WO2018163861A1 - Cu-Ni ALLOY SPUTTERING TARGET AND PRODUCTION METHOD THEREFOR - Google Patents

Cu-Ni ALLOY SPUTTERING TARGET AND PRODUCTION METHOD THEREFOR Download PDF

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Publication number
WO2018163861A1
WO2018163861A1 PCT/JP2018/006685 JP2018006685W WO2018163861A1 WO 2018163861 A1 WO2018163861 A1 WO 2018163861A1 JP 2018006685 W JP2018006685 W JP 2018006685W WO 2018163861 A1 WO2018163861 A1 WO 2018163861A1
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Prior art keywords
alloy
less
mass
sputtering target
ingot
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PCT/JP2018/006685
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French (fr)
Japanese (ja)
Inventor
小見山　昌三
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三菱マテリアル株式会社
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Priority claimed from JP2017241103A external-priority patent/JP2018145518A/en
Application filed by 三菱マテリアル株式会社 filed Critical 三菱マテリアル株式会社
Priority to CN201880007717.5A priority Critical patent/CN110199051A/en
Publication of WO2018163861A1 publication Critical patent/WO2018163861A1/en

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/06—Alloys based on copper with nickel or cobalt as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon

Definitions

  • the present invention relates to a Cu—Ni alloy sputtering target and a manufacturing method thereof.
  • This application claims priority based on Japanese Patent Application No. 2017-042162 filed in Japan on March 6, 2017 and Japanese Patent Application No. 2017-241103 filed in Japan on December 15, 2017. Is incorporated herein by reference.
  • Al is widely used as a flat panel display such as a liquid crystal or an organic EL panel, or as a wiring film for a touch panel or the like.
  • miniaturization (narrowing) and thinning of the wiring film have been attempted, and a wiring film having a lower specific resistance than before has been demanded.
  • a wiring film using Cu or Cu alloy, which is a material having a specific resistance lower than that of Al, is provided.
  • Patent Document 1 discloses a Cu wiring protection made of a Cu alloy containing 20 wt% to 65 wt% of Ni, 0.2 wt% to 5.0 wt% of Al and / or Ti, and the remaining 90 mass% or more of Cu. A film and a Cu alloy sputtering target for forming this Cu wiring protective film are disclosed.
  • the glass substrate on which the wiring film is formed has been increased in size, and accordingly, the sputtering target itself for forming the protective film tends to be increased in size.
  • the conventional Cu alloy sputtering target as described in Patent Document 1 is enlarged, micro arc discharge (abnormal discharge) and splash may occur depending on sputtering conditions, and film formation cannot be performed satisfactorily. was there. That is, when a large sputtering target is used, a large amount of power is applied.
  • the present invention has been made in view of the above-described circumstances, and can form a Cu alloy film excellent in weather resistance, and can suppress the occurrence of micro arc discharge during film formation, and a Cu alloy sputtering target. It aims at providing the manufacturing method.
  • the Cu—Ni alloy sputtering target of the present invention contains Ni in the range of 16 mass% to 55 mass%, the hydrogen content is less than 5 mass ppm, and the oxygen content Is 500 mass ppm or less, with the balance being composed of Cu and inevitable impurities.
  • the main component is two elements of Cu and Ni
  • the variation in composition is smaller than that of a three-element or four-element alloy as in Patent Document 1.
  • the Ni content is in the range of 16 mass% or more and 55 mass% or less, the weather resistance of the formed Cu—Ni alloy film becomes high.
  • the hydrogen content is less than 5 ppm by mass and the oxygen content is limited to 500 ppm by mass or less, it is possible to suppress the occurrence of micro arc discharge during the sputtering film formation, and the sputter film formation. It becomes possible to carry out stably.
  • the number of voids having a maximum diameter of 2 ⁇ m or more is preferably 1 or less per 1 mm 2 region in the sputtering surface. In this case, since the amount of large voids having a maximum diameter of 2 ⁇ m or more is small, it is possible to more reliably suppress the occurrence of micro arc discharge during sputtering film formation.
  • the number of voids in this specification is a value measured by the measurement method described later.
  • the carbon content is preferably 500 mass ppm or less.
  • Large Cu alloy sputtering targets are usually manufactured through casting and hot rolling processes, but when cracks occur during hot rolling, micro arc discharge occurs at the cracks, so they are used as sputtering targets. There is a risk that it will not be possible.
  • hot rollability can be improved, cracking during hot rolling can be suppressed, and micro arc discharge can be suppressed.
  • a method for producing a Cu—Ni alloy sputtering target includes: Electrolytic Ni is heated and melted, held for 10 minutes or more at a temperature higher than the melting temperature of Ni for 10 minutes or more, and then cooled and solidified to obtain a Ni ingot, A melt casting step of melt-casting oxygen-free copper and the Ni ingot to obtain a Cu-Ni alloy ingot; Hot rolling is performed on a Cu—Ni alloy ingot obtained in the melt casting process to obtain a Cu—Ni alloy rolled sheet having an average crystal grain size of 100 ⁇ m or less and a Vickers hardness of 60 Hv to 120 Hv. Process, The surface of the Cu—Ni alloy rolled plate that is to be a sputter surface is ground and polished, and the surface roughness of the sputter surface is adjusted to a maximum height Rz of 5 ⁇ m or less.
  • a Cu—Ni alloy sputtering target capable of forming a Cu—Ni alloy film having excellent weather resistance and suppressing the occurrence of micro arc discharge during the film formation.
  • the Cu—Ni alloy sputtering target of this embodiment is used, for example, when forming a protective film laminated on a wiring film such as a flat panel display or a touch panel, or a Cu wiring film made of Cu or Cu alloy. It is what is done.
  • the shape and size of the Cu—Ni alloy sputtering target of the present embodiment are not limited, and may be a disk shape or a rectangular plate shape, or a cylindrical shape.
