increase the concentration of the abrasive grains because the abrasive particle diameter is too large, and if it is less than 10 nm, it is difficult to improve the polishing rate.
  • the range of 20 to 120 nm is preferable.
  • the content of the abrasive grains in the polishing composition of the present invention is 0.01 to 10% by mass, particularly 0.05 to 5% by mass, further 0.05 to 2% by mass, 0.05 to 1% by mass, 0%. 0.05 to 0.6% by mass is preferable.
  • the polishing composition preferably contains a rust inhibitor.
  • the rust inhibitor is preferably an imidazole derivative, particularly in terms of preventing pits.
  • the imidazole derivative specifically refers to imidazole and benzene in which 1 to 5 positions shown in the following formula may be substituted with a methyl group, and the 4 and 5 positions may be benzene which may have a substituent.
  • the imidazole derivative examples include benzimidazole, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, and the like. These may be used alone or in combination of two or more.
  • the imidazole derivative is preferably contained in an amount of 0.001 to 0.5%, more preferably 0.003 to 0.3% based on the total mass of the polishing composition in terms of polishing characteristics.
  • a reducing agent, a viscosity modifier, a dispersing agent, a preservative, and the like can be appropriately blended in addition to the above-described components as long as the gist of the present invention is not violated.
  • these contents are generally 10% by mass or less, and particularly preferably 5% by mass or less and 3% by mass or less in total.
  • the polishing composition thus configured can suppress copper residue and pits when copper is used as a wiring metal, and can realize highly accurate surface flattening. Therefore, it is possible to obtain a semiconductor integrated circuit surface having an excellent flat surface state, which is extremely effective for multilayering and thinning of the semiconductor integrated circuit.
  • the polishing composition according to the present invention is suitable for polishing a copper film formed on a surface having a groove for wiring as an abrasive.
  • Other constituent components may be added to the polishing composition according to the present invention and used as an abrasive. More specifically, since the progress of dishing and erosion is effectively suppressed in the method of manufacturing a semiconductor integrated circuit device in which copper wiring is formed by the damascene method, a semiconductor integrated circuit surface having an excellent flat surface state is obtained. be able to.
  • the polishing composition according to the present invention essentially contains a dodecylbenzenesulfonic acid component, and is at least one selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component, and a polyoxyethylene alkyl ether phosphoric acid component. Contains two flatness improvers. In the pattern formation in which the copper layer provided on the insulating layer through the barrier layer is polished by the above composition to form the copper embedded wiring having a width of 100 ⁇ m and the insulating layer having a width of 100 ⁇ m alternately.
  • the amount of dishing when the copper is polished for 200 nm at the polishing rate of copper before the barrier layer is exposed Is 55 nm or less, particularly 45 nm or less.
  • Polishing conditions include variable conditions such as polishing speed and pressing pressure of the polishing pad, but there are no particular restrictions on these conditions.
  • the polishing rate is preferably 200 to 800 nm / min, and the pressing pressure of the polishing pad is preferably 4 psi (converted value is 27.6 kPa) or less.
  • the dishing amount is a depth represented by reference numeral 7 in FIG. 4B (or a depth represented by reference numeral 17 in FIG. 5), as will be described later.
  • the polishing composition according to the present invention is a polishing method for pattern formation in which a copper layer provided on an insulating layer via a barrier layer is polished to alternately form copper embedded wiring and insulating layers.
  • the second polishing step of polishing with the second polishing composition can be preferably used.
  • the present polishing method that selectively uses these two types of polishing compositions can realize an excellent flat surface with less dishing and erosion and good in-plane uniformity when copper is used as a wiring metal. For this reason, it is extremely effective for multilayering and thinning of semiconductor integrated circuits.
  • first polishing step and the second polishing step it is generally preferable to perform the second polishing step immediately after the first polishing step to complete the polishing, but the first polishing step and the second polishing step are performed as necessary.
  • other steps may be included before the first polishing step or after the second polishing step.
  • end time of the first polishing step and the start time and end time of the second polishing step which can be appropriately determined according to the actual situation of polishing, but usually, a barrier layer is interposed on the insulating layer.
  • the first polishing process is stopped and the process proceeds to the second polishing process, and when the predetermined surface flatness is obtained, the second polishing process is stopped. That is, the copper portion other than the copper wiring is removed in the first polishing step, the barrier layer is removed in the second polishing step, and in most cases, the insulating layer and, if necessary, a part of the copper are extremely used. By polishing slightly, a flat surface composed of an insulating layer and a copper layer is formed.
  • Examples 1 to 64 and 86 to 111 are examples, and examples 65 to 85 are comparative examples.
  • compositions of the polishing compositions in Examples 1 to 111 are as summarized in Tables 1 to 6. Content of each component was described by the mass% with respect to the whole polishing composition mixed. The pH value was measured with a pH meter pH81-11 manufactured by Yokogawa Electric Corporation. The average secondary particle size of colloidal silica was measured by a dynamic light scattering method using a Microtrac UPA-ST150 particle size analyzer manufactured by NIKKISO. The measurement sample was measured by diluting with pure water in an appropriate concentration range determined by the apparatus, which can obtain appropriate scattering and reflected light intensity for measurement.
  • the polishing composition for Example 1 was prepared by adding a predetermined amount of 2-pyridinecarboxylic acid, which is a complex-forming agent, to ion-exchanged water, and then adjusting the pH so that the pH was as described in Table 2. Potassium hydroxide as a regulator was added and stirred thoroughly. Further, with stirring, KR614 (produced by Arakawa Chemical Industries) as an alicyclic resin acid, dodecylbenzenesulfonic acid as a dissolution aid, alkenyl succinic acid as a flatness improving agent, and APS (ammonium persulfate) as an oxidizing agent. Then, colloidal silica as an abrasive was added to prepare. Other examples other than Example 1 were processed in the same manner as in Example 1 with the compositions as shown in Tables 1 to 6 to obtain polishing compositions.
  • 2-pyridinecarboxylic acid which is a complex-forming agent
  • PTAH Phenyl Trimethyl Ammonium Hydroxide 0.2 M methanol solution, manufactured by GL Sciences Inc.
  • the measurement was carried out after methyl esterification.
  • the column used was a capillary column packed with DEGS (Diethylene glycol succinate) with an inner diameter of 0.25 mm, a length of 25 m, and a film thickness of 0.25 ⁇ m.
  • the oven temperature was 180 ° C. and the sample injection amount was 4.0 ⁇ l. .
  • polishing characteristics of the polishing composition were evaluated by the following methods.
  • a blanket wafer and a patterned wafer were used as the objects to be polished.
  • an 8-inch wafer (000 CUR015 manufactured by Sematech Co., Ltd.) in which a 1500 nm thick copper film was formed on the Si substrate by wet plating was used for copper polishing rate evaluation.
  • An 8-inch wafer (trade name: 854CMP225) manufactured by Sematech was used as the wafer with a pattern.
  • a schematic cross section of the patterned wafer before polishing is shown in FIG.
  • This patterned wafer is a 25-nm-thick tantalum film formed by sputtering on an insulating layer 2 made of SiO 2 in which concave and convex portions in which embedded wirings formed on the Si substrate 1 are embedded are formed.
  • a wiring metal layer 4 made of a copper film having a predetermined film thickness formed by wet plating, and a wiring pattern having a wiring width of 100 ⁇ m to 180 nm. Is formed.
  • the film thickness of the copper film on the surface of the barrier layer 3 made of the tantalum film on the convex portion of the insulating layer 2 is the initial film thickness 8, and the copper film formed on the convex portion and the concave portion of the insulating layer 2
  • the step is the initial step 9.
  • the initial film thickness was 900 nm and the initial step was 350 nm.
  • polishing machine a fully automatic CMP apparatus MIRRA manufactured by APPLIED MATERIALS was used.
  • a polishing pad XYK-groove (manufactured by Nitta Haas) having a two-layer pad IC1400 was used, and conditioning was performed using MEC100-PH3.5L (manufactured by Mitsubishi Materials Corporation).
  • the polishing composition of Example 1 was supplied at a rate of 200 ml / min, the rotation speed of the polishing head (Head) and the polishing platen (Platen) was 123 rpm and 117 rpm, respectively, and the polishing pressure was Performed at 2 psi or 13.8 kPa.
  • the supply rate of the polishing composition was 200 ml / min, and the rotation speeds of the polishing head (Head) and the polishing platen (Platen) were 123 rpm and 117 rpm, respectively.
  • the polishing pressure is 1.5 psi for Examples 4 to 30, 33, 34, 47 to 49, 57 to 63, 90, 94, 95, 98 to 100, 102 to 109, or 10.4 kPa. Performed at 2 psi or 13.8 kPa.
  • the copper polishing rate using a blanket wafer was measured using a film thickness meter RS-75 (manufactured by KLA-Tencor). That is, for the copper blanket wafer, the film thickness before polishing and the film thickness after polishing for 1 minute were measured, and the copper polishing rate (nm / min) was obtained from the difference.
  • the polishing rate of Cu is preferably 700 nm or more.
  • Polishing of the wafer with a pattern used for polishing the polishing composition was performed while monitoring the polishing end point by an optical polishing end point detection method. That is, as the polishing progresses, the barrier layer made of tantalum begins to be exposed, and after the polishing is finished until the polishing end point at which the decrease in reflectivity almost stops and becomes constant, overpolishing is further performed for 30 seconds. At the polishing end point, a part of the copper film on the barrier layer was removed, and the excess copper film remaining in part was removed by overpolishing.
  • the polishing end point is the polishing time up to the point of time when the “barrier layer is exposed by removing a part of the copper film on the barrier layer” in the above-mentioned, and the over-polishing time is the subsequent polishing time.
  • Polishing time The total polishing time is the sum of the polishing end point and the over polishing time.
  • the dishing measurement was performed separately for the center chip and the edge chip.
  • the center chip is the chip at the center of the 20 mm square chips existing on the wafer, and the edge chip is the chip closest to the end of the 20 mm square chips present on the wafer. It is.
  • Each value of the center chip and the edge chip is preferably 50 nm or less, particularly preferably 30 nm or less.
  • the difference in dishing amount between the center chip and the edge chip is preferably 20 nm or less, particularly preferably 10 nm or less.
  • FIG. 4B Schematic cross-sectional view of the patterned wafer after polishing is shown in FIG.
  • the wiring metal layer 4 made of a copper film is completely polished, and the surface of the barrier layer 3 made of a tantalum film is exposed.
  • the surface of the barrier layer 3 on the convex portion of the insulating layer 2 is polished by the depth indicated by reference numeral 7.
  • the height of the surface step was defined as a dishing amount of 7.
  • FIG. 4C is a schematic cross-sectional view of an ideally polished patterned wafer, in which embedded wiring is formed without causing such a surface step.
  • Example 2 and Example 43 contain a specific flatness improver, so that it can be seen that dishing is greatly improved without deteriorating copper residue and pits.
  • Examples 82 to 84 it can be seen that although benzimidazole is contained, oleic acid is contained, and the copper residue and pits are deteriorated.
  • the present invention it is possible to solve the problem of dishing while improving the polishing rate of the copper wiring in the first polishing process, and to solve the problem of copper residue and pits on the copper wiring without deteriorating erosion.
  • a novel polishing composition for the polishing process is obtained.

Abstract

An abrasive composition which is used during the pattern formation wherein buried copper wiring and insulating layers are alternately formed by grinding each copper layer formed on each insulating layer via a barrier layer, specifically in a process wherein each copper layer is ground until the barrier layer adjacent thereto is exposed.  The abrasive composition contains a dodecylbenzenesulfonic acid component, and at least one planarity-improving agent selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component and a polyoxyethylene alkyl ether phosphoric acid component.

Description

研磨用組成物および半導体集積回路装置の製造方法Polishing composition and method for manufacturing semiconductor integrated circuit device
　本発明は、半導体集積回路などに好適に用いられる新規な研磨用組成物に関する。 The present invention relates to a novel polishing composition suitably used for semiconductor integrated circuits and the like.
　近年、半導体集積回路の高集積化へのニーズの高まりに呼応して、半導体素子の細線化、配線の多層化等、種々の微細加工技術が開発されている。このため、配線形成に関わるＣｈｅｍｉｃａｌ　Ｍｅｃｈａｎｉｃａｌ　Ｐｏｌｉｓｈｉｎｇ（以下、ＣＭＰという）では、新規な研磨用組成物に対するニーズが大きい。なお、ＣＭＰ用の研磨用組成物は、単なる機械的な研磨用組成物と比較して、非常に精度の高い研磨を要求されるため、非常に緻密な調整が必要となる。 In recent years, various fine processing techniques such as thinning of semiconductor elements and multilayering of wiring have been developed in response to the increasing needs for higher integration of semiconductor integrated circuits. For this reason, in Chemical Mechanical Polishing (hereinafter referred to as CMP) related to wiring formation, there is a great need for a new polishing composition. In addition, since the polishing composition for CMP is required to be polished with a very high accuracy as compared with a mere mechanical polishing composition, very fine adjustment is required.
　新規な研磨用組成物に対する具体的なニーズとしては、表面の凹凸防止がある。 Specific needs for new polishing compositions include prevention of surface irregularities.
　配線の多層化とは、回路を形成した上にリソグラフィー等を用いて新たな回路を形成するものである。下層となる回路の表面に凹凸があると、その上にある、新たに回路を形成する層の表面にも凹凸が現れる可能性がある。そうなると、リソグラフィーにおける焦点深度から外れ、設計どおりの配線が形成できなくなることから、近年の半導体集積回路の設計においては、回路を形成した表面を極めて高い精度で平坦化し、その上の層の表面の平坦性に影響を与えないようにすることが要求されている。 “Multi-layered wiring” means that a circuit is formed and a new circuit is formed using lithography or the like. If the surface of the lower layer circuit has irregularities, the irregularities may also appear on the surface of the layer on which the circuit is newly formed. If this happens, it will be out of the depth of focus in lithography and it will not be possible to form wiring as designed, so in recent semiconductor integrated circuit designs, the surface on which the circuit is formed is planarized with extremely high accuracy, and the surface of the layer above it is formed. It is required not to affect the flatness.
　また、品質の面でも、表面の凹凸は配線の電気特性に影響を与えるため、品質上のばらつきを抑えるためにできるだけ抑制すべきである。 Also, in terms of quality, unevenness on the surface affects the electrical characteristics of the wiring, so it should be suppressed as much as possible in order to suppress variations in quality.
　たとえば、回路形成表面の平坦化の際に同時に回路の配線を形成するダマシン法では、半導体集積回路装置の対象表面に配線用の溝パターンを形成し、その溝パターンに配線を形成するためのアルミニウムや金属銅等の比抵抗の低い金属を埋め込むように形成する。金属は、まず、メッキ法やスパッタリング法により表面上に膜として形成され、多くの場合、その膜をＣＭＰ技術によって研磨し、配線部以外の金属を除去し、溝に対応した配線を形成する。この際に、あわせて研磨面の平坦化がおこなわれる。 For example, in a damascene method in which circuit wiring is simultaneously formed when a circuit forming surface is flattened, an aluminum for forming a wiring groove pattern on the target surface of a semiconductor integrated circuit device and forming the wiring in the groove pattern And a metal having a low specific resistance, such as metal copper. The metal is first formed as a film on the surface by a plating method or a sputtering method. In many cases, the film is polished by a CMP technique, the metal other than the wiring portion is removed, and a wiring corresponding to the groove is formed. At this time, the polished surface is also flattened.
　この場合、絶縁層上にバリア層を介して設けられた銅層を研磨して、銅埋め込み配線と絶縁層とを交互に形成するパターン形成において、銅層に隣接したバリア層が露出するまでの段階（いわゆる第１研磨工程）では、バリア層上に銅が残る問題（銅残り）や銅配線上のピット（くぼみ）が表面の凹凸として問題になる。 In this case, in the pattern formation in which the copper layer provided on the insulating layer via the barrier layer is polished to alternately form the copper embedded wiring and the insulating layer, the barrier layer adjacent to the copper layer is exposed. In the stage (the so-called first polishing step), the problem of copper remaining on the barrier layer (copper residue) and the pits (dents) on the copper wiring become problems as surface irregularities.
　銅残りがあると、その部分が銅残りのない部分に比して盛り上がった状態になり、その後のいわゆる第２研磨工程においてもそのままの形状が維持されやすくなる結果、表面の凹凸が生じやすい。図１には、銅残り２１のある部分が銅残りのない部分２２に比して盛り上がった状態を模式的に示す断面図である。このような銅残りは、配線密度の高い箇所に起こりやすく、その場合には、該当個所の銅配線の厚みが他所に比べて厚いことさえ起こり得る。その様子を図２および３に模式的に示す。図２は配線密度の高い箇所２３に銅残り２１がある状態を示している。このような場合、その後の第２研磨工程においてもその影響が残ると、箇所２３の銅配線の厚みが、銅残りのない部分２２にある銅配線の厚みに比べてより厚くなりやすい。なお、図２および３ではバリア層は記載を省略してある。 If there is a copper residue, the portion is raised as compared with a portion having no copper residue, and the shape is easily maintained in the subsequent so-called second polishing step. As a result, surface irregularities are likely to occur. FIG. 1 is a cross-sectional view schematically showing a state in which a portion having a copper residue 21 is raised as compared with a portion 22 having no copper residue. Such a copper residue is likely to occur at a location where the wiring density is high. In that case, the copper wiring at the corresponding location may even be thicker than other locations. This is schematically shown in FIGS. FIG. 2 shows a state where there is a copper residue 21 at a portion 23 where the wiring density is high. In such a case, if the influence remains in the subsequent second polishing step, the thickness of the copper wiring in the portion 23 tends to be thicker than the thickness of the copper wiring in the portion 22 where there is no copper remaining. In FIGS. 2 and 3, the barrier layer is not shown.
　銅配線上のピットは、恐らく銅の腐食の一種であり、数万倍程度の倍率でやっと見えるほどの微細なものである。 The pits on the copper wiring are probably a kind of copper corrosion and are fine enough to be finally seen at a magnification of about tens of thousands of times.
　銅の研磨に用いられるＣＭＰ用の研磨用組成物としては、ロジンを用いた研磨剤（例えば、特許文献１参照）や、複素環を有する化合物を含有させることにより、エロージョンを抑制する研磨液の発明（例えば、特許文献２参照）が記載されている。さらに、特許文献３には脂肪族カルボン酸とベンゾトリアゾールとを含む研磨液を使用して銅に対する研磨作用を調整することが記載されている。しかし、これらの研磨用組成物では、銅残りを完全には対処できていなかった。 As a polishing composition for CMP used for polishing copper, an abrasive using rosin (see, for example, Patent Document 1) and a polishing liquid that suppresses erosion by containing a compound having a heterocyclic ring. An invention (see, for example, Patent Document 2) is described. Furthermore, Patent Document 3 describes that a polishing liquid containing an aliphatic carboxylic acid and benzotriazole is used to adjust the polishing action on copper. However, these polishing compositions could not completely cope with the copper residue.
国際公開番号　ＷＯ２００７／０７２９１８（クレーム）（US2008-261400）International Publication Number WO2007 / 072918 (Claim) (US2008-261400) 日本国特開２００２－１２８５４号公報（US2002-016275）Japanese Unexamined Patent Publication No. 2002-12854 (US2002-016275) 日本国特開２００２－２３１６６６号公報（US6679929）Japanese Unexamined Patent Publication No. 2002-231666 (US6679929)
　本発明は、上記表面凹凸の課題を解決できる新規な研磨用組成物を提供することを目的とする。本発明のさらに他の目的および利点は、以下の説明から明らかになるであろう。 An object of the present invention is to provide a novel polishing composition that can solve the above-mentioned problem of surface irregularities. Still other objects and advantages of the present invention will become apparent from the following description.
　本発明の第１の態様によれば、絶縁層上にバリア層を介して設けられた銅層を研磨して、銅埋め込み配線と絶縁層とを交互に形成するパターン形成において、前記銅層に隣接した前記バリア層が露出するまで研磨する工程（第１研磨工程）に用いられる研磨用組成物であって、
　ドデシルベンゼンスルホン酸成分と、
　アルケニルコハク酸成分、ポリオキシエチレンアルキルエーテルカルボン酸成分およびポリオキシエチレンアルキルエーテルリン酸成分からなる群から選ばれた少なくとも一つの平坦性向上剤と
を含む、研磨用組成物が提供される。 According to the first aspect of the present invention, in the pattern formation in which the copper layer provided on the insulating layer via the barrier layer is polished to alternately form the copper embedded wiring and the insulating layer, the copper layer A polishing composition used in a step of polishing until the adjacent barrier layer is exposed (first polishing step),
A dodecylbenzenesulfonic acid component;
There is provided a polishing composition comprising at least one flatness improver selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component and a polyoxyethylene alkyl ether phosphoric acid component.
　本発明の第２の態様によれば、更に脂環族樹脂酸を含む、上記態様１に記載の研磨用組成物が提供される。 According to the second aspect of the present invention, there is provided the polishing composition according to the above aspect 1, further comprising an alicyclic resin acid.
　本発明の第３の態様によれば、前記脂環族樹脂酸がロジンである、上記態様２に記載の研磨用組成物が提供される。 According to a third aspect of the present invention, there is provided the polishing composition according to the second aspect, wherein the alicyclic resin acid is rosin.
　本発明の第４の態様によれば、更にイミダゾール誘導体を含む、上記態様１～３のいずれかに記載の研磨用組成物が提供される。 According to the fourth aspect of the present invention, there is provided the polishing composition according to any one of the above aspects 1 to 3, further comprising an imidazole derivative.
　本発明の第５の態様によれば、更に砥粒としてコロイダルシリカを含む、上記態様１～４のいずれかに記載の研磨用組成物が提供される。 According to the fifth aspect of the present invention, there is provided the polishing composition according to any one of the above aspects 1 to 4, further comprising colloidal silica as abrasive grains.
　本発明の第６の態様によれば、更に酸化剤を含む、上記態様１～５のいずれかに記載の研磨用組成物が提供される。 According to the sixth aspect of the present invention, there is provided the polishing composition according to any one of the above aspects 1 to 5, further comprising an oxidizing agent.
　本発明の第７の態様によれば、更に錯体形成剤を含む、上記態様１～６のいずれかに記載の研磨用組成物が提供される。 According to the seventh aspect of the present invention, there is provided the polishing composition according to any one of the above aspects 1 to 6, further comprising a complex-forming agent.
　本発明の第８の態様によれば、研磨用組成物中のオレイン酸の含有量が０．０３質量％以下である、上記態様１～７のいずれかに記載の研磨用組成物が提供される。 According to an eighth aspect of the present invention, there is provided the polishing composition according to any one of the above aspects 1 to 7, wherein the content of oleic acid in the polishing composition is 0.03% by mass or less. The
　本発明の第９の態様によれば、半導体集積回路装置の製造方法であって、
　当該半導体集積回路装置が、溝を有する絶縁層と、当該溝に形成された銅埋め込み配線とを備えており、
　当該絶縁層上にバリア層と銅配線層とがこの順に形成された当該半導体集積回路装置用の多層構造体を、上記態様１～８のいずれかに記載の研磨用組成物を用いて、前記銅層に隣接した前記バリア層が露出するまで研磨することを含む、半導体集積回路装置の製造方法が提供される。 According to a ninth aspect of the present invention, there is provided a method of manufacturing a semiconductor integrated circuit device,
The semiconductor integrated circuit device includes an insulating layer having a groove and a copper embedded wiring formed in the groove,
A multilayer structure for a semiconductor integrated circuit device in which a barrier layer and a copper wiring layer are formed in this order on the insulating layer, using the polishing composition according to any one of the above aspects 1 to 8, There is provided a method of manufacturing a semiconductor integrated circuit device, comprising polishing until the barrier layer adjacent to a copper layer is exposed.
　本発明の第１０の態様によれば、前記バリア層が、Ｔａ、ＴａＮおよびＴｉＮからなる群から選ばれた少なくとも１種を含む、上記態様９に記載の半導体集積回路装置の製造方法が提供される。 According to a tenth aspect of the present invention, there is provided the method for manufacturing a semiconductor integrated circuit device according to the ninth aspect, wherein the barrier layer includes at least one selected from the group consisting of Ta, TaN and TiN. The
　本発明の第１１の態様によれば、前記多層構造体が、前記絶縁層と前記バリア層との間にキャップ層を備えている、上記態様９または１０に記載の半導体集積回路装置の製造方法が提供される。 According to an eleventh aspect of the present invention, the method for manufacturing a semiconductor integrated circuit device according to the ninth or tenth aspect, wherein the multilayer structure includes a cap layer between the insulating layer and the barrier layer. Is provided.
　本発明の第１２の態様によれば、前記溝を有する絶縁層が３以下の比誘電率を有する、上記態様９～１１のいずれかに記載の半導体集積回路装置の製造方法が提供される。 According to a twelfth aspect of the present invention, there is provided the method for manufacturing a semiconductor integrated circuit device according to any one of the above aspects 9 to 11, wherein the insulating layer having the groove has a relative dielectric constant of 3 or less.
　本発明によれば、第１研磨工程における銅配線の研磨速度を良好としつつ、ディッシングの問題を解決し、エロージョンも悪化させずかつ銅残りや銅配線上のピットの問題を解消できる、第１研磨工程用の新規な研磨用組成物が得られる。 According to the present invention, it is possible to solve the problem of dishing while improving the polishing rate of the copper wiring in the first polishing process, and to solve the problem of copper residue and pits on the copper wiring without deteriorating erosion. A novel polishing composition for the polishing process is obtained.
図１は、銅残りのある部分が銅残りのない部分に比して盛り上がった状態を模式的に示す断面図である。FIG. 1 is a cross-sectional view schematically showing a state in which a portion having a copper residue is raised as compared with a portion having no copper residue. 図２は、配線密度の高い箇所に銅残りがある状態を模式的に示す断面図である。FIG. 2 is a cross-sectional view schematically showing a state in which there is a copper residue at a location where the wiring density is high. 図３は、図２の状態の断面を第２研磨工程に供した後の状態を模式的に示す断面図である。FIG. 3 is a cross-sectional view schematically showing a state after the cross section in the state of FIG. 2 is subjected to the second polishing step. 図４（ａ）～（ｃ）は、銅埋込み配線形成工程におけるＣＭＰ工程前後のパターン付きウェハの模式的断面図である。図４（ａ）は研磨前の半導体集積回路の断面図であり、図４（ｂ）は研磨によりディッシングが生じた半導体集積回路の断面図であり、図４（ｃ）は理想的に研磨された半導体集積回路の研磨後の断面図である。4A to 4C are schematic cross-sectional views of the patterned wafer before and after the CMP process in the copper buried wiring forming process. 4A is a cross-sectional view of the semiconductor integrated circuit before polishing, FIG. 4B is a cross-sectional view of the semiconductor integrated circuit in which dishing has occurred by polishing, and FIG. 4C is ideally polished. FIG. 6 is a cross-sectional view after polishing a semiconductor integrated circuit. 図５は、エロージョンを説明するためのパターン付きウェハの概略断面である。FIG. 5 is a schematic cross-sectional view of a patterned wafer for explaining erosion.
　本発明にかかる研磨用組成物の作用を、半導体集積回路の配線用の溝を持つ表面の銅膜を研磨する場合について説明する。以下においては、特に好ましい用途である銅配線を有する半導体集積回路装置に適用する場合を中心に説明するが、本発明に係る研磨用組成物は、銅配線研磨用であれば、その他の場合においても使用できるものであることはいうまでもない。また、以下の説明は本発明を例示するものであり、本発明の範囲を制限するものではなく、本発明の趣旨に合致する限り他の実施の形態も本発明の範疇に属し得ることは言うまでもない。 The operation of the polishing composition according to the present invention will be described in the case of polishing a surface copper film having a groove for wiring of a semiconductor integrated circuit. In the following description, the case where the polishing composition according to the present invention is used for polishing copper wiring will be described. It goes without saying that can also be used. In addition, the following description exemplifies the present invention, does not limit the scope of the present invention, and it goes without saying that other embodiments may also belong to the category of the present invention as long as they match the gist of the present invention. Yes.
　本発明に係る研磨用組成物は、絶縁層上にバリア層を介して設けられた銅層を研磨して、銅埋め込み配線と絶縁層とを交互に形成するパターン形成において、銅層に隣接したバリア層が露出するまでの研磨用組成物、すなわち、第１研磨工程用の研磨用組成物である。なお、第１研磨工程で銅配線以外の銅の部分を除去し、第２研磨工程でバリア層を除去すると共に、たいていの場合には絶縁層と、必要であれば銅の一部を極くわずかに研磨して、絶縁層と銅層とからなる平坦な面が形成される。 The polishing composition according to the present invention is adjacent to the copper layer in pattern formation in which the copper layer provided on the insulating layer via the barrier layer is polished to alternately form the copper embedded wiring and the insulating layer. The polishing composition until the barrier layer is exposed, that is, the polishing composition for the first polishing step. In addition, the copper portion other than the copper wiring is removed in the first polishing step, the barrier layer is removed in the second polishing step, and in most cases, the insulating layer and, if necessary, a part of the copper are extremely used. By polishing slightly, a flat surface composed of an insulating layer and a copper layer is formed.
　なお、表面の凹凸の問題としては、上記の他に、後述するディッシングやエロージョンも知られている。以下において、「平坦性向上」や「平坦化」とは、ディッシングおよびエロージョンの少なくともいずれかが向上することを意味している。 In addition to the above, dishing and erosion described later are also known as problems of surface irregularities. Hereinafter, “improvement of flatness” and “flattening” mean that at least one of dishing and erosion is improved.
　＜使用される材料＞
　以下において、本発明において使用される材料について説明する。研磨前のパターン付きウェハの概略断面を図４（ａ）に示す。図４（ａ）においてＳｉ基板１上に、絶縁層２、バリア層３および配線金属層（銅層）４が形成されている。 <Materials used>
Hereinafter, materials used in the present invention will be described. A schematic cross section of the patterned wafer before polishing is shown in FIG. In FIG. 4A, an insulating layer 2, a barrier layer 3, and a wiring metal layer (copper layer) 4 are formed on a Si substrate 1.
　＜絶縁層＞
　絶縁層としては、以下記載の、テトラエトキシシラン、シラン等を用いたプラズマＣＶＤによるＳｉＯ２膜、低誘電率材料膜（ＳｉＯＦ膜、有機ＳＯＧ膜等）、さらにこれらとキャップ層と組み合わせた構成、の全てがあり得る。 <Insulating layer>
As the insulating layer, a SiO 2 film by plasma CVD using tetraethoxysilane, silane or the like, a low dielectric constant material film (SiOF film, organic SOG film, etc.), and a combination of these with a cap layer, All of these are possible.
　本発明に係る研磨用組成物による研磨対象の一つである絶縁層を構成する材料としては、公知のどのようなものを使用してもよい。このような材料としては、二酸化ケイ素膜を例示できる。二酸化ケイ素膜としては、一般にはＳｉとＯとの架橋構造よりなり、ＳｉとＯの原子数の比が１：２のものが使用されるが、これ以外のものでもよい。このような二酸化ケイ素膜としてはテトラエトキシシラン（ＴＥＯＳ）やシランガス（ＳｉＨ４）を用い、プラズマＣＶＤにより堆積させたものが一般的に知られている。 Any known material may be used as the material constituting the insulating layer that is one of the objects to be polished by the polishing composition according to the present invention. An example of such a material is a silicon dioxide film. As the silicon dioxide film, a film having a crosslinked structure of Si and O and having a ratio of the number of atoms of Si and O of 1: 2 is generally used, but other films may be used. As such a silicon dioxide film, a film deposited by plasma CVD using tetraethoxysilane (TEOS) or silane gas (SiH 4 ) is generally known.