  • a backing plate made of copper, stainless steel, or titanium may be fixed to one surface of the target via solder such as indium, indium-tin alloy, or tin.
  • a cylindrical backing tube made of the same material may be fixed to the inner peripheral surface of the target via the same solder material.
  • the effect of the present invention is remarkable when the sputtering target is a large-sized sputtering target having an area of 100000 mm 2 or more, and the effect is remarkable when the sputtering target is flat.
  • the sputtering surface refers to a region of the surface of the sputtering target that is used for sputtering by being irradiated with plasma.
  • the Cu—Ni alloy sputtering target of the present embodiment contains Ni in the range of 16 mass% to 55 mass%, the hydrogen content is less than 5 mass ppm, and the oxygen content is 500 mass ppm or less.
  • the balance has a composition composed of Cu and inevitable impurities.
  • the number of voids having a maximum diameter of 2 ⁇ m or more is set to 1 or less per 1 mm 2 region in the sputtering surface. A specific method for measuring the number of voids will be described later. Furthermore, in the Cu—Ni alloy sputtering target of this embodiment, the carbon content of the inevitable impurities is set to 500 mass ppm or less.
  • Ni is an element having an effect of improving the weather resistance of Cu.
  • discoloration of the formed Cu—Ni alloy film can be suppressed.
  • the Ni content is set in the range of 16 mass% to 55 mass%.
  • the Ni content is preferably in the range of 20% by mass to 50% by mass, and more preferably in the range of 25% by mass to 45% by mass. .
  • the hydrogen content of the Cu—Ni alloy sputtering target correlates with the number of voids, and that the number of voids tends to decrease when the hydrogen content is small.
  • the hydrogen content is set to less than 5 ppm by mass.
  • the hydrogen content is preferably less than 4 ppm by mass, and more preferably less than 3 ppm by mass.
  • the lower limit of the hydrogen content is usually 0.1 mass ppm or more. Even if the hydrogen content is less than 0.1 mass ppm, the effect of reducing the number of voids is not improved. On the other hand, the work for reducing the hydrogen content becomes complicated and the production cost may increase.
  • Oxygen content 500 mass ppm or less
  • oxygen content 500 mass ppm or less. It is assumed that oxygen is present as the oxide that remains when a part of the refractory of the melting furnace is caught in the ingot during melting and casting of the Cu and Ni oxides and the target constituting the Cu—Ni alloy sputtering target. Is done. Since these oxides easily emit secondary electrons, if the content of oxide in the Cu—Ni alloy sputtering target is excessive, the amount of secondary electrons emitted increases during sputtering film formation. The present inventors have found that the number of occurrences of micro arc discharge may increase. For this reason, in this embodiment, the oxygen content is set to 500 mass ppm or less.
  • the oxygen content is preferably 300 ppm by mass or less, and more preferably 50 ppm by mass or less.
  • the lower limit of the oxygen content is usually 0.1 mass ppm or more. Even if the oxygen content is less than 0.1 mass ppm, the effect of reducing the emission amount of secondary electrons is not improved. On the other hand, the work for reducing the oxygen content becomes complicated and the production cost may increase. is there.
  • Carbon is an element that may cause cracking in the manufacturing process of the Cu—Ni alloy sputtering target of the present embodiment. Cracking proceeds from the outer periphery of the rolled Cu—Ni alloy sheet during rolling of the Cu—Ni alloy. If it is a fine crack, it can be removed by machining or the like, but if the carbon content exceeds 500 ppm, the crack tends to increase, and depending on the machining, it may be difficult to completely remove the crack. This has been found by the inventors' research. If cracks exist in the Cu—Ni alloy sputtering target, the number of occurrences of micro arc discharge starting from the cracks may increase during sputtering film formation. That is, it has been found by the present inventors that the low carbon content means that the amount of cracks that causes micro arc discharge during sputtering film formation is small. For this reason, in this embodiment, the carbon content is set to 500 mass ppm or less.
  • the carbon content is preferably 300 mass ppm or less, and more preferably 50 mass ppm or less. .
  • the lower limit of the carbon content is usually 3 ppm by mass or more. Even if the carbon content is less than 3 ppm by mass, the effect of reducing fine cracks is not improved. On the other hand, the work for reducing the carbon content becomes complicated and the production cost may increase.
  • the number of voids having a maximum diameter of 2 ⁇ m or more is limited to one or less per 1 mm 2 region in the sputtering surface. A specific method for measuring the number of voids will be described later.
  • the Cu—Ni alloy sputtering target of this embodiment is manufactured through processes such as a melt casting process, a hot rolling process, (leveler processing process / cold rolling process, heat treatment process), and a machining process. Below, each process is demonstrated.
  • melt casting process Cu and Ni are melt cast to obtain a Cu—Ni alloy ingot.
  • the melting raw material is weighed so that the above-described target composition is obtained.
  • a melting raw material it is preferable to use Cu having a purity of 99.99% by mass or more and Ni having a purity of 99.9% by mass or more.
  • oxygen-free copper having an oxygen concentration of 10 mass ppm or less and a purity of 99.99 mass% or more is preferably used.
  • Ni melting material As a Ni melting material, it is preferable to use a material obtained by subjecting electrolytic Ni purified by an electrolytic method to a hydrogen reduction treatment.
  • the hydrogen reduction treatment is usually performed because electrolytic Ni contains more than 10 ppm by mass of hydrogen, so when used as a raw material for dissolution, hydrogen in electrolytic Ni remains in the Cu—Ni alloy ingot. This is because voids may be generated. If voids are generated in the Cu—Ni alloy ingot, the voids may remain on the target and cause micro arc discharge during sputtering film formation.