　また、近年、信号遅延の抑制を目的としてこの二酸化ケイ素膜の他、比誘電率が３以下の低誘電率材料からなる膜が絶縁層として使用されるようになってきている。このような低誘電率材料膜としては、フッ素添加酸化ケイ素（ＳｉＯＦ）からなる膜、有機ＳＯＧ膜（Ｓｐｉｎ　ｏｎ　ｇｌａｓｓにより得られる有機成分を含む膜）、ポーラスシリカ膜等の低誘電率材料膜や主にＳｉ－Ｏ結合から構成され、ＣＨ３結合を含む有機ケイ素材料（一般にＳｉＯＣと表記される）膜が知られている。これらの膜も本発明に係る研磨用組成物を適用する絶縁層として好適に使用できる。 In recent years, in addition to this silicon dioxide film, a film made of a low dielectric constant material having a relative dielectric constant of 3 or less has been used as an insulating layer for the purpose of suppressing signal delay. Examples of such a low dielectric constant material film include a film made of fluorine-added silicon oxide (SiOF), an organic SOG film (a film containing an organic component obtained by Spin on glass), a low dielectric constant material film such as a porous silica film, An organic silicon material (generally referred to as SiOC) film that is mainly composed of Si—O bonds and includes CH 3 bonds is known. These films can also be suitably used as an insulating layer to which the polishing composition according to the present invention is applied.
　有機ケイ素材料は、プロセス技術として従来技術の延長線上にあり、適切なプロセスチューニングを行うことにより適応範囲の広い量産技術が達成されている。したがって、この低誘電率材料を使用した膜を平坦化する技術が要望されており、本発明に係る研磨用組成物を好適に使用できる。 Organic silicon materials are an extension of conventional technology as process technology, and mass production technology with a wide range of application has been achieved by performing appropriate process tuning. Therefore, a technique for flattening a film using this low dielectric constant material is desired, and the polishing composition according to the present invention can be suitably used.
　低誘電率材料である有機ケイ素材料としては、商品名：Ｂｌａｃｋ　Ｄｉａｍｏｎｄ（比誘電率２．７、アプライドマテリアルズ社技術）、商品名Ｃｏｒａｌ（比誘電率２．７、Ｎｏｖｅｌｌｕｓ　Ｓｙｓｔｅｍｓ社技術）、Ａｕｒｏｒａ２．７（比誘電率２．７、日本ＡＳＭ社技術）等を挙げることができ、とりわけＳｉ－ＣＨ３結合を有する化合物が好ましく用いられる。 As an organic silicon material which is a low dielectric constant material, trade name: Black Diamond (relative permittivity 2.7, Applied Materials technology), trade name Coral (relative permittivity 2.7, Novellus Systems technology), Aurora 2 7 (relative permittivity 2.7, Japan ASM Co., Ltd. technology) and the like, and a compound having a Si—CH 3 bond is particularly preferably used.
　＜キャップ層＞
　本発明に係る研磨用組成物は、絶縁層上にキャップ層が形成された場合についても好適に使用できる。たとえば、低誘電率絶縁層上にキャップ層、バリア層および金属配線層を順次積層してなる多層構造において、キャップ層を完全に除去した後、絶縁層を削り込んで平坦化する場合にも適用できる。 <Cap layer>
The polishing composition according to the present invention can also be suitably used when a cap layer is formed on an insulating layer. For example, in a multilayer structure in which a cap layer, a barrier layer, and a metal wiring layer are sequentially stacked on an insulating layer with a low dielectric constant, the cap layer is completely removed and then the insulating layer is shaved and flattened. it can.
　キャップ層は、絶縁層に低誘電率材料を使用する場合に、絶縁層とバリア層との密着性を高めたり、化学的機械的に脆弱な低誘電率絶縁層に金属配線層を埋め込むための溝をエッチングにより形成する際のマスク材として用いたり、低誘電率材料の変質防止を図ることを目的として設けられる層である。 The cap layer is used to increase the adhesion between the insulating layer and the barrier layer when a low dielectric constant material is used for the insulating layer, or to embed a metal wiring layer in the low dielectric constant insulating layer that is chemically and mechanically fragile. It is a layer provided for the purpose of using as a mask material when the groove is formed by etching or for preventing deterioration of the low dielectric constant material.
　キャップ層としては、一般にケイ素と酸素とを構成要素とする膜が使用される。このような膜としては二酸化ケイ素膜を例示できる。二酸化ケイ素膜としては、一般にはＳｉとＯとの架橋構造よりなり、ＳｉとＯの原子数の比が１：２のものが使用されるが、これ以外のものでもよい。このような二酸化ケイ素膜としてはテトラエトキシシラン（ＴＥＯＳ）やシランガス（ＳｉＨ４）を用い、プラズマＣＶＤにより堆積させたものが一般的に知られている。 As the cap layer, a film having silicon and oxygen as constituent elements is generally used. An example of such a film is a silicon dioxide film. As the silicon dioxide film, a film having a crosslinked structure of Si and O and having a ratio of the number of atoms of Si and O of 1: 2 is generally used, but other films may be used. As such a silicon dioxide film, a film deposited by plasma CVD using tetraethoxysilane (TEOS) or silane gas (SiH 4 ) is generally known.
　＜バリア層＞
　バリア層とは、絶縁層上に、たとえばスパッタ法により製膜された、Ｔａ、ＴａＮ、ＴｉＮからなる群から選ばれる少なくとも１種を含む層で、銅層から絶縁層への銅の拡散を妨げる目的で配置されるが、本発明においては銅層の研磨において、その配線部が現れる時点を見出すためのストッパーとしての役目も果たしている。 <Barrier layer>
The barrier layer is a layer containing at least one selected from the group consisting of Ta, TaN, and TiN formed on the insulating layer by, for example, a sputtering method, and hinders diffusion of copper from the copper layer to the insulating layer. Although arranged for the purpose, in the present invention, in polishing the copper layer, it also serves as a stopper for finding a point in time when the wiring portion appears.
　＜銅層＞
　銅層は絶縁層上にバリア層を介して製膜される。その製膜方法としては、バリア層製膜後にスパッタ法によりＣｕシード層を１００ｎｍ厚程製膜し、更にそのＣｕシード層上に電解メッキ法によりＣｕ層を形成する方法を例示できる。 <Copper layer>
The copper layer is formed on the insulating layer via a barrier layer. Examples of the film forming method include a method of forming a Cu seed layer to a thickness of about 100 nm by sputtering after forming the barrier layer, and further forming a Cu layer on the Cu seed layer by electrolytic plating.
　本発明によれば、銅を配線用金属として用いた場合に精度の高い表面平坦化を実現できる。このため、ディッシングやエロージョンの少ない、平坦性に優れる表面状態を有する半導体集積回路を得ることができ、半導体集積回路の多層化、細線化にとって極めて有効である。このことを更に詳しく説明すると次のようである。 According to the present invention, highly accurate surface flattening can be realized when copper is used as a wiring metal. For this reason, a semiconductor integrated circuit having a surface state with less dishing and erosion and excellent flatness can be obtained, which is extremely effective for multilayering and thinning of the semiconductor integrated circuit. This will be described in more detail as follows.
　一般的に、大口径のウェハを研磨する場合には、面内の膜厚分布やパッドへの研磨圧力の不均一などが避けられないため、面内全面を均一に研磨することは難しい。そのため絶縁層上にバリア層を介して設けられた銅層を研磨していくと、まずウエハ面内の一部について銅層に隣接したバリア層が露出する。そして、ウエハ全面にわたってバリア層上の銅膜を除去するために引き続き研磨（オーバー研磨という）をおこなうと、従来技術の研磨剤を用いた研磨では、順次露出された銅埋込み配線のディッシングが進む問題があった。 In general, when polishing a large-diameter wafer, it is difficult to uniformly polish the entire surface within the surface because in-plane film thickness distribution and uneven polishing pressure on the pad are inevitable. Therefore, when the copper layer provided on the insulating layer via the barrier layer is polished, first, the barrier layer adjacent to the copper layer is exposed for a part of the wafer surface. Then, if polishing (hereinafter referred to as over-polishing) is subsequently performed to remove the copper film on the barrier layer over the entire wafer surface, the polishing using the conventional polishing agent will cause dishing of the exposed copper embedded wiring sequentially. was there.
　すなわち、バリア層が露出した時点でのディッシング量が大きかったり、第１研磨工程を終え、オーバー研磨により余剰の銅層を除去した時点でディッシング量が大きくばらつきを生じたり、更に、場合によってはエロージョンも発生していた。そのため、従来は、第２研磨工程において、バリア層を削ったのち、絶縁層と銅配線の一部をさらに削り込んで、銅配線と絶縁層とを平滑に仕上げる必要があった。しかしながら、第２研磨工程の研磨量を大きくすると、研磨の面内分布により配線溝の深さが不足する箇所が生じたり、新たに銅配線のディッシングを生じたりするおそれがあった。なお、エロージョンとは、細い配線部や密集した配線部で発生しやすいもので、図５に示すように配線パターンのない絶縁層部分（Ｇｌｏｂａｌ部）に比べ、配線部の絶縁層が過剰に研磨され、絶縁層が部分的に薄くなる現象をいう。すなわち、Ｇｌｏｂａｌ部２０よりもさらに研磨されたエロージョン部分１８が生じる。なお、図５においては、バリア層は省略している。 That is, the dishing amount at the time when the barrier layer is exposed is large, the dishing amount varies greatly after the first polishing step is completed and the excess copper layer is removed by overpolishing, and in some cases, the erosion Also occurred. For this reason, conventionally, in the second polishing step, after the barrier layer is shaved, it is necessary to further grind a part of the insulating layer and the copper wiring to finish the copper wiring and the insulating layer smoothly. However, when the amount of polishing in the second polishing step is increased, there may be a portion where the depth of the wiring groove is insufficient due to the in-plane distribution of polishing, or dishing of the copper wiring may be newly generated. Note that erosion is likely to occur in thin wiring portions and dense wiring portions. As shown in FIG. 5, the insulating layer in the wiring portion is excessively polished as compared with the insulating layer portion (Global portion) having no wiring pattern. This is a phenomenon in which the insulating layer is partially thinned. That is, an erosion portion 18 that is further polished than the global portion 20 is generated. In FIG. 5, the barrier layer is omitted.
　これに対し、本願発明の研磨用組成物を用いると、オーバー研磨により銅配線が必要以上に研磨されないので、第１研磨工程で、ディッシングを進行させたり、エロージョンを生じたりすることなく余裕をもってオーバー研磨することができる。それにより、８インチ以上という大口径のウェハであっても、オーバー研磨によりウェハ面内全面に渡って平滑かつ均一に余剰の銅層を除去して第１研磨工程を終えた時点でのディッシング量を５５ｎｍ以下とすることができるという顕著な効果が得られる。 On the other hand, when the polishing composition of the present invention is used, the copper wiring is not polished more than necessary by over-polishing, so that the first polishing step does not cause dishing and does not cause erosion. Can be polished. As a result, even when the wafer has a large diameter of 8 inches or more, the amount of dishing at the time when the first polishing process is completed by removing the excess copper layer smoothly and uniformly over the entire wafer surface by over-polishing. Has a remarkable effect that the thickness can be 55 nm or less.
　更に、第２研磨工程で絶縁層と銅層とを余分に削りこまなくて良いので、絶縁層、銅層を薄くし、トレンチ加工量（配線の溝の削り量）を浅くし、研磨量を少なくすることができる。それにより全体の工程を短時間でおこなえるのでコストダウンが可能で、配線溝深さのばらつきや銅配線のディッシングを抑制できるという効果も得られる。 Furthermore, since it is not necessary to cut away the insulating layer and the copper layer excessively in the second polishing step, the insulating layer and the copper layer are thinned, the trench processing amount (wiring groove cutting amount) is shallow, and the polishing amount is reduced. Can be reduced. As a result, the entire process can be performed in a short time, so that the cost can be reduced, and the effects of suppressing variations in the wiring groove depth and dishing of the copper wiring can also be obtained.
　＜研磨用組成物＞
　以下、本発明に係る研磨用組成物に使用し得る各種材料について述べる。 <Polishing composition>
Hereinafter, various materials that can be used in the polishing composition according to the present invention will be described.
　本研磨用組成物は、ドデシルベンゼンスルホン酸成分を必ず含有し、更に、アルケニルコハク酸成分、ポリオキシエチレンアルキルエーテルカルボン酸成分およびポリオキシエチレンアルキルエーテルリン酸成分からなる群から選ばれた少なくとも一つを平坦性向上剤として含む。 The polishing composition necessarily contains a dodecylbenzenesulfonic acid component, and at least one selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component and a polyoxyethylene alkyl ether phosphoric acid component. One as a flatness improver.
　「成分」としたのは、酸それ自体はもちろんのこと、酸そのものの他、塩の形態も含まれ得ることを意味するためである。塩の形態は、酸を使用した結果、別途加えられた塩基性物質と反応して生じる場合も、塩の形態で加えられた場合もあるが、酸として添加した結果別途加えられた塩基性物質と反応して生じるものが一般的である。具体的には、本研磨用組成物には塩基性物質として水酸化カリウムが使用されることが多いため、酸として添加されたものの少なくとも一部はこの水酸化カリウムと反応して塩の形態になっているものと考えられる。 The term “component” is intended to mean that not only the acid itself but also the salt form can be included in addition to the acid itself. The salt form may be generated by reacting with a basic substance added separately as a result of using an acid, or may be added in the form of a salt, but the basic substance added separately as a result of addition as an acid. What is produced by reacting with is common. Specifically, since potassium hydroxide is often used as a basic substance in the polishing composition, at least a part of what is added as an acid reacts with the potassium hydroxide to form a salt. It is thought that.
　本発明においては、ドデシルベンゼンスルホン酸成分を必ず含有し、更に、アルケニルコハク酸成分、ポリオキシエチレンアルキルエーテルカルボン酸成分およびポリオキシエチレンアルキルエーテルリン酸成分からなる群から選ばれた少なくとも一つの平坦性向上剤として含むと、銅残りやピットを抑制できることが判明した。更に、従来の研磨剤に比べ、ディッシングと呼ばれる、配線部分を平坦面より低く削り取ってしまう現象も悪化しないことが判明した。さらに、本発明の上記平坦性向上剤を添加すると、センター部（センターチップ）のみならず、エッジ部（エッジチップ）も良好とできる点ですぐれている。また、エロージョンの悪化も見られない。 In the present invention, a dodecylbenzenesulfonic acid component is necessarily contained, and at least one flat selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component, and a polyoxyethylene alkyl ether phosphoric acid component. It has been found that copper residues and pits can be suppressed when included as a property improver. Furthermore, it has been found that the phenomenon called dishing, which scrapes the wiring portion lower than the flat surface, does not deteriorate as compared with conventional abrasives. Furthermore, when the flatness improving agent of the present invention is added, not only the center part (center chip) but also the edge part (edge chip) can be improved. Moreover, the deterioration of erosion is not seen.
　その理由は定かではないが、従来の研磨剤に多用されているオレイン酸を使用しないと、銅残りは抑制できるが、ディッシングは悪化しやすい一方、オレイン酸を必要以上に使用すると、ディッシングは抑制できるが銅残りが生じやすい。上記知見から推測するに、上記成分は、銅の保護膜形成剤の働きを有する脂環族樹脂酸（例えばロジン）のディッシング防止作用を阻害しないあるいはロジンのディッシング防止作用に寄与すると同時に、銅のスムーズな研磨を妨げないあるいは促進する作用を有しているものと思われる。 The reason is not clear, but if you do not use oleic acid, which is often used in conventional abrasives, copper residue can be suppressed, but dishing tends to deteriorate, but if you use oleic acid more than necessary, dishing is suppressed. Although copper residue is likely to occur. As estimated from the above findings, the above component does not inhibit the anti-dishing action of the alicyclic resin acid (for example, rosin) having the function of a copper protective film forming agent or contributes to the anti-dishing action of rosin. It seems to have an action that does not prevent or promote smooth polishing.
　上記の議論から理解できるように、本研磨用組成物中にオレイン酸をある程度以上含まないことが好ましく、具体的には、オレイン酸の含有量は、０．０３質量％以下、特に０．０１質量％以下が好ましい。 As can be understood from the above discussion, it is preferable that the polishing composition does not contain oleic acid to some extent. Specifically, the content of oleic acid is 0.03% by mass or less, particularly 0.01%. The mass% or less is preferable.
　＜ドデシルベンゼンスルホン酸成分＞
　ドデシルベンゼンスルホン酸成分は、具体的には、ドデシルベンゼンスルホン酸（下式参照）、ドデシルベンゼンスルホン酸ナトリウム塩、ドデシルベンゼンスルホン酸カルシウム塩などが例示される。なお、ドデシル基の炭素鎖は、直鎖であっても分岐していてもよい。 <Dodecylbenzenesulfonic acid component>
Specific examples of the dodecylbenzenesulfonic acid component include dodecylbenzenesulfonic acid (see the following formula), sodium dodecylbenzenesulfonate, calcium dodecylbenzenesulfonate, and the like. Note that the carbon chain of the dodecyl group may be linear or branched.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　なお、ドデシルベンゼンスルホン酸は、本発明においては、脂環族樹脂酸、特にロジンの溶解助剤としての働きを有し、研磨用組成物を高濃度に濃縮できる点で非常に優れている。なお、研磨剤組成物は、その運搬の容易性のニーズの高まりため、濃縮して運搬し、実際の研磨直前に希釈することが好ましい。よって、高濃度に濃縮できる点は大きな利点となる。 In the present invention, dodecylbenzenesulfonic acid has a function as a solubilizing agent for alicyclic resin acids, particularly rosin, and is excellent in that the polishing composition can be concentrated at a high concentration. In addition, it is preferable to concentrate and convey an abrasive | polishing agent composition, and to dilute just before actual grinding | polishing in order for the needs of the ease of the conveyance to increase. Therefore, the point which can concentrate to high concentration becomes a big advantage.
　本研磨用組成物中のドデシルベンゼンスルホン酸成分の含有量は、０．００２～０．２質量％、さらには０．００５～０．１５質量％、０．００５～０．１質量％であることが、効率的に本研磨用組成物を濃縮できるため好ましい。 The content of the dodecylbenzenesulfonic acid component in the polishing composition is 0.002 to 0.2% by mass, further 0.005 to 0.15% by mass, and 0.005 to 0.1% by mass. It is preferable because the polishing composition can be concentrated efficiently.
　＜アルケニルコハク酸成分＞
　アルケニルコハク酸成分は、具体的には、アルケニルコハク酸、アルケニルコハク酸ジカリウム塩、アルケニルコハク酸ジカリウム、アルケニルコハク酸無水物などが例示される。このアルケニルコハク酸を用いることで、ディッシングを効果的に防止することが可能であり、少量で効果がみられる点で優れている。アルケニルコハク酸成分と脂環族樹脂酸、特にロジンとを一緒に用いることで大きく平坦性が向上する。その理由は正確には分かっていないが、アルケニルコハク酸成分と脂環族樹脂酸とが、何らかの化学的相乗効果を有するためと推測している。 <Alkenyl succinic acid component>
Specific examples of the alkenyl succinic acid component include alkenyl succinic acid, alkenyl succinic acid dipotassium salt, alkenyl succinic acid dipotassium, alkenyl succinic anhydride and the like. By using this alkenyl succinic acid, dishing can be effectively prevented, and it is excellent in that the effect is seen in a small amount. Flatness is greatly improved by using an alkenyl succinic acid component and an alicyclic resin acid, particularly rosin. The reason is not exactly known, but it is assumed that the alkenyl succinic acid component and the alicyclic resin acid have some chemical synergistic effect.
　本研磨用組成物中のアルケニルコハク酸成分の含有量は、０．０００５～０．０１質量％、さらには０．０００７～０．００８質量％、０．０００７～０．００６質量％であることが、効果的にディッシングを防止できるため好ましい。また、アルケニルコハク酸成分と脂環族樹脂酸との含有量比（質量比）は、１：８０～１：５、特に１：６０～１：３であることが、ディッシングを防止しつつ、銅残りやピットを改善できるため好ましい。 The content of the alkenyl succinic acid component in the polishing composition is 0.0005 to 0.01% by mass, more preferably 0.0007 to 0.008% by mass, and 0.0007 to 0.006% by mass. However, it is preferable because dishing can be effectively prevented. The content ratio (mass ratio) of the alkenyl succinic acid component and the alicyclic resin acid is 1:80 to 1: 5, particularly 1:60 to 1: 3, while preventing dishing. It is preferable because copper residue and pits can be improved.
　＜ポリオキシエチレンアルキルエーテルカルボン酸成分＞
　ポリオキシエチレンアルキルエーテルカルボン酸成分としては、具体的には、ポリオキシエチレン（３）トリデシルエーテル酢酸、ポリオキシエチレン（７）トリデシルエーテル酢酸、ポリオキシエチレン（６）トリデシルエーテル酢酸、ポリオキシエチレン（３）トリデシルエーテル酢酸ナトリウム、ポリオキシエチレン（７）トリデシルエーテル酢酸ナトリウム、ポリオキシエチレン（６）トリデシルエーテル酢酸ナトリウム、ポリオキシエチレン（４．５）ラウリルエーテル酢酸およびポリオキシエチレン（１０）ラウリルエーテル酢酸などが例示される。ポリオキシエチレンアルキルエーテルカルボン酸成分と脂環族樹脂酸、特にロジンとを一緒に用いることで大きく平坦性が向上する。その理由は正確には分かっていないが、ポリオキシエチレンアルキルエーテルカルボン酸成分と脂環族樹脂酸とが、何らかの化学的相乗効果を有するためと推測している。ポリオキシエチレンアルキルエーテルカルボン酸成分は、濃度の温度依存性が少なく、銅に対する研磨性能が優れている点で好ましい。また、ドデシルベンゼンスルホン酸成分とポリオキシエチレンアルキルエーテルカルボン酸成分とを両方含むことで、さらなる濃縮ができる点で好ましい。 <Polyoxyethylene alkyl ether carboxylic acid component>
Specific examples of the polyoxyethylene alkyl ether carboxylic acid component include polyoxyethylene (3) tridecyl ether acetic acid, polyoxyethylene (7) tridecyl ether acetic acid, polyoxyethylene (6) tridecyl ether acetic acid, poly Oxyethylene (3) tridecyl ether sodium acetate, polyoxyethylene (7) sodium tridecyl ether acetate, polyoxyethylene (6) sodium tridecyl ether acetate, polyoxyethylene (4.5) lauryl ether acetic acid and polyoxyethylene (10) Lauryl ether acetic acid and the like are exemplified. By using a polyoxyethylene alkyl ether carboxylic acid component and an alicyclic resin acid, particularly rosin, flatness is greatly improved. Although the reason is not exactly known, it is assumed that the polyoxyethylene alkyl ether carboxylic acid component and the alicyclic resin acid have some chemical synergistic effect. The polyoxyethylene alkyl ether carboxylic acid component is preferable in that the temperature dependency of the concentration is small and the polishing performance for copper is excellent. Moreover, it is preferable at the point which can be further concentrated by including both a dodecylbenzenesulfonic acid component and a polyoxyethylene alkyl ether carboxylic acid component.
　なお、上記において括弧内の数字は、オキシエチレン基の繰り返しの数を示す。たとえば、ポリオキシエチレン（３）トリデシルエーテル酢酸とは、３つのオキシエチレン結合からなるポリオキシエチレン部分と、トリデシルエーテル酢酸とからなる物質であることを意味する。一般的には、ポリオキシエチレン（ｎ）アルキルエーテルカルボン酸はＲＯ－（Ｃ２Ｈ２Ｏ）ｎ－ＣＨ２ＣＯＯＨと表すことができる。Ｒは１０～１５個の炭素からなるアルキル基であり、直鎖であっても分鎖であってもよい。 In the above, the numbers in parentheses indicate the number of repeating oxyethylene groups. For example, polyoxyethylene (3) tridecyl ether acetic acid means a substance consisting of a polyoxyethylene moiety consisting of three oxyethylene bonds and tridecyl ether acetic acid. In general, polyoxyethylene (n) alkyl ether carboxylic acids can be represented as RO- (C 2 H 2 O) n —CH 2 COOH. R is an alkyl group composed of 10 to 15 carbons, and may be linear or branched.
　本研磨用組成物中のポリオキシエチレンアルキルエーテルカルボン酸成分の含有量は、０．００５～０．１質量％、さらには０．０１～０．０７質量％、であることが、効果的にディッシングを防止できるため好ましい。また、ポリオキシエチレンアルキルエーテルカルボン酸成分と脂環族樹脂酸との含有量比（質量比）は、２：１～１：５、特に１：１～１：３であることが、ディッシングを防止しつつ、銅残りを改善できるため好ましい。
また、ポリオキシエチレンアルキルエーテルカルボン酸成分とドデシルベンゼンスルホン酸との比は、５：１～１：５であることが好ましく、３：１～１：３であることがさらに好ましい。 It is effective that the content of the polyoxyethylene alkyl ether carboxylic acid component in the polishing composition is 0.005 to 0.1% by mass, more preferably 0.01 to 0.07% by mass. It is preferable because dishing can be prevented. Further, the content ratio (mass ratio) of the polyoxyethylene alkyl ether carboxylic acid component and the alicyclic resin acid is 2: 1 to 1: 5, particularly 1: 1 to 1: 3. It is preferable because the copper residue can be improved while preventing.
The ratio of the polyoxyethylene alkyl ether carboxylic acid component to dodecylbenzene sulfonic acid is preferably 5: 1 to 1: 5, and more preferably 3: 1 to 1: 3.
　＜ポリオキシエチレンアルキルエーテルリン酸成分＞
　ポリオキシエチレンアルキルエーテルリン酸成分とは、具体的には、ポリオキシエチレン（１０）ラウリルエーテルリン酸、ジポリオキシエチレン（１０）ラウリルエーテルリン酸、ポリオキシエチレン（８）オレイルエーテルリン酸、ジポリオキシエチレン（８）オレイルエーテルリン酸、ポリオキシエチレン（２）（Ｃ１２－１５）アルキルエーテルリン酸、ポリオキシエチレン（４）（Ｃ１２－１５）アルキルエーテルリン酸、ポリオキシエチレン（８）（Ｃ１２－１５）アルキルエーテルリン酸、ポリオキシエチレン（１０）（Ｃ１２－１５）アルキルエーテルリン酸、トリポリオキシエチレン（４）ラウリルエーテルリン酸、ポリオキシエチレン（１）ラウリルエーテルリン酸およびこれらの塩が例示される。ポリオキシエチレンアルキルエーテルリン酸成分と脂環族樹脂酸、特にロジンとを一緒に用いることで大きく平坦性が向上する。その理由は正確には分かっていないが、ポリオキシエチレンアルキルエーテルリン酸成分と脂環族樹脂酸とが、何らかの化学的相乗効果を有するためと推測している。 <Polyoxyethylene alkyl ether phosphate component>
Specific examples of the polyoxyethylene alkyl ether phosphate component include polyoxyethylene (10) lauryl ether phosphate, dipolyoxyethylene (10) lauryl ether phosphate, polyoxyethylene (8) oleyl ether phosphate, Dipolyoxyethylene (8) oleyl ether phosphoric acid, polyoxyethylene (2) (C 12-15 ) alkyl ether phosphoric acid, polyoxyethylene (4) (C 12-15 ) alkyl ether phosphoric acid, polyoxyethylene ( 8) (C 12-15 ) alkyl ether phosphoric acid, polyoxyethylene (10) (C 12-15 ) alkyl ether phosphoric acid, tripolyoxyethylene (4) lauryl ether phosphoric acid, polyoxyethylene (1) lauryl ether phosphor Examples are acids and their salts. By using a polyoxyethylene alkyl ether phosphoric acid component and an alicyclic resin acid, particularly rosin, flatness is greatly improved. The reason is not exactly known, but it is assumed that the polyoxyethylene alkyl ether phosphoric acid component and the alicyclic resin acid have some chemical synergistic effect.
　なお、上記において、括弧内の数字は、オキシエチレン基の繰り返しの数を示す。たとえば、ポリオキシエチレン（８）オレイルエーテルリン酸とは、８つのオキシエチレン結合からなるポリオキシエチレン部分と、オレイルエーテルリン酸部分とからなることを意味する。一般的には、ポリオキシエチレン（ｎ）ラウリルエーテルリン酸はＣ１２Ｈ２５Ｏ－（Ｃ２Ｈ２Ｏ）ｎ－Ｈ２ＰＯ４と表すことができる。また、（Ｃ１２－１５）とは、アルキル基の構造を表しており、具体的には、炭素を１２～１５個有するアルキル基であることを示す。 In the above, the numbers in parentheses indicate the number of repeating oxyethylene groups. For example, polyoxyethylene (8) oleyl ether phosphoric acid means that it consists of a polyoxyethylene moiety consisting of eight oxyethylene bonds and an oleyl ether phosphate moiety. In general, polyoxyethylene (n) lauryl ether phosphoric acid can be represented as C 12 H 25 O— (C 2 H 2 O) n —H 2 PO 4 . (C 12-15 ) represents the structure of an alkyl group, specifically an alkyl group having 12 to 15 carbon atoms.
　本研磨用組成物中のポリオキシエチレンアルキルエーテルリン酸成分の含有量は、０．００５～０．１質量％、さらには０．０１～０．０５質量％であることが、効果的にディッシングを防止できるため好ましい。また、ポリオキシエチレンアルキルエーテルリン酸成分と脂環族樹脂酸との含有量比（質量比）は、２：１～１：５、特に１：１～１：３であることが、ディッシングを防止しつつ、銅残りを改善できるため好ましい。 It is effective that the content of the polyoxyethylene alkyl ether phosphoric acid component in the polishing composition is 0.005 to 0.1% by mass, more preferably 0.01 to 0.05% by mass. Can be prevented. Further, the content ratio (mass ratio) of the polyoxyethylene alkyl ether phosphoric acid component and the alicyclic resin acid is 2: 1 to 1: 5, particularly 1: 1 to 1: 3. It is preferable because the copper residue can be improved while preventing.
　アルケニルコハク酸成分、ポリオキシエチレンアルキルエーテルカルボン酸成分およびポリオキシエチレンアルキルエーテルリン酸成分は、すべて含有していてもよいし、一つの成分のみが含有していてもよい。アルケニルコハク酸成分は、他の成分と比較して、非常に少量で同等の効果を有するため、本研磨用組成物の粘度が必要以上に上がることを防止できる。また、ポリオキシエチレンアルキルエーテルカルボン酸成分は、研磨速度を良好に維持できる点、および研磨安定性の点で最もすぐれている。なお、本明細書においては、アルケニルコハク酸成分、ポリオキシエチレンアルキルエーテルカルボン酸成分およびポリオキシエチレンアルキルエーテルリン酸成分は全て研磨面の平坦化に寄与し得るので、平坦性向上剤と呼称される。 The alkenyl succinic acid component, polyoxyethylene alkyl ether carboxylic acid component and polyoxyethylene alkyl ether phosphoric acid component may all be contained, or only one component may be contained. Since the alkenyl succinic acid component has the same effect in a very small amount as compared with other components, the viscosity of the polishing composition can be prevented from rising more than necessary. The polyoxyethylene alkyl ether carboxylic acid component is most excellent in terms of maintaining a good polishing rate and in terms of polishing stability. In the present specification, the alkenyl succinic acid component, the polyoxyethylene alkyl ether carboxylic acid component and the polyoxyethylene alkyl ether phosphoric acid component can all contribute to the flattening of the polished surface, and are therefore referred to as flatness improvers. The
　本研磨用組成物は粘度が低い点で好ましい。粘度はＣＭＰのような技術分野では予想以上に重要な要素である。というのも、一般的に、研磨するときの条件を一定とすることは、安定的な研磨を行う上で非常に重要である。しかし、あまりに研磨用組成物の粘度が高すぎると、研磨剤の搬送系で詰まりが生じたり、研磨剤が残ったりということがありうる。よって、長期間の研磨中ずっと同様の条件で研磨を行うことができるかどうかは、研磨剤の粘度によるところが大きい。なお、粘度を良好とするためには、水溶性高分子を含まないことが好ましく、具体的には、研磨用組成物中に、０．１質量％以下、特に０．０５質量％以下、さらには０．０３質量％以下であることが、必要以上に研磨速度を下げることを防止でき好ましい。水溶性高分子とは、分子量が５０００以上の水溶性の高分子である。 This polishing composition is preferable in terms of low viscosity. Viscosity is a more important factor than expected in technical fields such as CMP. This is because it is generally very important to make the polishing conditions constant in order to perform stable polishing. However, when the viscosity of the polishing composition is too high, clogging may occur in the abrasive conveyance system or the abrasive may remain. Therefore, whether or not polishing can be performed under the same conditions during long-term polishing largely depends on the viscosity of the abrasive. In order to improve the viscosity, it is preferable not to contain a water-soluble polymer. Specifically, in the polishing composition, 0.1% by mass or less, particularly 0.05% by mass or less, Is preferably 0.03% by mass or less because it is possible to prevent the polishing rate from being lowered more than necessary. The water-soluble polymer is a water-soluble polymer having a molecular weight of 5000 or more.