  • Electrolytic Ni contains excess hydrogen above its solubility. Therefore, when Cu and electrolytic Ni are dissolved to form a molten Cu—Ni alloy, the hydrogen in electrolytic Ni is the molten Cu—Ni alloy (liquid phase). Blend into. On the other hand, since hydrogen has a low solubility in the solid phase of the Cu—Ni alloy, hydrogen gas bubbles are generated at the boundary between the liquid phase and the solid phase when the melt of the Cu—Ni alloy solidifies. The solidification of the molten metal and the generation of bubbles proceed simultaneously, and the bubbles that have not been discharged to the outside of the molten metal are left as voids in the Cu—Ni alloy ingot.
  • electrolytic Ni As the hydrogen reduction treatment of electrolytic Ni, electrolytic Ni is heated and melted, held at a temperature 10 to 50 ° C. higher than the melting temperature of Ni for 2 to 30 minutes, then cooled and solidified to form a Ni casting.
  • a method of obtaining a lump can be used. More preferably, a Ni ingot may be obtained by holding at a temperature 15 ° C. to 35 ° C. higher than the melting temperature of Ni for 10 minutes to 20 minutes and then cooling to solidify.
  • the hydrogen reduction treatment of electrolytic Ni it is preferable to use an induction melting furnace as the heating device.
  • the hydrogen reduction treatment is preferably performed in a vacuum atmosphere or an inert gas atmosphere.
  • the Ni ingot obtained by this hydrogen reduction treatment preferably has a hydrogen content of 10 mass ppm or less, particularly 5 mass ppm or less. From the viewpoint of manufacturing cost, the hydrogen content of the Ni ingot may be 0.1 mass ppm or more.
  • an induction melting furnace When melting and casting the weighed Cu and Ni, it is preferable to use an induction melting furnace in order to sufficiently mix the melting raw materials and make the composition of the molten metal uniform. By preventing oxidation of Cu and Ni, which are alloy constituents, at the time of melting, generation of oxide is suppressed. In order to prevent oxidation during melting, it is preferable to dissolve in a vacuum atmosphere or an inert gas atmosphere. When melting in an air atmosphere in consideration of productivity, use a carbon crucible to hold the melting raw material, or cover the molten metal surface with carbon particles and carbon powder to make the molten metal into a reducing atmosphere. A method of keeping may be adopted.
  • the Cu—Ni alloy ingot obtained in the melt casting process is cut into a predetermined length and then hot rolled.
  • the conditions for hot rolling are preferably a rolling reduction per pass of 10% to 20% and a hot rolling temperature of 550 ° C to 1000 ° C. More preferably, the rolling reduction per pass is 11% to 17%, and the hot rolling temperature is 800 ° C to 1000 ° C.
  • the rolling reduction is a value calculated from the following equation.
  • Reduction ratio (%) ⁇ (Cu—Ni alloy thickness before hot rolling pass ⁇ Cu—Ni alloy thickness after hot rolling pass) / Cu—Ni alloy thickness before hot rolling pass ⁇ ⁇ 100
  • the overall rolling reduction in the hot rolling process is preferably 50% or more and 90% or less, and more preferably, the overall rolling reduction in the hot rolling process is 60% or more and 80% or less.
  • a Cu—Ni alloy rolled sheet having an average crystal grain size of 100 ⁇ m or less and a Vickers hardness of 60 Hv to 120 Hv can be obtained. More preferably, the average crystal grain size may be 5 ⁇ m or more and 50 ⁇ m or less, and the Vickers hardness may be 80 Hv or more and 110 Hv or less.
  • Leveler processing process / cold rolling process, heat treatment process The Cu—Ni alloy rolled sheet obtained in the hot rolling process described above may be subjected to a leveler process or a cold rolling process in order to improve the flatness of the rolled sheet.
  • heat treatment is performed at a temperature of 550 ° C. to 850 ° C. for 1 to 2 hours. It is preferable to cool in the atmosphere. More preferably, the heat treatment may be performed under the condition of holding at a temperature of 650 ° C. or higher and 850 ° C. or lower for 1 to 2 hours, and then allowed to cool in the air.
  • the machining step grinding and polishing are performed on the surface to be the sputtered surface of the Cu—Ni alloy rolled plate obtained as described above. It is preferable to adjust the surface roughness of the sputter surface so that the maximum height Rz is 5 ⁇ m or less. More preferably, the surface roughness of the sputter surface may be adjusted to be 0.5 ⁇ m or more and 3 ⁇ m or less at the maximum height Rz.
  • the Cu—Ni alloy sputtering target of the present embodiment is manufactured through the processes as described above.
  • This Cu—Ni alloy sputtering target is soldered or brazed to a Cu backing plate as necessary, and is attached to a sputtering apparatus, and a Cu—Ni alloy film is formed on the opposing substrate by sputtering. .
  • the sputtered Cu—Ni alloy film has the same composition as the above-described Cu—Ni alloy sputtering target.
  • the components are two elements of Cu and Ni, the variation in composition is reduced. Since the Ni content is in the range of 16 mass% or more and 55 mass% or less, the weather resistance of the formed Cu—Ni alloy film becomes high.
  • the hydrogen content is less than 5 ppm by mass
  • the oxygen content is limited to 500 ppm by mass or less
  • the amount of voids and oxides mixed is small. Generation of micro arc discharge can be suppressed, and sputtering film formation can be performed stably.
  • the number of voids having a maximum diameter of 2 ⁇ m or more is 1 or less per 1 mm 2 region in the sputtering surface. The occurrence of arc discharge can be more reliably suppressed.
  • the hot rolling property can be improved, and during hot rolling, The occurrence of cracks can be suppressed.
  • this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
  • a large sputtering target having a flat plate shape and an area of the sputtering surface of 100,000 mm 2 or more has been described.
  • the shape of the Cu—Ni alloy sputtering target is not particularly limited, and is a disk shape. Alternatively, it may have a rectangular flat plate shape or a cylindrical shape.