　＜錯体形成剤＞
　本研磨用組成物は、錯体形成剤を含んでいてもよい。錯体形成剤とは、銅と錯体を形成する物質を意味する。錯体形成剤を含有させることにより、その機構は明らかでないが銅の研磨速度が増大する。具体的には、以下のとおりである。 <Complex forming agent>
The polishing composition may contain a complex forming agent. The complex forming agent means a substance that forms a complex with copper. Inclusion of the complexing agent increases the copper polishing rate, although the mechanism is not clear. Specifically, it is as follows.
　含窒素複素環基を有するカルボン酸（モノカルボン酸、ポリカルボン酸）：２－ピリジンカルボン酸、３－ピリジンカルボン酸、４－ピリジンカルボン酸、２，３－ピリジンジカルボン酸、２，４－ピリジンジカルボン酸、２，５－ピリジンジカルボン酸、２，６－ピリジンジカルボン酸、３，４－ピリジンジカルボン酸、３，５－ピリジンジカルボン酸、ピラジンカルボン酸、２，３－ピラジンジカルボン酸、２－キノリンカルボン酸（キナルジン酸）、３－キノリンカルボン酸、４－キノリンカルボン酸、８－キノリンカルボン酸。 Carboxylic acid having a nitrogen-containing heterocyclic group (monocarboxylic acid, polycarboxylic acid): 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, 2,3-pyridinedicarboxylic acid, 2,4-pyridine Dicarboxylic acid, 2,5-pyridinedicarboxylic acid, 2,6-pyridinedicarboxylic acid, 3,4-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, pyrazinecarboxylic acid, 2,3-pyrazinedicarboxylic acid, 2-quinoline Carboxylic acid (quinaldic acid), 3-quinoline carboxylic acid, 4-quinoline carboxylic acid, 8-quinoline carboxylic acid.
　アミノ基を有するカルボン酸（アミノ酸など）：アラニン、グリシン、プロリン、フェニルアラニン。 Carboxylic acid having amino group (amino acid etc.): alanine, glycine, proline, phenylalanine.
　水酸基を有するカルボン酸（ヒドロキシカルボン酸など）：乳酸、リンゴ酸、クエン酸、イソクエン酸、酒石酸、グリコール酸、グルコン酸、サリチル酸。 Carboxylic acid having a hydroxyl group (such as hydroxycarboxylic acid): lactic acid, malic acid, citric acid, isocitric acid, tartaric acid, glycolic acid, gluconic acid, salicylic acid.
　上記以外のポリカルボン酸：シュウ酸、マロン酸、コハク酸、フマル酸、マレイン酸、オキサル酢酸、グルタル酸、アジピン酸、シトラコン酸、イタコン酸、ジグリコール酸、チオジグリコール酸、フタル酸。 Polycarboxylic acids other than the above: oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, oxalic acetic acid, glutaric acid, adipic acid, citraconic acid, itaconic acid, diglycolic acid, thiodiglycolic acid, phthalic acid.
　チオール基を有するカルボン酸：チオグリコール酸、チオサリチル酸。 Carboxylic acid having a thiol group: thioglycolic acid, thiosalicylic acid.
　錯体形成剤は、特に、含窒素複素環基を有するポリカルボン酸もしくはモノカルボン酸、またはシュウ酸などの脂肪族ポリカルボン酸、が好ましく、特に２－ピリジンカルボン酸、２，３－ピリジンカルボン酸が好ましい。２－ピリジンカルボン酸などの含窒素複素環基を有するカルボン酸を用いることにより、特に銅の研磨速度が増大するとともに、研磨パッド上への銅錯体等の付着や残留が防止されるという効果が発揮される。 The complex-forming agent is preferably a polycarboxylic acid or monocarboxylic acid having a nitrogen-containing heterocyclic group, or an aliphatic polycarboxylic acid such as oxalic acid, particularly 2-pyridinecarboxylic acid or 2,3-pyridinecarboxylic acid. Is preferred. By using a carboxylic acid having a nitrogen-containing heterocyclic group such as 2-pyridinecarboxylic acid, the polishing rate of copper is particularly increased, and adhesion and residue of a copper complex or the like on the polishing pad can be prevented. Demonstrated.
　本発明の研磨用組成物中の錯体形成剤の含有量は、研磨用組成物に対して０．１～５質量％、特に０．３～３質量％、さらには０．５～１．５質量％であることが好ましい。０．１質量％未満の場合は、銅の研磨速度が低下するおそれがあり、５質量％超では、銅表面の腐食やディッシングが発生するおそれがある。 The content of the complex-forming agent in the polishing composition of the present invention is 0.1 to 5% by mass, particularly 0.3 to 3% by mass, more preferably 0.5 to 1.5% by mass with respect to the polishing composition. It is preferable that it is mass%. If the amount is less than 0.1% by mass, the polishing rate of copper may decrease, and if it exceeds 5% by mass, corrosion or dishing of the copper surface may occur.
　＜脂環族樹脂酸＞
　本研磨用組成物は、脂環族樹脂酸を含んでいることが好ましい。樹脂酸とは天然樹脂中に遊離またはエステルとして存在する有機酸（カルボン酸）であり、脂環族樹脂酸とはその樹脂酸のうち脂環構造を有する化合物をいう（共立出版（株）発行「化学大辞典４」の「樹脂酸」の項参照）。本発明における脂環族樹脂酸としては、脂環族樹脂酸を含有する天然樹脂、天然樹脂から精製（同時に異性化等が起こることもある）された脂環族樹脂酸を主成分とする精製樹脂酸、天然樹脂から抽出された単一化合物である脂環族樹脂酸やその２種以上の混合物、などがある。 <Alicyclic resin acid>
The polishing composition preferably contains an alicyclic resin acid. Resin acid is an organic acid (carboxylic acid) that is present as a free or ester in natural resin, and alicyclic resin acid is a compound having an alicyclic structure among the resin acids (published by Kyoritsu Shuppan Co., Ltd.) (See “Resin acid” in Chemical Dictionary 4). As the alicyclic resin acid in the present invention, a natural resin containing an alicyclic resin acid, a refined product mainly composed of an alicyclic resin acid purified from a natural resin (at the same time, isomerization or the like may occur). Examples thereof include resin acids, alicyclic resin acids which are single compounds extracted from natural resins, and mixtures of two or more thereof.
　上記精製樹脂酸としては、松脂などから得られるロジン、トール油、トール油ロジンなどがある。特に、ロジンと呼ばれる、アビエチン酸やその異性体、ピマル酸やその異性体、水素化アビエチン酸などの脂環族樹脂酸を主成分とする精製樹脂酸が好ましく、本発明における脂環族樹脂酸として市販のロジンを使用できる。また、ロジンは、それが由来する天然樹脂の種類により含有される化合物やその組成割合が変化するものであるが、脂環族樹脂酸を主成分とするものであればいずれの種類のロジンも使用できる。 Examples of the purified resin acid include rosin obtained from pine resin, tall oil, tall oil rosin and the like. In particular, a purified resin acid mainly composed of an alicyclic resin acid such as rosin, abietic acid or its isomer, pimaric acid or its isomer, or hydrogenated abietic acid is preferable. A commercially available rosin can be used. In addition, rosin is a compound whose composition ratio varies depending on the type of natural resin from which it is derived, but any type of rosin can be used as long as it has an alicyclic resin acid as a main component. Can be used.
　市販のロジンには少量の脂肪族樹脂酸が含まれているものがある。この脂肪族樹脂酸は主にオレイン酸やリノール酸などの不飽和高級脂肪酸であり、その含有量はロジン全体に対して通常１０質量％程度である。 Some commercially available rosins contain a small amount of aliphatic resin acid. The aliphatic resin acid is mainly an unsaturated higher fatty acid such as oleic acid or linoleic acid, and its content is usually about 10% by mass relative to the whole rosin.
　単一化合物である脂環族樹脂酸としては、アビエチン酸、アビエチン酸の異性体であるネオアビエチン酸、パラストリン酸、レボピマル酸など、アビエチン酸の水素化物であるジヒドロアビエチン酸やテトラヒドロアビエチン酸、アビエチン酸の脱水素化物であるデヒドロアビエチン酸、セコデヒドロアビエチン酸などがある。その他、ピマル酸、イソピマル酸、サンダラコピマル酸、コムン酸、ジヒドロアガチン酸などがある。 Examples of alicyclic resin acids that are single compounds include abietic acid, isomers of abietic acid, neoabietic acid, parastrinic acid, levopimaric acid, and the like. There are dehydroabietic acid and secodehydroabietic acid which are dehydrogenated products of acids. In addition, there are pimaric acid, isopimaric acid, sandaracopimaric acid, combonic acid, dihydroagatinic acid and the like.
　研磨用組成物において、上記脂環族樹脂酸は２種以上含有されていてもよい。ロジンなどの精製樹脂酸は本来２種以上の脂環族樹脂酸（単一化合物）の混合物であるが本発明では１種の脂環族樹脂酸とみなす。したがって、研磨用組成物においては、２種以上のロジンが含有されていてもよく、ロジンと単一化合物である脂環族樹脂酸の１種以上が含有されていてもよい。 In the polishing composition, two or more alicyclic resin acids may be contained. A purified resin acid such as rosin is originally a mixture of two or more alicyclic resin acids (single compound), but is regarded as one alicyclic resin acid in the present invention. Therefore, in the polishing composition, two or more kinds of rosins may be contained, or one or more kinds of alicyclic resin acids which are a single compound with rosin may be contained.
　また、脂環族樹脂酸としては、上記精製樹脂酸や単一化合物である脂環族樹脂酸の誘導体であって、少なくとも１個のカルボキシ基を有する化合物やそれを含む混合物、であってもよい。誘導体としては、天然樹脂から抽出される脂環族樹脂酸以外の、異性化物、水素化物、脱水素化物、多量化物、脂環族樹脂酸の不飽和基に不飽和化合物（たとえば無水マレイン酸、フマル酸やアクリル酸などの不飽和カルボン酸（またはその無水物）などをジールスアルダー付加して得られる変性物、などがある。無水マレイン酸付加物（マレイン酸変性物）、フマル酸付加物（フマル酸変性物）、および脱水素化物からなる群から選ばれる１種類以上が好ましい。上記の脱水素化物としては、脱水素により脂環の一部が芳香環となったものも含まれる。 The alicyclic resin acid may be a derivative of the above-described purified resin acid or a single compound alicyclic resin acid, which is a compound having at least one carboxy group or a mixture containing the same. Good. Examples of the derivatives include isomerized products, hydrides, dehydrogenated products, multimerized products, unsaturated compounds (eg, maleic anhydride, alicyclic resin acids) other than alicyclic resin acids extracted from natural resins. There are modified products obtained by Diels-Alder addition of unsaturated carboxylic acids such as fumaric acid and acrylic acid (or their anhydrides), etc. Maleic anhydride adduct (maleic acid modified product), fumaric acid adduct (Fumaric acid-modified product) and at least one selected from the group consisting of dehydrogenated products are preferable, and the dehydrogenated product includes those in which a part of the alicyclic ring is converted to an aromatic ring by dehydrogenation.
　また、アビエチン酸（アビエチン酸の異性体であるネオアビエチン酸、アビエチン酸の水素化物であるジヒドロアビエチン酸やテトラヒドロアビエチン酸、アビエチン酸の脱水素化物などを含む）の含有量は、０．５～２．５質量％、さらには０．１５～１．５質量％であることが、効果的に銅の表面を保護できるため好ましい。また、ドデシルベンゼンスルホン酸と脂環族樹脂酸との含有量比（質量比）は、効果的に研磨用組成物を濃縮できる点で、４：１～１：４、特に３：１～１：３であることが好ましい。 The content of abietic acid (including neoabietic acid which is an isomer of abietic acid, dihydroabietic acid which is a hydride of abietic acid, tetrahydroabietic acid, dehydrogenated product of abietic acid, etc.) is 0.5 to The content of 2.5% by mass, and further 0.15 to 1.5% by mass is preferable because the copper surface can be effectively protected. The content ratio (mass ratio) of dodecylbenzenesulfonic acid and alicyclic resin acid is 4: 1 to 1: 4, particularly 3: 1 to 1 in that the polishing composition can be concentrated effectively. : 3 is preferable.
　脂環族樹脂酸には、脂環族樹脂酸の塩も含む。脂環族樹脂酸の塩としては、ロジンとも呼ばれているロジンのアルカリ金属塩（特にカリウム塩）、ロジンのアンモニウム塩、ロジンの有機アミン塩が好ましい。また単一化合物である脂環族樹脂酸の塩としては、たとえば以下のような塩があり、これらの２種以上の混合物も使用できる。アビエチン酸カリウム塩、デヒドロアビエチン酸カリウム塩、テトラヒドロアビエチン酸カリウム塩、ジヒドロアビエチン酸カリウム塩、ピマル酸カリウム塩、アビエチン酸アンモニウム塩、デヒドロアビエチン酸アンモニウム塩、テトラヒドロアビエチン酸アンモニウム塩、ジヒドロアビエチン酸アンモニウム塩、ピマル酸アンモニウム塩、アビエチン酸有機アミン塩、デヒドロアビエチン酸有機アミン塩、テトラヒドロアビエチン酸有機アミン塩、ジヒドロアビエチン酸有機アミン塩、ピマル酸有機アミン塩。 Alicyclic resin acids include salts of alicyclic resin acids. As the alicyclic resin acid salt, rosin alkali metal salt (particularly potassium salt), rosin ammonium salt, and rosin organic amine salt, also called rosin, are preferable. Moreover, as a salt of the alicyclic resin acid which is a single compound, there exist the following salts, for example, These 2 or more types of mixtures can also be used. Abietic acid potassium salt, dehydroabietic acid potassium salt, tetrahydroabietic acid potassium salt, dihydroabietic acid potassium salt, pimaric acid potassium salt, abietic acid ammonium salt, dehydroabietic acid ammonium salt, tetrahydroabietic acid ammonium salt, dihydroabietic acid ammonium salt , Ammonium pimarate, organic amine salt of abietic acid, organic amine salt of dehydroabietic acid, organic amine salt of tetrahydroabietic acid, organic amine salt of dihydroabietic acid, organic amine salt of pimaric acid.
　研磨用組成物では、脂環族脂肪酸を含有させることによりディッシング量を抑制する効果が得られる。このような効果が得られる機構は明らかでないが、研磨時に、半導体集積回路銅膜の表面と何らかの化学的作用または物理的作用をおこなって銅膜表面に保護層を形成する表面保護剤として作用していると考えられる。この表面保護層は、銅膜の研磨を完全に阻害するほど強固ではなく、半導体集積回路基板上の銅膜において、研磨パッドの押付け圧が大きい凸部においては研磨が進行し、押付け圧が小さい配線部分の凹部においては研磨が進行しない。それにより高平滑な研磨表面性状が実現されると考えられる。 In the polishing composition, an effect of suppressing the amount of dishing can be obtained by including an alicyclic fatty acid. Although the mechanism for obtaining such an effect is not clear, it acts as a surface protective agent that forms a protective layer on the surface of the copper film by performing some chemical or physical action on the surface of the semiconductor integrated circuit copper film during polishing. It is thought that. This surface protective layer is not so strong as to completely hinder the polishing of the copper film, and in the copper film on the semiconductor integrated circuit substrate, the polishing progresses at the convex portion where the pressing pressure of the polishing pad is large, and the pressing pressure is small. Polishing does not proceed in the concave portion of the wiring portion. Thereby, it is considered that a highly smooth polished surface property is realized.
　研磨用組成物中の脂環族樹脂酸の含有量は０．１～５質量％、さらには０．３～３質量％、０．３質量％～２質量％、０．３質量％～１質量％であることが好ましい。０．０１質量％未満の場合は銅膜表面の保護作用が不十分であると考えられ、研磨中に腐食及びディッシングが発生し易くなる。また、２質量％超では銅の研磨速度が低下する恐れがある。 The content of the alicyclic resin acid in the polishing composition is 0.1 to 5% by mass, further 0.3 to 3% by mass, 0.3% to 2% by mass, 0.3% to 1% by mass. It is preferable that it is mass%. If it is less than 0.01% by mass, it is considered that the protective action of the copper film surface is insufficient, and corrosion and dishing are likely to occur during polishing. On the other hand, if it exceeds 2% by mass, the polishing rate of copper may decrease.
　また、錯体形成剤と脂環族樹脂酸との含有量比（質量比）は、研磨速度を良好とできる点で５０：１～３０：１、特に４５：１～３５：１であることが好ましい。 In addition, the content ratio (mass ratio) of the complex-forming agent and the alicyclic resin acid is 50: 1 to 30: 1, particularly 45: 1 to 35: 1 in that the polishing rate can be improved. preferable.
　＜酸化剤＞
　酸化剤は、その機構は定かではないが、銅などの金属を酸化し金属イオン又は酸化物を生成する役割を演じる。酸化剤による反応で生成した銅イオンと錯体形成剤とが錯体を形成することで、研磨が進行すると考えられる。 <Oxidizing agent>
Although the mechanism of the oxidizing agent is not clear, it plays a role of oxidizing a metal such as copper to form a metal ion or oxide. It is considered that the polishing proceeds when the copper ions generated by the reaction with the oxidizing agent and the complex forming agent form a complex.
　酸化剤としては、熱や光等の外部エネルギーによって酸素－酸素結合が解離しラジカルを生成する酸素－酸素結合を持つ過酸化物が、強い酸化力を示すので好ましい。このような過酸化物系酸化剤の例としては、過酸化水素、過硫酸塩類、ペルオキソ炭酸塩類、ペルオキソ硫酸塩類、ペルオキソリン酸塩類等の無機過酸化物や、過酸化ベンゾイル、ｔ－ブチルヒドロペルオキシド、クメンヒドロペルオキシド、ジイソプロピルベンゼンヒドロペルオキシド、過蟻酸、過酢酸等の有機過酸化物などがあげられる。好ましい酸化剤は過酸化水素、過硫酸アンモニウム、または過硫酸カリウムである。これらの酸化剤の中では、アンモニウム塩類、特に過硫酸アンモニウムを用いると、銅膜に対して高い研磨速度が得られるのでより好ましい。次いで好ましい酸化剤は過酸化水素と過硫酸カリウムである。 As the oxidizing agent, a peroxide having an oxygen-oxygen bond that generates a radical by dissociation of an oxygen-oxygen bond by external energy such as heat or light is preferable because it exhibits a strong oxidizing power. Examples of such peroxide-based oxidizing agents include inorganic peroxides such as hydrogen peroxide, persulfates, peroxocarbonates, peroxosulfates, peroxophosphates, benzoyl peroxide, t-butylhydro Examples thereof include organic peroxides such as peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, performic acid and peracetic acid. Preferred oxidizing agents are hydrogen peroxide, ammonium persulfate, or potassium persulfate. Among these oxidizing agents, it is more preferable to use ammonium salts, particularly ammonium persulfate, because a high polishing rate can be obtained for the copper film. The preferred oxidizing agents are then hydrogen peroxide and potassium persulfate.
　研磨用組成物に対する酸化剤の含有量は０．１～５質量％、特に０．５～３質量％、０．５～１．５質量％が望ましい。０．１質量％未満では銅の研磨速度が低下するおそれがある。５質量％超では、銅表面の腐食やディッシングが発生しやすくなる。ディッシングを抑制しつつ銅膜を高速で研磨するためには、過硫酸アンモニウム、過酸化水素および過硫酸カリウムから選ばれる少なくとも１種の酸化剤を用いることが好ましい。特に過硫酸アンモニウムを用いることが好ましい。 The content of the oxidizing agent in the polishing composition is preferably 0.1 to 5% by mass, particularly 0.5 to 3% by mass, and 0.5 to 1.5% by mass. If it is less than 0.1% by mass, the copper polishing rate may decrease. If it exceeds 5% by mass, corrosion or dishing of the copper surface tends to occur. In order to polish the copper film at a high speed while suppressing dishing, it is preferable to use at least one oxidizing agent selected from ammonium persulfate, hydrogen peroxide, and potassium persulfate. In particular, it is preferable to use ammonium persulfate.
　＜水＞
　本発明の研磨用組成物における主たる液状媒体は水であり、水のみまたは水と水溶性溶媒との混合物からなることが好ましい。水としては、イオン交換し、異物が除去された純水を用いることが好ましい。水溶性溶媒としては、水溶性アルコール、水溶性ポリオール、水溶性エステル、水溶性エーテルなどを使用できる。本発明の研磨用組成物における液状媒体は水のみまたは水を８０質量％以上含む水と水溶性有機溶媒との混合溶媒が好ましく、実質的に水のみからなることが最も好ましい。また、本発明の研磨用組成物における液状媒体の割合は９０質量％以上、特に９５質量％以上からなることが好ましい。この液状媒体の実質的全量は水からなることが好ましく、その場合本発明の研磨用組成物における水の含有量は、９０質量％以上、特に９５質量％以上であることが好ましい。 <Water>
The main liquid medium in the polishing composition of the present invention is water, and preferably consists of water alone or a mixture of water and a water-soluble solvent. As the water, it is preferable to use pure water which has been subjected to ion exchange and from which foreign substances have been removed. As the water-soluble solvent, water-soluble alcohols, water-soluble polyols, water-soluble esters, water-soluble ethers, and the like can be used. The liquid medium in the polishing composition of the present invention is preferably water alone or a mixed solvent of water containing 80% by mass or more of water and a water-soluble organic solvent, and most preferably consists essentially of water. The proportion of the liquid medium in the polishing composition of the present invention is preferably 90% by mass or more, particularly 95% by mass or more. Substantially the total amount of the liquid medium is preferably composed of water. In that case, the water content in the polishing composition of the present invention is preferably 90% by mass or more, particularly preferably 95% by mass or more.
　前記の本発明の研磨用組成物の各成分の割合は研磨をおこなうときの組成割合をいう。
研磨に先立ち研磨用濃縮組成物を希釈し、その希釈物を研磨に使用する場合、上記および後述の各成分の割合はこの希釈物における割合である。研磨用濃縮組成物は通常液状媒体（特に水）で希釈され、したがって、その場合液状媒体を除く各成分の相対的割合は希釈の前後で通常は変化しない。 The ratio of each component of the polishing composition of the present invention refers to the composition ratio when polishing is performed.
When the polishing composition is diluted prior to polishing and the diluted solution is used for polishing, the ratio of each component described above and below is a ratio in the diluted product. The polishing composition is usually diluted with a liquid medium (especially water), and in this case, the relative proportions of the components other than the liquid medium are usually not changed before and after the dilution.
　本発明の研磨用組成物のｐＨ値は、７．５～１２、特に８～１１、さらには８．５～１０．５であることが好ましい。より好ましくは９～１０である。ｐＨ値が７．５より低いと、本発明の研磨用組成物中に含有させた脂環族樹脂酸が、研磨用組成物中で分離して不均一になるおそれがある。銅を高速に研磨するためには、ｐＨ値を８．０以上とすることが好ましい。ｐＨ値が１２より高いと銅膜の腐蝕が顕著なため好ましくない。銅膜の研磨残りや腐蝕を充分に抑制するためには、ｐＨ値を１１以下とすることが好ましい。 The pH value of the polishing composition of the present invention is preferably 7.5 to 12, particularly 8 to 11, and more preferably 8.5 to 10.5. More preferably, it is 9-10. When the pH value is lower than 7.5, the alicyclic resin acid contained in the polishing composition of the present invention may be separated in the polishing composition and become non-uniform. In order to polish copper at high speed, the pH value is preferably 8.0 or more. A pH value higher than 12 is not preferable because corrosion of the copper film is remarkable. In order to sufficiently suppress polishing residue and corrosion of the copper film, the pH value is preferably 11 or less.
　本発明の研磨用組成物を、上述のｐＨ値に調整するためにはｐＨ調整剤を用いることができる。塩基性側へ調整する場合は、水酸化カリウム、有機アミン、アンモニアを用いることが好ましい。これらのいずれを用いてもよいが、銅と錯イオンを形成する有機アミンやアンモニアを用いると、銅膜に対して大きな研磨速度が得られて好ましい。また、ｐＨ調整は、いったん所望のｐＨ値より塩基性側とした後、硝酸、硫酸、リン酸などを添加して酸性側へ調整して所望のｐＨ値に調整してもよい。 In order to adjust the polishing composition of the present invention to the above pH value, a pH adjuster can be used. When adjusting to the basic side, it is preferable to use potassium hydroxide, organic amine, or ammonia. Any of these may be used, but it is preferable to use an organic amine or ammonia that forms a complex ion with copper because a large polishing rate can be obtained with respect to the copper film. In addition, the pH may be adjusted to a desired pH value by adjusting the pH to the acidic side by adding nitric acid, sulfuric acid, phosphoric acid, etc. once the basic pH is set to the desired pH value.
　本発明の研磨用組成物を調製する一連の工程の中で、ｐＨ調整剤を混合する工程の順番は問わないが、あらかじめ塩とすることなく脂環族樹脂酸などを含有させるときには、液状媒体にｐＨ調整剤を混合して塩基性とした液状媒体（他の成分の一部ないし全部が既に含有されていてもよい）にしておくと、脂環族樹脂酸などの溶解～混合が容易になるとともに、分離しにくくなるため好ましい。 In the series of steps for preparing the polishing composition of the present invention, the order of the step of mixing the pH adjuster is not limited. However, when the alicyclic resin acid or the like is contained in advance without forming a salt, a liquid medium is used. When a liquid medium made basic by mixing with a pH adjuster (some or all of other components may already be contained) is prepared, dissolution and mixing of the alicyclic resin acid and the like are facilitated. It is preferable because it becomes difficult to separate.
　＜砥粒＞
　本発明の研磨用組成物は、砥粒を配合しない場合にもその効果を発揮し得るが、砥粒を配合して用いてもよく、その場合、さらに銅を高速に研磨することができる。 <Abrasive>
The polishing composition of the present invention can exert its effect even when no abrasive grains are blended. However, the abrasive composition may be blended and used, and in that case, copper can be further polished at a high speed.
　本発明の研磨用組成物に配合することができる砥粒としては、α－アルミナ、δ－アルミナ、γ－アルミナ、シリカ、セリアなどがあげられる。が、その中でも、シリカを用いることが好ましい。シリカを用いる場合には、分散性、安定性、研磨力などの点からコロイダルシリカを用いることがより好ましい。 Examples of abrasive grains that can be blended in the polishing composition of the present invention include α-alumina, δ-alumina, γ-alumina, silica, and ceria. However, among these, it is preferable to use silica. When silica is used, colloidal silica is more preferably used from the viewpoints of dispersibility, stability, polishing power, and the like.
　砥粒を配合する場合、平均２次粒子径で１０～２００ｎｍが好ましい。平均２次粒子径２００ｎｍ超では、砥粒径が大きすぎて砥粒の濃度を大きくすることが困難となり、１０ｎｍ未満では、研磨速度の向上が困難となる。好ましくは２０～１２０ｎｍの範囲である。
　本発明の研磨用組成物に対する砥粒の含有量は０．０１～１０質量％、特に０．０５～５質量％、さらには０．０５～２質量％、０．０５～１質量％、０．０５～０．６質量％が好ましい。 When blending abrasive grains, the average secondary particle diameter is preferably 10 to 200 nm. If the average secondary particle diameter exceeds 200 nm, it is difficult to increase the concentration of the abrasive grains because the abrasive particle diameter is too large, and if it is less than 10 nm, it is difficult to improve the polishing rate. The range of 20 to 120 nm is preferable.
The content of the abrasive grains in the polishing composition of the present invention is 0.01 to 10% by mass, particularly 0.05 to 5% by mass, further 0.05 to 2% by mass, 0.05 to 1% by mass, 0%. 0.05 to 0.6% by mass is preferable.
　＜防錆剤＞
　本研磨用組成物は、防錆剤を含むことが好ましい。防錆剤としては、具体的には、イミダゾール誘導体であることが、特にピットを防止できる点で好ましい。イミダゾール誘導体とは、具体的には、イミダゾールおよび、イミダゾールについて、下式に示す１～５位がメチル基で置換されていてもよく、４，５位は、置換基が付いていてもよいベンゼン環の一部となっていてもよい、誘導体である。 <Rust preventive>
The polishing composition preferably contains a rust inhibitor. Specifically, the rust inhibitor is preferably an imidazole derivative, particularly in terms of preventing pits. The imidazole derivative specifically refers to imidazole and benzene in which 1 to 5 positions shown in the following formula may be substituted with a methyl group, and the 4 and 5 positions may be benzene which may have a substituent. A derivative that may be part of a ring.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　イミダゾール誘導体としては、具体的には、ベンズイミダゾール、イミダゾール、１－メチルイミダゾール、２－メチルイミダゾール、４－メチルイミダゾール、１,２－ジメチルイミダゾール、２－エチルイミダゾール等が挙げられる。これらは単独で使用してもよく、２種以上を混合して使用してもよい。イミダゾール誘導体は、研磨特性の点から研磨用組成物の全質量に対し、０．００１～０．５％含まれることが好ましく、０．００３～０．３％含まれることがより好ましい。 Specific examples of the imidazole derivative include benzimidazole, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, and the like. These may be used alone or in combination of two or more. The imidazole derivative is preferably contained in an amount of 0.001 to 0.5%, more preferably 0.003 to 0.3% based on the total mass of the polishing composition in terms of polishing characteristics.
　＜その他の成分＞
　本発明の研磨方法に用いられる研磨用組成物には、本発明の趣旨に反しない限り、上記の成分の他に還元剤、粘度調整剤、分散剤、防腐剤等を適宜配合することもできる。ただし、これらの含有量は、通常合計で１０質量％以下、特に５質量％以下、３質量％以下であることが好ましい。 <Other ingredients>
In the polishing composition used in the polishing method of the present invention, a reducing agent, a viscosity modifier, a dispersing agent, a preservative, and the like can be appropriately blended in addition to the above-described components as long as the gist of the present invention is not violated. . However, these contents are generally 10% by mass or less, and particularly preferably 5% by mass or less and 3% by mass or less in total.
　このようにして構成された研磨用組成物は、銅を配線用金属として用いた場合に銅残りやピットを抑制でき、精度の高い表面平坦化を実現できる。このため、優れて平坦な表面状態を有する半導体集積回路表面を得ることができ、半導体集積回路の多層化、細線化にとって極めて有効である。 The polishing composition thus configured can suppress copper residue and pits when copper is used as a wiring metal, and can realize highly accurate surface flattening. Therefore, it is possible to obtain a semiconductor integrated circuit surface having an excellent flat surface state, which is extremely effective for multilayering and thinning of the semiconductor integrated circuit.
　本発明にかかる研磨用組成物は、研磨剤として、配線用の溝を持つ表面に形成された銅膜を研磨するのに適する。本発明にかかる研磨用組成物にさらにその他の構成成分を加えて研磨剤として使用してもよい。より具体的には、ダマシン法により銅配線を形成する半導体集積回路装置の製造方法においてディッシングやエロージョンの進行が効果的に抑制されるので、優れて平坦な表面状態を有する半導体集積回路表面を得ることができる。 The polishing composition according to the present invention is suitable for polishing a copper film formed on a surface having a groove for wiring as an abrasive. Other constituent components may be added to the polishing composition according to the present invention and used as an abrasive. More specifically, since the progress of dishing and erosion is effectively suppressed in the method of manufacturing a semiconductor integrated circuit device in which copper wiring is formed by the damascene method, a semiconductor integrated circuit surface having an excellent flat surface state is obtained. be able to.