  • the area of the sputter surface is not limited to the above range. In either case, the effects of the present invention can be obtained.
  • Electrolytic Ni production of hydrogen reduced Ni ingot
  • Electrolytic Ni purity: 99.99% by mass or more
  • the hydrogen content in the electrolytic Ni was in the range of 11 to 15 ppm by mass.
  • Electrolytic Ni was put into an alumina crucible. Next, electrolytic Ni is heated and melted in a vacuum atmosphere using a high-frequency induction heating furnace, held at a temperature 10 to 50 ° C. higher than the melting temperature of Ni for 2 to 15 minutes, and then cooled and solidified. Thus, a hydrogen reduced Ni ingot was obtained.
  • Table 1 shows the melt retention time of the hydrogen reduction treatment and the hydrogen content of the obtained hydrogen reduced Ni ingot.
  • Comparative Example 1 the hydrogen reduction treatment of electrolytic Ni was not performed.
  • the hydrogen content of the electrolytic Ni and hydrogen reduced Ni ingots was analyzed by an inert gas melting-thermal conductivity method (JISZ2614).
  • Example 7 of the present invention when the target material was cut out, the cracked portion of the rolled Cu—Ni alloy plate was removed.
  • the number of voids was measured by the following method. Note that the number of voids in this specification is a value measured by the following method.
  • the sputter surface of the evaluation target was equally divided into four equal parts, and samples for tissue observation were cut out from the respective portions.
  • the sputter surfaces of these four samples were polished using # 180 to # 2400 polishing paper in order from coarse to fine, and then polished with an abrasive having an average particle size of 1 ⁇ m. According to this polishing method, the surface roughness is approximately Ra: less than 0.1 ⁇ m.
  • each region of 0.5 mm ⁇ 0.5 mm was randomly selected from the four sputtered surfaces of the polished samples, and each region was darkened at a magnification of 100 times with an optical microscope. It was observed as a field image. Since this is a dark field image, if there is a void (dent) of a certain size or more on the sputter surface, that portion is detected as a point that shines white. In each region, the number of voids having a maximum length of 2 ⁇ m or more was counted. Evaluation was made with “OK” when the number of voids detected within 1 mm 2 totaling 4 regions was 1 or 0, and “NG” when 2 or more. The evaluation results are shown in Table 2.
  • a target for evaluation was attached to the sputtering apparatus, pre-sputtering was performed for 30 minutes from the start of use under the conditions of ultimate vacuum: 5 ⁇ 10 ⁇ 4 Pa, gas pressure: argon 0.3 Pa, sputtering power: direct current 1000 W, then micro sputtering
  • the number of arc discharges was examined.
  • the micro arc discharge was detected by adding a micro arc monitor manufactured by Landmark Technology Co., Ltd. to the sputtering power source and detecting a decrease in the discharge voltage.
  • Table 2 shows the results of counting the number of micro arc discharges.
  • a non-alkali glass substrate of 50 mm ⁇ 50 mm ⁇ 0.7 mm was placed facing the target for evaluation so that the distance between the substrates was 60 mm, the ultimate vacuum: 5 ⁇ 10 ⁇ 4 Pa, the gas pressure: argon 0.3 Pa, Sputtering power: Sputtering was performed under the condition of 600 W DC, and a Cu—Ni alloy film having a thickness of 150 nm was formed on the substrate.
  • the formed Cu—Ni alloy film was subjected to a constant temperature and humidity test for 250 hours under a constant temperature and humidity condition of 70 ° C. and 90% relative humidity, and then the surface of the Cu—Ni alloy film was visually observed. Then, the case where the color change was recognized was evaluated as “NG”, and the case where the color change was not confirmed was evaluated as “OK”.
  • the evaluation results are shown in Table 2.
  • Comparative Example 1 In Comparative Example 1 in which the hydrogen content was 5 mass ppm or more, the number of voids increased and the number of micro arc discharges increased. In Comparative Example 2 in which the oxygen content exceeds 500 ppm by mass, the number of micro arc discharges is increased, and the formed Cu—Ni alloy film is discolored after the constant temperature and humidity test, resulting in insufficient weather resistance. It was. In Comparative Example 3 in which the Ni content was less than 16% by mass, the formed Cu—Ni alloy film was discolored after the constant temperature and humidity test, and the weather resistance was insufficient. In Comparative Example 4 where the Ni content exceeds 55 mass%, sputtering could not be performed. It is presumed that the magnetism has become stronger.
  • the number of voids is small, the number of micro arc discharges is suppressed, and stable sputtering film formation I was able to. Further, the formed Cu—Ni alloy film was excellent in weather resistance.
  • a Cu—Ni alloy sputtering target capable of forming a Cu—Ni alloy film having excellent weather resistance and suppressing the occurrence of micro arc discharge during the film formation. It was confirmed that it was possible.
  • the Cu—Ni alloy sputtering target of the present invention can be used industrially because it can form a Cu—Ni alloy film having excellent weather resistance and suppress the occurrence of micro arc discharge during the film formation.

Abstract

This Cu-Ni alloy sputtering target has a composition such that: Ni is contained in the range of 16 mass% to 55 mass%; the hydrogen content is less than 5 mass ppm, the oxygen content is 500 mass ppm or less, and the carbon content is 500 mass ppm or less; and the balance is Cu and unavoidable impurities. The number of voids with a maximum diameter of at least 2 µm is not more than 1 per 1 mm2 region in the sputtering surface.

Description

Ｃｕ－Ｎｉ合金スパッタリングターゲット及びその製造方法Cu—Ni alloy sputtering target and method for producing the same
　本発明は、Ｃｕ－Ｎｉ合金スパッタリングターゲット及びその製造方法に関する。
　本願は、２０１７年３月６日に日本で出願された特願２０１７－０４２１６２号、および２０１７年１２月１５日に日本で出願された特願２０１７－２４１１０３号に基づき優先権を主張し、それらの内容をここに援用する。 The present invention relates to a Cu—Ni alloy sputtering target and a manufacturing method thereof.