　　＜研磨用組成物＞
　本発明に係る研磨用組成物は、ドデシルベンゼンスルホン酸成分を必須とし、アルケニルコハク酸成分、ポリオキシエチレンアルキルエーテルカルボン酸成分およびポリオキシエチレンアルキルエーテルリン酸成分からなる群から選ばれた少なくとも一つの平坦性向上剤を含む。上記のような組成とすることで、絶縁層上にバリア層を介して設けられた銅層を研磨して、幅１００μｍの銅埋込み配線と幅１００μｍの絶縁層とを交互に形成するパターン形成において、銅層に隣接したバリア層が露出した後に、当該バリア層が露出する前の銅の研磨速度で当該銅を２００ｎｍ研磨するのに要する時間だけ研磨したときのディッシング量（センターチップでもエッジチップでも）が５５ｎｍ以下、特に４５ｎｍ以下である特徴を有するようになすことが可能である。これにより、銅を配線用金属として用いた場合に精度の高い表面平坦化を実現できる。 <Polishing composition>
The polishing composition according to the present invention essentially contains a dodecylbenzenesulfonic acid component, and is at least one selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component, and a polyoxyethylene alkyl ether phosphoric acid component. Contains two flatness improvers. In the pattern formation in which the copper layer provided on the insulating layer through the barrier layer is polished by the above composition to form the copper embedded wiring having a width of 100 μm and the insulating layer having a width of 100 μm alternately. After the barrier layer adjacent to the copper layer is exposed, the amount of dishing when the copper is polished for 200 nm at the polishing rate of copper before the barrier layer is exposed (center chip or edge chip) ) Is 55 nm or less, particularly 45 nm or less. Thereby, when copper is used as a metal for wiring, highly accurate surface flattening can be realized.
　研磨条件には、研磨速度、研磨パッドの押し付け圧等の可変条件があるが、これらについては特に制限はない。一般的には、好ましくは研磨速度を２００～８００ｎｍ／分とし、研磨パッドの押し付け圧を４ｐｓｉ（換算値は２７．６ｋＰａ）以下とすることが好ましい。 Polishing conditions include variable conditions such as polishing speed and pressing pressure of the polishing pad, but there are no particular restrictions on these conditions. In general, the polishing rate is preferably 200 to 800 nm / min, and the pressing pressure of the polishing pad is preferably 4 psi (converted value is 27.6 kPa) or less.
　上記において、ディッシング量は、後述するように、図４（ｂ）の符号７で表される深さである（または図５の符号１７で表される深さである）。 In the above, the dishing amount is a depth represented by reference numeral 7 in FIG. 4B (or a depth represented by reference numeral 17 in FIG. 5), as will be described later.
　＜研磨方法＞
　本発明に係る研磨用組成物は、絶縁層上にバリア層を介して設けられた銅層を研磨して、銅埋込み配線と絶縁層とを交互に形成するパターン形成のための研磨方法であって、上記の研磨用組成物である第１の研磨用組成物で研磨する第１研磨工程と、その後、絶縁層上にバリア層を介して設けられた銅層を研磨して、銅埋込み配線と絶縁層とを交互に形成するパターン形成において、第２の研磨用組成物で研磨する第２研磨工程と、を備えた研磨方法に好ましく使用することができる。 <Polishing method>
The polishing composition according to the present invention is a polishing method for pattern formation in which a copper layer provided on an insulating layer via a barrier layer is polished to alternately form copper embedded wiring and insulating layers. A first polishing step of polishing with the first polishing composition as the polishing composition, and then polishing a copper layer provided on the insulating layer via a barrier layer, thereby In the pattern formation in which the insulating layer and the insulating layer are alternately formed, the second polishing step of polishing with the second polishing composition can be preferably used.
　これらの二種類の研磨用組成物を使い分ける本研磨方法により、銅を配線用金属として用いた場合に、ディッシングやエロージョンの少ない、優れて平坦な表面を、面内均一性よく実現できる。このため、半導体集積回路の多層化、細線化にとって極めて有効である。 The present polishing method that selectively uses these two types of polishing compositions can realize an excellent flat surface with less dishing and erosion and good in-plane uniformity when copper is used as a wiring metal. For this reason, it is extremely effective for multilayering and thinning of semiconductor integrated circuits.
　上記第１研磨工程と第２研磨工程とは、第１研磨工程の直後に第２研磨工程を行い、それで研磨を完成するのが一般的に好ましいが、必要に応じて第１研磨工程と第２研磨工程の間、第１研磨工程の前や第２研磨工程の後に他の工程を含めてもよい。第１研磨工程の終了時期、第２研磨工程の開始時期および終了時期については特に制限はなく、研磨の実情に応じて適宜定めることができるが、通常は、絶縁層上にバリア層を介して設けられた銅層が、配線以外において除去された時点で第１研磨工程を止めて第２研磨工程に移り、所定の表面平坦性が得られた時点で第２研磨工程を止めることが好ましい。すなわち、第１研磨工程で銅配線以外の銅の部分を除去し、第２研磨工程でバリア層を除去すると共に、たいていの場合には絶縁層と、必要であれば銅の一部を極くわずかに研磨して、絶縁層と銅層とからなる平坦な面が形成される。 In the first polishing step and the second polishing step, it is generally preferable to perform the second polishing step immediately after the first polishing step to complete the polishing, but the first polishing step and the second polishing step are performed as necessary. During the two polishing steps, other steps may be included before the first polishing step or after the second polishing step. There are no particular restrictions on the end time of the first polishing step and the start time and end time of the second polishing step, which can be appropriately determined according to the actual situation of polishing, but usually, a barrier layer is interposed on the insulating layer. It is preferable that when the provided copper layer is removed except for the wiring, the first polishing process is stopped and the process proceeds to the second polishing process, and when the predetermined surface flatness is obtained, the second polishing process is stopped. That is, the copper portion other than the copper wiring is removed in the first polishing step, the barrier layer is removed in the second polishing step, and in most cases, the insulating layer and, if necessary, a part of the copper are extremely used. By polishing slightly, a flat surface composed of an insulating layer and a copper layer is formed.
　以下に本発明を実施例を用いて説明するが、本発明は以下の記載に限定されない。例１～６４および８６～１１１は実施例、例６５～８５は比較例である。 Hereinafter, the present invention will be described using examples, but the present invention is not limited to the following description. Examples 1 to 64 and 86 to 111 are examples, and examples 65 to 85 are comparative examples.
　例１～１１１の各例の研磨用組成物の組成は、表１～６にまとめた通りである。それぞれの成分の含有量は、混合された研磨用組成物全体に対する質量％で記した。ｐＨ値は、横河電機社製のｐＨメーター　ｐＨ８１－１１で測定した。また、コロイダルシリカの平均２次粒子径は、NIKKISO社製のマイクロトラックUPA-ST150粒度分析計を使い、動的光散乱法で測定した。測定サンプルは、測定に適正な散乱、反射光強度が得られる、装置の定める適正濃度範囲に純水で希釈して測定を行った。 The compositions of the polishing compositions in Examples 1 to 111 are as summarized in Tables 1 to 6. Content of each component was described by the mass% with respect to the whole polishing composition mixed. The pH value was measured with a pH meter pH81-11 manufactured by Yokogawa Electric Corporation. The average secondary particle size of colloidal silica was measured by a dynamic light scattering method using a Microtrac UPA-ST150 particle size analyzer manufactured by NIKKISO. The measurement sample was measured by diluting with pure water in an appropriate concentration range determined by the apparatus, which can obtain appropriate scattering and reflected light intensity for measurement.
　研磨用組成物は、例１については、錯体形成剤である２－ピリジンカルボン酸の所定量をイオン交換水に添加し、次いで、表２に記載されているようなｐＨとなるように、ｐＨ調整剤である水酸化カリウムを添加し、充分に撹拌した。さらに撹拌しながら、脂環族樹脂酸であるＫＲ６１４（荒川化学工業社製）、溶解助剤のドデシルベンゼンスルホン酸、平坦性向上剤のアルケニルコハク酸、および酸化剤であるＡＰＳ（過硫酸アンモニウム）を添加し、次いで砥粒であるコロイダルシリカを添加して作製した。例１以外の他の例についても、表１～６に記載されたような組成で、例１と同様に処理して研磨用組成物を得た。 The polishing composition for Example 1 was prepared by adding a predetermined amount of 2-pyridinecarboxylic acid, which is a complex-forming agent, to ion-exchanged water, and then adjusting the pH so that the pH was as described in Table 2. Potassium hydroxide as a regulator was added and stirred thoroughly. Further, with stirring, KR614 (produced by Arakawa Chemical Industries) as an alicyclic resin acid, dodecylbenzenesulfonic acid as a dissolution aid, alkenyl succinic acid as a flatness improving agent, and APS (ammonium persulfate) as an oxidizing agent. Then, colloidal silica as an abrasive was added to prepare. Other examples other than Example 1 were processed in the same manner as in Example 1 with the compositions as shown in Tables 1 to 6 to obtain polishing compositions.
　使用したＫＲ６１４に関し、ＧＣ／ＭＳ法により複数ロットについて、以下のとおり分析を行った。 Regarding KR614 used, the following analysis was performed for multiple lots by the GC / MS method.
　分析はＰＴＡＨ法によりガスクロマトグラフィを用いておこなった。すなわち、分析する各試料６ミリグラムをＰＴＡＨ（ジーエルサイエンス社製、Ｐｈｅｎｙｌ　Ｔｒｉｍｅｔｈｙｌ　Ａｍｍｏｎｉｕｍ　Ｈｙｄｒｏｘｉｄｅ　０．２モルメタノール溶液）０．５ミリリットルに溶解し、インジェクション温度を２５０℃としたガスクロマトグラフィ装置に注入し、瞬間的にメチルエステル化して測定した。カラムは、ＤＥＧＳ（Diethylene glycol succinate）を充填した、内径０．２５ｍｍ、長さ２５ｍ、膜厚０．２５μｍのキャピラリーカラムを用いて、オーブン温度は１８０度、試料の注入量は４．０μリットルとした。ディテクターにはＦＩＤを用いて、得られた測定チャート上のピーク面積から各成分の含有量を求めた。上記のＧＣ／ＭＳ法による複数ロットの分析の結果、ＫＲ６１４は、主成分としてデヒドロアビエチン酸を７５～８５質量％含有していることが分かった。オレイン酸のピークは検出されなかった。 Analysis was performed using gas chromatography by the PTAH method. That is, 6 milligrams of each sample to be analyzed was dissolved in 0.5 ml of PTAH (Phenyl Trimethyl Ammonium Hydroxide 0.2 M methanol solution, manufactured by GL Sciences Inc.) and injected into a gas chromatography apparatus with an injection temperature of 250 ° C. The measurement was carried out after methyl esterification. The column used was a capillary column packed with DEGS (Diethylene glycol succinate) with an inner diameter of 0.25 mm, a length of 25 m, and a film thickness of 0.25 μm. The oven temperature was 180 ° C. and the sample injection amount was 4.0 μl. . Using FID as a detector, the content of each component was determined from the peak area on the obtained measurement chart. As a result of analysis of a plurality of lots by the above GC / MS method, it was found that KR614 contains 75 to 85% by mass of dehydroabietic acid as a main component. No oleic acid peak was detected.
　研磨用組成物の研磨特性は下記の方法により評価した。 The polishing characteristics of the polishing composition were evaluated by the following methods.
　＜被研磨物＞
　被研磨物として、ブランケットウエハとパターン付きウェハとを使用した。 <Polished object>
A blanket wafer and a patterned wafer were used as the objects to be polished.
　ブランケットウエハとしては、銅研磨速度評価用には、Ｓｉ基板上に厚さ１５００ｎｍの銅膜を湿式メッキで成膜した８インチウェハ（Ｓｅｍａｔｅｃｈ社製０００ＣＵＲ０１５）を使用した。 As the blanket wafer, an 8-inch wafer (000 CUR015 manufactured by Sematech Co., Ltd.) in which a 1500 nm thick copper film was formed on the Si substrate by wet plating was used for copper polishing rate evaluation.
　パターン付きウェハとしてはＳｅｍａｔｅｃｈ社製８インチウェハ（商品名：８５４ＣＭＰ２２５）を使用した。研磨前のパターン付きウェハの概略断面を図４（ａ）に示す。
このパターン付きウェハは、Ｓｉ基板１上に形成された埋め込み配線が埋め込まれる凹部と凸部とが形成されたＳｉＯ２よりなる絶縁層２上に、スパッタリングにより成膜された厚さ２５ｎｍのタンタル膜からなるバリア層３と、さらにその上に、湿式メッキで成膜された所定の膜厚の銅膜からなる配線金属層４とが積層され、配線幅が１００μｍから１８０ｎｍの様々な幅の配線パターンが形成されている。絶縁層２の凸部上のタンタル膜からなるバリア層３の表面上の銅膜の膜厚が初期膜厚８であって、絶縁層２の凸部上と凹部上に形成された銅膜の段差が初期段差９である。初期膜厚は９００ｎｍ、初期段差は３５０ｎｍであった。 An 8-inch wafer (trade name: 854CMP225) manufactured by Sematech was used as the wafer with a pattern. A schematic cross section of the patterned wafer before polishing is shown in FIG.
This patterned wafer is a 25-nm-thick tantalum film formed by sputtering on an insulating layer 2 made of SiO 2 in which concave and convex portions in which embedded wirings formed on the Si substrate 1 are embedded are formed. And a wiring metal layer 4 made of a copper film having a predetermined film thickness formed by wet plating, and a wiring pattern having a wiring width of 100 μm to 180 nm. Is formed. The film thickness of the copper film on the surface of the barrier layer 3 made of the tantalum film on the convex portion of the insulating layer 2 is the initial film thickness 8, and the copper film formed on the convex portion and the concave portion of the insulating layer 2 The step is the initial step 9. The initial film thickness was 900 nm and the initial step was 350 nm.
　＜研磨特性の評価＞
　研磨機としては、ＡＰＰＬＩＥＤ　ＭＡＴＥＲＩＡＬＳ社製全自動ＣＭＰ装置　ＭＩＲＲＡを使用した。研磨パッドとしては、２層パッドＩＣ１４００のＸＹＫ－ｇｒｏｏｖｅ（ニッタハース社製）を使用し、ＭＥＣ１００－ＰＨ３．５Ｌ（三菱マテリアル社製）を用いてコンディショニングをおこなった。 <Evaluation of polishing characteristics>
As the polishing machine, a fully automatic CMP apparatus MIRRA manufactured by APPLIED MATERIALS was used. As a polishing pad, XYK-groove (manufactured by Nitta Haas) having a two-layer pad IC1400 was used, and conditioning was performed using MEC100-PH3.5L (manufactured by Mitsubishi Materials Corporation).
　研磨は、例１の研磨用組成物については、研磨用組成物の供給速度を２００ｍｌ／分、研磨ヘッド（Ｈｅａｄ）および研磨定盤（Ｐｌａｔｅｎ）の回転数をそれぞれ１２３ｒｐｍ、１１７ｒｐｍとし、研磨圧を２ｐｓｉすなわち１３．８ｋＰａとしておこなった。 For the polishing composition of Example 1, the polishing composition was supplied at a rate of 200 ml / min, the rotation speed of the polishing head (Head) and the polishing platen (Platen) was 123 rpm and 117 rpm, respectively, and the polishing pressure was Performed at 2 psi or 13.8 kPa.
　また、例２以降については、研磨用組成物の供給速度を２００ｍｌ／分、研磨ヘッド（Ｈｅａｄ）および研磨定盤（Ｐｌａｔｅｎ）の回転数をそれぞれ１２３ｒｐｍ、１１７ｒｐｍとした。研磨圧は、例４～３０，３３，３４，４７～４９，５７～６３，９０，９４，９５，９８～１００，１０２～１０９については１．５ｐｓｉすなわち１０．４ｋＰａとし、その他の例については２ｐｓｉすなわち１３．８ｋＰａとしておこなった。 In Examples 2 and later, the supply rate of the polishing composition was 200 ml / min, and the rotation speeds of the polishing head (Head) and the polishing platen (Platen) were 123 rpm and 117 rpm, respectively. The polishing pressure is 1.5 psi for Examples 4 to 30, 33, 34, 47 to 49, 57 to 63, 90, 94, 95, 98 to 100, 102 to 109, or 10.4 kPa. Performed at 2 psi or 13.8 kPa.