This application claims priority based on Japanese Patent Application No. 2017-042162 filed in Japan on March 6, 2017 and Japanese Patent Application No. 2017-241103 filed in Japan on December 15, 2017. Is incorporated herein by reference.
　従来、液晶や有機ＥＬパネルなどのフラットパネルディスプレイや、タッチパネル等の配線膜としてＡｌが広く使用されている。最近では、配線膜の微細化（幅狭化）および薄膜化が図られており、従来よりも比抵抗の低い配線膜が求められている。上述の配線膜の微細化および薄膜化にともない、Ａｌよりも比抵抗の低い材料であるＣｕまたはＣｕ合金を用いた配線膜が提供されている。 Conventionally, Al is widely used as a flat panel display such as a liquid crystal or an organic EL panel, or as a wiring film for a touch panel or the like. Recently, miniaturization (narrowing) and thinning of the wiring film have been attempted, and a wiring film having a lower specific resistance than before has been demanded. With the miniaturization and thinning of the wiring film described above, a wiring film using Cu or Cu alloy, which is a material having a specific resistance lower than that of Al, is provided.
　しかし、比抵抗の低いＣｕまたはＣｕ合金からなるＣｕ配線膜は、耐候性が低く、特に湿度を有する雰囲気中で変色しやすいといった問題があった。このため、Ｃｕ配線膜に保護膜を設けることが行なわれている。
　例えば、特許文献１には、Ｎｉを２０ｗｔ％から６５ｗｔ％、Ａｌ及び／又はＴｉを０．２ｗｔ％から５．０ｗｔ％含み、残部の９０質量％以上がＣｕであるＣｕ合金からなるＣｕ配線保護膜と、このＣｕ配線保護膜を形成するためのＣｕ合金スパッタリングターゲットが開示されている。 However, a Cu wiring film made of Cu or Cu alloy having a low specific resistance has a problem that it has low weather resistance and is likely to be discolored particularly in an atmosphere having humidity. For this reason, a protective film is provided on the Cu wiring film.
For example, Patent Document 1 discloses a Cu wiring protection made of a Cu alloy containing 20 wt% to 65 wt% of Ni, 0.2 wt% to 5.0 wt% of Al and / or Ti, and the remaining 90 mass% or more of Cu. A film and a Cu alloy sputtering target for forming this Cu wiring protective film are disclosed.
特開２０１４－１０５３６２号公報JP 2014-105362 A
　ところで、最近では、配線膜を形成するガラス基板の大型化が進んでおり、これに伴って、保護膜成膜用のスパッタリングターゲット自体も大型化する傾向にある。しかしながら、特許文献１に記載されているような従来のＣｕ合金スパッタリングターゲットは、大型化すると、スパッタ条件によってはマイクロアーク放電（異常放電）及びスプラッシュが発生し、良好に成膜が実施できないといった問題があった。すなわち、大型のスパッタリングターゲットを用いる場合には、大電力を投入することになるため、スパッタリングターゲットのスパッタ面にボイドが発生しているか、あるいは酸化物等の介在物が存在していると、マイクロアーク放電が発生しやすくなり、スパッタリングターゲットが局所的に溶融してパーティクルが発生し、Ｃｕ合金膜を良好に成膜できなくなるおそれがあった。大型でないスパッタリングターゲットにおいて成膜効率を向上させるために大電力を投入した場合も同様である。 By the way, recently, the glass substrate on which the wiring film is formed has been increased in size, and accordingly, the sputtering target itself for forming the protective film tends to be increased in size. However, when the conventional Cu alloy sputtering target as described in Patent Document 1 is enlarged, micro arc discharge (abnormal discharge) and splash may occur depending on sputtering conditions, and film formation cannot be performed satisfactorily. was there. That is, when a large sputtering target is used, a large amount of power is applied. Therefore, if voids are generated on the sputtering surface of the sputtering target or inclusions such as oxides are present, Arc discharge tends to occur, the sputtering target melts locally and particles are generated, and the Cu alloy film may not be formed satisfactorily. The same applies to the case where a large amount of electric power is applied to improve the film formation efficiency in a sputtering target that is not large.
　この発明は、前述した事情に鑑みてなされたものであって、耐候性に優れたＣｕ合金膜を成膜でき、成膜時のマイクロアーク放電の発生を抑制することができるＣｕ合金スパッタリングターゲットおよびその製造方法を提供することを目的とする。 The present invention has been made in view of the above-described circumstances, and can form a Cu alloy film excellent in weather resistance, and can suppress the occurrence of micro arc discharge during film formation, and a Cu alloy sputtering target. It aims at providing the manufacturing method.
　上記の課題を解決するために、本発明のＣｕ－Ｎｉ合金スパッタリングターゲットは、Ｎｉを１６質量％以上５５質量％以下の範囲で含有し、水素の含有量が５質量ｐｐｍ未満、酸素の含有量が５００質量ｐｐｍ以下であり、残部がＣｕおよび不可避不純物からなる組成を有する。 In order to solve the above problems, the Cu—Ni alloy sputtering target of the present invention contains Ni in the range of 16 mass% to 55 mass%, the hydrogen content is less than 5 mass ppm, and the oxygen content Is 500 mass ppm or less, with the balance being composed of Cu and inevitable impurities.
　本発明のＣｕ－Ｎｉ合金スパッタリングターゲットによれば、主成分がＣｕとＮｉの二元素であるため、特許文献１のような三元素または四元素系合金に比べて、組成のばらつきが小さくなる。また、Ｎｉの含有量が１６質量％以上５５質量％以下の範囲とされているので、成膜されたＣｕ－Ｎｉ合金膜の耐候性が高くなる。 According to the Cu—Ni alloy sputtering target of the present invention, since the main component is two elements of Cu and Ni, the variation in composition is smaller than that of a three-element or four-element alloy as in Patent Document 1. Further, since the Ni content is in the range of 16 mass% or more and 55 mass% or less, the weather resistance of the formed Cu—Ni alloy film becomes high.
　さらに、水素の含有量が５質量ｐｐｍ未満で、酸素の含有量が５００質量ｐｐｍ以下と制限されているので、スパッタ成膜時において、マイクロアーク放電が発生することを抑制でき、スパッタ成膜を安定して行うことが可能となる。 Further, since the hydrogen content is less than 5 ppm by mass and the oxygen content is limited to 500 ppm by mass or less, it is possible to suppress the occurrence of micro arc discharge during the sputtering film formation, and the sputter film formation. It becomes possible to carry out stably.
　本発明のＣｕ－Ｎｉ合金スパッタリングターゲットにおいては、最大径が２μｍ以上のボイドの数が、スパッタ面内の１ｍｍ２の領域あたり１個以下であることが好ましい。この場合は、最大径が２μｍ以上とサイズが大きいボイドの混入量が少ないので、スパッタ成膜時におけるマイクロアーク放電の発生をより確実に抑制することが可能となる。本明細書におけるボイドの数は、後述した測定方法で測定される値とする。 In the Cu—Ni alloy sputtering target of the present invention, the number of voids having a maximum diameter of 2 μm or more is preferably 1 or less per 1 mm 2 region in the sputtering surface. In this case, since the amount of large voids having a maximum diameter of 2 μm or more is small, it is possible to more reliably suppress the occurrence of micro arc discharge during sputtering film formation. The number of voids in this specification is a value measured by the measurement method described later.
　また、本発明のＣｕ－Ｎｉ合金スパッタリングターゲットにおいては、炭素の含有量が５００質量ｐｐｍ以下であることが好ましい。
　大型のＣｕ合金スパッタリングターゲットは、通常、鋳造および熱間圧延の工程を経て製造されているが、熱間圧延時に割れが生じると、割れの部分でマイクロアーク放電が発生するためにスパッタリングターゲットとして使用できなくなるおそれがある。炭素の含有量を５００質量ｐｐｍ以下に制限することで、熱間圧延性を向上させることができ、熱間圧延時の割れの発生を抑制して、マイクロアーク放電を抑制できる。 In the Cu—Ni alloy sputtering target of the present invention, the carbon content is preferably 500 mass ppm or less.
Large Cu alloy sputtering targets are usually manufactured through casting and hot rolling processes, but when cracks occur during hot rolling, micro arc discharge occurs at the cracks, so they are used as sputtering targets. There is a risk that it will not be possible. By restricting the carbon content to 500 ppm by mass or less, hot rollability can be improved, cracking during hot rolling can be suppressed, and micro arc discharge can be suppressed.
　本発明の一態様に係るＣｕ－Ｎｉ合金スパッタリングターゲットの製造方法は、
　電解Ｎｉを加熱して溶融させ、Ｎｉの融解温度に対して１０℃以上高い温度で１０分間以上保持した後、冷却して固化してＮｉ鋳塊を得る水素低減処理工程と、
　無酸素銅と前記Ｎｉ鋳塊とを溶解鋳造してＣｕ－Ｎｉ合金鋳塊を得る溶解鋳造工程と、
　溶解鋳造工程で得られたＣｕ－Ｎｉ合金鋳塊に熱間圧延を施し、平均結晶粒径が１００μｍ以下、ビッカース硬さが６０Ｈｖ以上１２０Ｈｖ以下とされたＣｕ－Ｎｉ合金圧延板を得る熱間圧延工程と、
　前記Ｃｕ－Ｎｉ合金圧延板のスパッタ面となる表面に研削及び研磨を行い、スパッタ面の表面粗さは、最大高さＲｚで５μｍ以下となるように調整する機械加工工程とを具備する。 A method for producing a Cu—Ni alloy sputtering target according to an aspect of the present invention includes:
Electrolytic Ni is heated and melted, held for 10 minutes or more at a temperature higher than the melting temperature of Ni for 10 minutes or more, and then cooled and solidified to obtain a Ni ingot,
A melt casting step of melt-casting oxygen-free copper and the Ni ingot to obtain a Cu-Ni alloy ingot;
Hot rolling is performed on a Cu—Ni alloy ingot obtained in the melt casting process to obtain a Cu—Ni alloy rolled sheet having an average crystal grain size of 100 μm or less and a Vickers hardness of 60 Hv to 120 Hv. Process,
The surface of the Cu—Ni alloy rolled plate that is to be a sputter surface is ground and polished, and the surface roughness of the sputter surface is adjusted to a maximum height Rz of 5 μm or less.
　本発明によれば、耐候性に優れたＣｕ－Ｎｉ合金膜を成膜でき、成膜時のマイクロアーク放電の発生を抑制することができるＣｕ－Ｎｉ合金スパッタリングターゲットを提供することが可能となる。 According to the present invention, it is possible to provide a Cu—Ni alloy sputtering target capable of forming a Cu—Ni alloy film having excellent weather resistance and suppressing the occurrence of micro arc discharge during the film formation. .