　（１）ベタ研磨速度
　ブランケットウエハを用いた銅研磨速度の測定は、膜厚計ＲＳ－７５（ＫＬＡ－Ｔｅｎｃｏｒ社製）を使用しておこなった。すなわち、銅のブランケットウエハについて、研磨前の膜厚と１分間研磨した後の膜厚とを測定し、その差からそれぞれ銅研磨速度（ｎｍ／分）を求めた。Ｃｕの研磨速度は、７００ｎｍ以上であることが好ましい。 (1) Solid polishing rate The copper polishing rate using a blanket wafer was measured using a film thickness meter RS-75 (manufactured by KLA-Tencor). That is, for the copper blanket wafer, the film thickness before polishing and the film thickness after polishing for 1 minute were measured, and the copper polishing rate (nm / min) was obtained from the difference. The polishing rate of Cu is preferably 700 nm or more.
　研磨用組成物の研磨で使用したパターン付きウェハの研磨は、光学式研磨終点検出法により研磨終点をモニターしながらおこなった。すなわち、研磨の進行に伴ってタンタルからなるバリア層が露出し始めて生じる反射率の低下がほぼ止まって一定となる研磨終点まで研磨したのち、さらに３０秒間オーバー研磨をおこなった。研磨終点ではバリア層上の銅膜の一部を除き除去されていて、オーバー研磨をおこなうことにより、この一部残った余剰の銅膜が除去された。 Polishing of the wafer with a pattern used for polishing the polishing composition was performed while monitoring the polishing end point by an optical polishing end point detection method. That is, as the polishing progresses, the barrier layer made of tantalum begins to be exposed, and after the polishing is finished until the polishing end point at which the decrease in reflectivity almost stops and becomes constant, overpolishing is further performed for 30 seconds. At the polishing end point, a part of the copper film on the barrier layer was removed, and the excess copper film remaining in part was removed by overpolishing.
　（２）ディッシング量
　上記パターン付きウェハの研磨の後、配線幅および配線間隔が１００μｍのパターンについて、プロファイラーＨＲＰ－１００（ＫＬＡ－Ｔｅｎｃｏｒ社製）によりタンタル膜面と銅膜面との表面段差すなわちディッシング量を測定して、研磨により銅配線パターン面がタンタル膜面よりえぐられた度合いを評価した。 (2) Dishing amount After polishing the wafer with the above pattern, for a pattern having a wiring width and wiring interval of 100 μm, a profile difference between the tantalum film surface and the copper film surface, that is, dishing by a profiler HRP-100 (manufactured by KLA-Tencor) The amount was measured, and the degree to which the copper wiring pattern surface was removed from the tantalum film surface by polishing was evaluated.
　なお、表１～６中、研磨終点とは、上述における「バリア層上の銅膜一部を除き除去されて、バリア層が露出した」時点までの研磨時間であり、オーバー研磨時間はその後の研磨時間である。総研磨時間は研磨終点とオーバー研磨時間との合計である。ディッシングの測定はセンターチップとエッジチップとに分けて行った。センターチップとはウェハ上に存在する２０ｍｍ角のチップのうち、中心部にあるチップのことであり、エッジチップとはウェハ上に存在する２０ｍｍ角のチップのうち、最も端部に近いチップのことである。センターチップおよびエッジチップのそれぞれの値は、５０ｎｍ以下、特に３０ｎｍ以下であることが好ましい。センターチップとエッジチップのディッシング量の差は、２０ｎｍ以下、特に１０ｎｍ以下であることが好ましい。 In Tables 1 to 6, the polishing end point is the polishing time up to the point of time when the “barrier layer is exposed by removing a part of the copper film on the barrier layer” in the above-mentioned, and the over-polishing time is the subsequent polishing time. Polishing time. The total polishing time is the sum of the polishing end point and the over polishing time. The dishing measurement was performed separately for the center chip and the edge chip. The center chip is the chip at the center of the 20 mm square chips existing on the wafer, and the edge chip is the chip closest to the end of the 20 mm square chips present on the wafer. It is. Each value of the center chip and the edge chip is preferably 50 nm or less, particularly preferably 30 nm or less. The difference in dishing amount between the center chip and the edge chip is preferably 20 nm or less, particularly preferably 10 nm or less.
　研磨後のパターン付きウェハの概略断面図を図４（ｂ）に示す。図４（ｂ）では絶縁層２の凸部上では、銅膜からなる配線金属層４は完全に研磨され、タンタル膜からなるバリア層３の表面が露出している。また絶縁層２の凹部上では、絶縁層２の凸部上のバリア層３の表面に対して、符号７で示される深さだけえぐられて研磨されている。この表面段差の高さをディッシング量７とした。一方、図４（ｃ）は理想的に研磨されたパターン付きウェハの概略断面図であって、このような表面段差を生じることなく、埋め込み配線が形成されている。 Schematic cross-sectional view of the patterned wafer after polishing is shown in FIG. In FIG. 4B, on the convex portion of the insulating layer 2, the wiring metal layer 4 made of a copper film is completely polished, and the surface of the barrier layer 3 made of a tantalum film is exposed. Further, on the concave portion of the insulating layer 2, the surface of the barrier layer 3 on the convex portion of the insulating layer 2 is polished by the depth indicated by reference numeral 7. The height of the surface step was defined as a dishing amount of 7. On the other hand, FIG. 4C is a schematic cross-sectional view of an ideally polished patterned wafer, in which embedded wiring is formed without causing such a surface step.
　＜銅残り＞
　ＳＥＭ写真により評価した。具体的には、加速電圧を２ＫＶとし、２０００倍の倍率で、０．１８μｍの線幅の銅線間部分について銅が残っているかどうかで検査した。銅残りがほとんど観察されない場合を○、される場合を×とした。 <Copper residue>
Evaluation was made by SEM photographs. Specifically, the acceleration voltage was set to 2 KV, and an inspection was performed by checking whether or not copper remained in the portion between the copper wires having a line width of 0.18 μm at a magnification of 2000 times. The case where the copper residue was hardly observed was evaluated as ◯, and the case where the copper residue was observed as x.
　＜ピット＞
　ＳＥＭ写真により評価した。具体的には、加速電圧を２ＫＶとし、５００００倍の倍率で、表面の凹凸について調査した。凹凸がまったく観察されない場合を◎、凹凸がほとんど観察されない場合を○、凹凸が観察される場合を×とした、
　なお、どの例においても、パターンのエロージョンは良好であった。 <Pit>
Evaluation was made by SEM photographs. Specifically, the surface unevenness was investigated at an acceleration voltage of 2 KV and a magnification of 50000 times. ◎ when the unevenness is not observed at all, ○ when the unevenness is hardly observed, and × when the unevenness is observed,
In all examples, the pattern erosion was good.
　評価結果を表１～６に示す。 Evaluation results are shown in Tables 1-6.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　実施例は全て、ディッシング量、銅残り、ピット共良好な結果を示した。これに対し、その他の比較例は、全て、ディッシング量、銅残り、ピットのいずれかが不十分な値を示した。たとえば、例（比較例）６５および６６を見ると、坦性向上剤が含まれておらず、ドデシルベンゼンスルホン酸だけが添加されているため、銅残りやピットは満足できる結果である一方、ディッシング量が悪化している。これに対し、例えば例２や例４３は、特定の平坦性向上剤が含まれているため、銅残りやピットを悪化させることなく、ディッシングが非常に向上していることが分かる。 All examples showed good results for dishing amount, copper residue, and pits. On the other hand, all the other comparative examples showed insufficient values for the dishing amount, the remaining copper, or the pits. For example, looking at examples (comparative examples) 65 and 66, since no carrier improver is contained and only dodecylbenzenesulfonic acid is added, copper residue and pits are satisfactory, while dishing The amount is getting worse. On the other hand, for example, Example 2 and Example 43 contain a specific flatness improver, so that it can be seen that dishing is greatly improved without deteriorating copper residue and pits.
　また、例８２～８４をみると、ベンズイミダゾールが入っているにもかかわらず、オレイン酸が含まれており、銅残りやピットが悪化していることが分かる。 Further, in Examples 82 to 84, it can be seen that although benzimidazole is contained, oleic acid is contained, and the copper residue and pits are deteriorated.
　本発明を詳細にまた特定の実施態様を参照して説明したが、本発明の精神と範囲を逸脱することなく様々な変更や修正を加えることができることは、当業者にとって明らかである。
　本出願は、２００８年８月２８日出願の日本特許出願２００８－２１８９４４および２００８年１０月１６日出願の日本特許出願２００８－２６７４５０に基づくものであり、その内容はここに参照として取り込まれる。 Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2008-218944 filed on August 28, 2008 and Japanese Patent Application No. 2008-267450 filed on October 16, 2008, the contents of which are incorporated herein by reference.
　本発明によれば、第１研磨工程における銅配線の研磨速度を良好としつつ、ディッシングの問題を解決し、エロージョンも悪化させずかつ銅残りや銅配線上のピットの問題を解消できる、第１研磨工程用の新規な研磨用組成物が得られる。 According to the present invention, it is possible to solve the problem of dishing while improving the polishing rate of the copper wiring in the first polishing process, and to solve the problem of copper residue and pits on the copper wiring without deteriorating erosion. A novel polishing composition for the polishing process is obtained.
　１　　Ｓｉ基板
　２　　絶縁層
　３　　バリア層
　４　　配線金属層
　６　　銅埋込み配線
　７　　ディッシング量
　８　　銅膜の初期膜厚
　９　　銅膜の初期段差
　１７　ディッシング部分
　１８　エロージョン部分
　１９　最大段差
　２０　Ｇｌｏｂａｌ部
　２１　銅残り
　２２　銅残りのない部分
　２３　配線密度の高い箇所 DESCRIPTION OF SYMBOLS 1 Si substrate 2 Insulating layer 3 Barrier layer 4 Wiring metal layer 6 Copper embedding wiring 7 Dishing amount 8 Initial film thickness of copper film 9 Initial step of copper film 17 Dishing part 18 Erosion part 19 Maximum step 20 Global part 21 Copper remaining part 22 Copper No remaining part 23 High wiring density

Claims (12)

  1. 　絶縁層上にバリア層を介して設けられた銅層を研磨して、銅埋め込み配線と絶縁層とを交互に形成するパターン形成において、前記銅層に隣接した前記バリア層が露出するまで研磨する工程に用いられる研磨用組成物であって、
    　ドデシルベンゼンスルホン酸成分と、
    　アルケニルコハク酸成分、ポリオキシエチレンアルキルエーテルカルボン酸成分およびポリオキシエチレンアルキルエーテルリン酸成分からなる群から選ばれる少なくとも一つの平坦性向上剤と
    を含む、研磨用組成物。     The copper layer provided on the insulating layer via the barrier layer is polished, and in the pattern formation in which the copper embedded wiring and the insulating layer are alternately formed, the copper layer is polished until the barrier layer adjacent to the copper layer is exposed. A polishing composition used in the process,
    A dodecylbenzenesulfonic acid component;
    A polishing composition comprising at least one flatness improver selected from the group consisting of an alkenyl succinic acid component, a polyoxyethylene alkyl ether carboxylic acid component, and a polyoxyethylene alkyl ether phosphoric acid component.
  2. 　更に脂環族樹脂酸を含む、請求項１に記載の研磨用組成物。 The polishing composition according to claim 1, further comprising an alicyclic resin acid.
  3. 　前記脂環族樹脂酸がロジンである、請求項２に記載の研磨用組成物。 The polishing composition according to claim 2, wherein the alicyclic resin acid is rosin.
  4. 　更にイミダゾール誘導体を含む、請求項１～３のいずれかに記載の研磨用組成物。 The polishing composition according to any one of claims 1 to 3, further comprising an imidazole derivative.
  5. 　更に砥粒としてコロイダルシリカを含む、請求項１～４のいずれかに記載の研磨用組成物。 The polishing composition according to any one of claims 1 to 4, further comprising colloidal silica as abrasive grains.
  6. 　更に酸化剤を含む、請求項１～５のいずれかに記載の研磨用組成物。 The polishing composition according to claim 1, further comprising an oxidizing agent.
  7. 　更に錯体形成剤を含む、請求項１～６のいずれかに記載の研磨用組成物。 The polishing composition according to any one of claims 1 to 6, further comprising a complex-forming agent.
  8. 　研磨用組成物中のオレイン酸の含有量が０．０３質量％以下である、請求項１～７のいずれかに記載の研磨用組成物。 The polishing composition according to any one of claims 1 to 7, wherein the content of oleic acid in the polishing composition is 0.03% by mass or less.
  9. 　半導体集積回路装置の製造方法であって、
    　当該半導体集積回路装置が、溝を有する絶縁層と、当該溝に形成された銅埋め込み配線とを備えており、
    　当該絶縁層上にバリア層と銅層とがこの順に形成された当該半導体集積回路装置用の多層構造体を、請求項１～８のいずれかに記載の研磨用組成物を用いて、前記銅層に隣接した前記バリア層が露出するまで研磨することを含む、半導体集積回路装置の製造方法。     A method for manufacturing a semiconductor integrated circuit device, comprising:
    The semiconductor integrated circuit device includes an insulating layer having a groove and a copper embedded wiring formed in the groove,
    A multilayer structure for a semiconductor integrated circuit device, in which a barrier layer and a copper layer are formed in this order on the insulating layer, the polishing composition according to any one of claims 1 to 8, and Polishing until the said barrier layer adjacent to a layer is exposed, The manufacturing method of a semiconductor integrated circuit device.
  10. 　前記バリア層が、Ｔａ、ＴａＮおよびＴｉＮからなる群から選ばれる少なくとも１種を含む、請求項９に記載の半導体集積回路装置の製造方法。 10. The method for manufacturing a semiconductor integrated circuit device according to claim 9, wherein the barrier layer includes at least one selected from the group consisting of Ta, TaN, and TiN.
  11. 　前記多層構造体が、前記絶縁層と前記バリア層との間にキャップ層を備えている、請求項９または１０に記載の半導体集積回路装置の製造方法。 11. The method for manufacturing a semiconductor integrated circuit device according to claim 9, wherein the multilayer structure includes a cap layer between the insulating layer and the barrier layer.
  12. 　前記溝を有する絶縁層が３以下の比誘電率を有する、請求項９～１１のいずれかに記載の半導体集積回路装置の製造方法。 12. The method of manufacturing a semiconductor integrated circuit device according to claim 9, wherein the insulating layer having the groove has a relative dielectric constant of 3 or less.
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* Cited by examiner, † Cited by third party
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WO2016016791A1 (en) 2014-07-28 2016-02-04 Idemitsu Kosan Co., Ltd (Ikc) 2,9-functionalized benzimidazolo[1,2-a]benzimidazoles as hosts for organic light emitting diodes (oleds)
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EP3054498A1 (en) 2015-02-06 2016-08-10 Idemitsu Kosan Co., Ltd. Bisimidazodiazocines
EP3053918A1 (en) 2015-02-06 2016-08-10 Idemitsu Kosan Co., Ltd 2-carbazole substituted benzimidazoles for electronic applications
EP3070144A1 (en) 2015-03-17 2016-09-21 Idemitsu Kosan Co., Ltd. Seven-membered ring compounds
WO2016157113A1 (en) 2015-03-31 2016-10-06 Idemitsu Kosan Co., Ltd. Benzimidazolo[1,2-a]benzimidazole carrying aryl- or heteroarylnitril groups for organic light emitting diodes
WO2017056055A1 (en) 2015-10-01 2017-04-06 Idemitsu Kosan Co., Ltd. Benzimidazolo[1,2-a]benzimidazole carrying triazine groups for organic light emitting diodes
WO2017056053A1 (en) 2015-10-01 2017-04-06 Idemitsu Kosan Co., Ltd. Benzimidazolo[1,2-a]benzimidazole carrying benzimidazolo[1,2-a]benzimidazolyl groups, carbazolyl groups, benzofurane groups or benzothiophene groups for organic light emitting diodes
WO2017056052A1 (en) 2015-10-01 2017-04-06 Idemitsu Kosan Co., Ltd. Benzimidazolo[1,2-a]benzimidazole carrying benzimidazolo[1,2-a]benzimidazolyl groups, carbazolyl groups, benzofurane groups or benzothiophene groups for organic light emitting diodes
WO2023189899A1 (en) * 2022-04-01 2023-10-05 株式会社フジミインコーポレーテッド Polishing composition

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