　以下に、本発明の一実施形態であるＣｕ－Ｎｉ合金スパッタリングターゲットについて詳細に説明する。
　本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットは、例えば、フラットパネルディスプレイやタッチパネル等の配線膜、若しくは、ＣｕまたはＣｕ合金からなるＣｕ配線膜の上に積層される保護膜を成膜する際に使用されるものである。
　本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットの形状およびサイズは限定されず、円板状または矩形板状の平板状であってもよいし、円筒状であってもよい。ターゲットが平板状である場合には、ターゲットの一面にインジウム、インジウム－スズ合金、スズなどのハンダを介して、銅、ステンレス、あるいはチタンからなるバッキングプレートが固定されていてもよい。ターゲットが円筒状である場合には、ターゲットの内周面に、前記同様のハンダ材を介して、前記同様の材質からなる円筒状のバッキングチューブが固定されていてもよい。
　本発明の効果は、スパッタ面の面積が１０００００ｍｍ２以上とされた大型のスパッタリングターゲットであると顕著であり、さらにスパッタリングターゲットが平板状であると効果が顕著になる。前記スパッタ面とは、スパッタリングターゲットの表面のうち、プラズマが照射されてスパッタリングに使用される領域をいう。 Hereinafter, a Cu—Ni alloy sputtering target according to an embodiment of the present invention will be described in detail.
The Cu—Ni alloy sputtering target of this embodiment is used, for example, when forming a protective film laminated on a wiring film such as a flat panel display or a touch panel, or a Cu wiring film made of Cu or Cu alloy. It is what is done.
The shape and size of the Cu—Ni alloy sputtering target of the present embodiment are not limited, and may be a disk shape or a rectangular plate shape, or a cylindrical shape. When the target is flat, a backing plate made of copper, stainless steel, or titanium may be fixed to one surface of the target via solder such as indium, indium-tin alloy, or tin. When the target is cylindrical, a cylindrical backing tube made of the same material may be fixed to the inner peripheral surface of the target via the same solder material.
The effect of the present invention is remarkable when the sputtering target is a large-sized sputtering target having an area of 100000 mm 2 or more, and the effect is remarkable when the sputtering target is flat. The sputtering surface refers to a region of the surface of the sputtering target that is used for sputtering by being irradiated with plasma.
　本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットは、Ｎｉを１６質量％以上５５質量％以下の範囲で含有し、水素の含有量が５質量ｐｐｍ未満、酸素の含有量が５００質量ｐｐｍ以下とされ、残部がＣｕおよび不可避不純物からなる組成を有している。 The Cu—Ni alloy sputtering target of the present embodiment contains Ni in the range of 16 mass% to 55 mass%, the hydrogen content is less than 5 mass ppm, and the oxygen content is 500 mass ppm or less. The balance has a composition composed of Cu and inevitable impurities.
　本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットにおいては、最大径が２μｍ以上のボイドの数が、スパッタ面内の１ｍｍ２の領域あたり１個以下とされている。ボイドの数の具体的な測定方法は、後述する。
　さらに、本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットにおいては、不可避不純物のうち炭素の含有量が５００質量ｐｐｍ以下とされている。 In the Cu—Ni alloy sputtering target of this embodiment, the number of voids having a maximum diameter of 2 μm or more is set to 1 or less per 1 mm 2 region in the sputtering surface. A specific method for measuring the number of voids will be described later.
Furthermore, in the Cu—Ni alloy sputtering target of this embodiment, the carbon content of the inevitable impurities is set to 500 mass ppm or less.
　次に、本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットの組成およびボイドの数を上述のように規定した理由について説明する。 Next, the reason why the composition and the number of voids of the Cu—Ni alloy sputtering target of this embodiment are specified as described above will be described.
（Ｎｉの含有量：１６質量％以上５５質量％以下）
　ＮｉはＣｕの耐候性を改善する作用効果を有する元素である。Ｎｉを含有することにより、成膜されたＣｕ－Ｎｉ合金膜の変色を抑制することが可能となる。
　Ｎｉの含有量が１６質量％未満の場合には、耐候性が十分に向上せず、成膜されたＣｕ－Ｎｉ合金膜の変色を十分に抑制できないおそれがある。一方、Ｎｉの含有量が５５質量％を超える場合には磁性が強くなりすぎて、スパッタ成膜が困難となるおそれがある。このような理由から、本実施形態においては、Ｎｉの含有量を１６質量％以上５５質量％以下の範囲内に設定している。Ｃｕの耐候性を確実に改善するためには、Ｎｉの含有量を２０質量％以上５０質量％以下の範囲とすることが好ましく、２５質量％以上４５質量％以下の範囲とすることがさらに好ましい。 (Ni content: 16 mass% or more and 55 mass% or less)
Ni is an element having an effect of improving the weather resistance of Cu. By containing Ni, discoloration of the formed Cu—Ni alloy film can be suppressed.
When the Ni content is less than 16% by mass, the weather resistance is not sufficiently improved, and the discoloration of the formed Cu—Ni alloy film may not be sufficiently suppressed. On the other hand, when the Ni content exceeds 55% by mass, the magnetism becomes too strong, and it may be difficult to form a sputter film. For this reason, in the present embodiment, the Ni content is set in the range of 16 mass% to 55 mass%. In order to reliably improve the weather resistance of Cu, the Ni content is preferably in the range of 20% by mass to 50% by mass, and more preferably in the range of 25% by mass to 45% by mass. .
（水素の含有量：５質量ｐｐｍ未満）
　水素は、主としてＣｕ－Ｎｉ合金スパッタリングターゲットの製造原料に含まれていたものが、残存したものと推測される。Ｃｕ－Ｎｉ合金スパッタリングターゲットの水素の含有量はボイドの数と相関し、水素含有量が少ないとボイド数も少なくなる傾向があることが本発明者らの研究で判明した。また、ボイドが存在するとその周囲のＣｕ－Ｎｉ合金部に電荷が溜まりやすいことから、ボイドの数が多くなると、スパッタ成膜時において、ボイドの周囲に電荷が溜まってマイクロアーク放電の発生回数が増大するおそれがあることが本発明者らの研究で判明した。このような理由から、本実施形態においては、水素の含有量を５質量ｐｐｍ未満に設定している。 (Hydrogen content: less than 5 ppm by mass)
It is presumed that hydrogen was mainly contained in the raw material for producing the Cu—Ni alloy sputtering target. It has been found by the present inventors that the hydrogen content of the Cu—Ni alloy sputtering target correlates with the number of voids, and that the number of voids tends to decrease when the hydrogen content is small. In addition, when voids exist, electric charges easily accumulate in the surrounding Cu—Ni alloy part. Therefore, when the number of voids increases, electric charges accumulate around the voids during sputter film formation, and the number of occurrences of micro arc discharge is reduced. Our study has shown that there is a risk of an increase. For this reason, in this embodiment, the hydrogen content is set to less than 5 ppm by mass.
　マイクロアーク放電を確実に抑制し、安定してスパッタ成膜するためには、水素の含有量を４質量ｐｐｍ未満とすることが好ましく、３質量ｐｐｍ未満とすることがさらに好ましい。水素含有量の下限は、通常は０．１質量ｐｐｍ以上である。水素含有量を０．１質量ｐｐｍ未満としてもボイド数を減少させる効果は向上せず、却って、水素含有量を低減させるための作業が煩雑になり、生産コストが高くなるおそれがある。 In order to reliably suppress micro arc discharge and stably form a sputter film, the hydrogen content is preferably less than 4 ppm by mass, and more preferably less than 3 ppm by mass. The lower limit of the hydrogen content is usually 0.1 mass ppm or more. Even if the hydrogen content is less than 0.1 mass ppm, the effect of reducing the number of voids is not improved. On the other hand, the work for reducing the hydrogen content becomes complicated and the production cost may increase.
（酸素の含有量：５００質量ｐｐｍ以下）
　酸素は、Ｃｕ－Ｎｉ合金スパッタリングターゲットを構成するＣｕおよびＮｉの酸化物やターゲットの溶解鋳造時に溶解炉の耐火物の一部が鋳塊中に巻き込まれて残存した酸化物として存在するものと推測される。これらの酸化物は二次電子を放出しやすいことから、Ｃｕ－Ｎｉ合金スパッタリングターゲット中の酸化物の含有量が多くなりすぎると、スパッタ成膜時において、二次電子の放出量が増加して、マイクロアーク放電の発生回数が増大するおそれがあることが本発明者らの研究で判明した。このような理由から、本実施形態においては、酸素の含有量を５００質量ｐｐｍ以下に設定している。 (Oxygen content: 500 mass ppm or less)
It is assumed that oxygen is present as the oxide that remains when a part of the refractory of the melting furnace is caught in the ingot during melting and casting of the Cu and Ni oxides and the target constituting the Cu—Ni alloy sputtering target. Is done. Since these oxides easily emit secondary electrons, if the content of oxide in the Cu—Ni alloy sputtering target is excessive, the amount of secondary electrons emitted increases during sputtering film formation. The present inventors have found that the number of occurrences of micro arc discharge may increase. For this reason, in this embodiment, the oxygen content is set to 500 mass ppm or less.
　マイクロアーク放電を確実に抑制し、安定してスパッタ成膜するためには、酸素の含有量を３００質量ｐｐｍ以下とすることが好ましく、５０質量ｐｐｍ以下とすることがさらに好ましい。酸素含有量の下限は、通常は０．１質量ｐｐｍ以上である。酸素含有量を０．１質量ｐｐｍ未満としても二次電子の放出量を減少させる効果は向上せず、却って、酸素含有量を低減させるための作業が煩雑になり、生産コストが高くなるおそれがある。 In order to reliably suppress micro arc discharge and stably form a sputter film, the oxygen content is preferably 300 ppm by mass or less, and more preferably 50 ppm by mass or less. The lower limit of the oxygen content is usually 0.1 mass ppm or more. Even if the oxygen content is less than 0.1 mass ppm, the effect of reducing the emission amount of secondary electrons is not improved. On the other hand, the work for reducing the oxygen content becomes complicated and the production cost may increase. is there.
（炭素の含有量：５００質量ｐｐｍ以下）
　炭素は、本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットの製造工程において割れの発生原因となるおそれがある元素である。割れはＣｕ－Ｎｉ合金の圧延時に、Ｃｕ－Ｎｉ合金圧延板の外周から進行する。微細な割れであれば機械加工などによって除去できるが、炭素の含有量が５００ｐｐｍを超えると割れが大きくなる傾向が現われ、機械加工によっては、割れを完全に除去することが困難となるおそれがあることが本発明者らの研究で判明した。Ｃｕ－Ｎｉ合金スパッタリングターゲット中に割れが存在すると、スパッタ成膜時において、割れを起点とするマイクロアーク放電の発生回数が増大するおそれがある。すなわち炭素の含有量が少ないことは、スパッタ成膜時にマイクロアーク放電発生の原因の一つとなる割れの発生量が少ないことを意味することが本発明者らの研究で判明した。このような理由から、本実施形態においては、炭素の含有量を５００質量ｐｐｍ以下に設定している。 (Carbon content: 500 mass ppm or less)
Carbon is an element that may cause cracking in the manufacturing process of the Cu—Ni alloy sputtering target of the present embodiment. Cracking proceeds from the outer periphery of the rolled Cu—Ni alloy sheet during rolling of the Cu—Ni alloy. If it is a fine crack, it can be removed by machining or the like, but if the carbon content exceeds 500 ppm, the crack tends to increase, and depending on the machining, it may be difficult to completely remove the crack. This has been found by the inventors' research. If cracks exist in the Cu—Ni alloy sputtering target, the number of occurrences of micro arc discharge starting from the cracks may increase during sputtering film formation. That is, it has been found by the present inventors that the low carbon content means that the amount of cracks that causes micro arc discharge during sputtering film formation is small. For this reason, in this embodiment, the carbon content is set to 500 mass ppm or less.
　割れの発生を確実に抑制し、スパッタ成膜時のマイクロアーク放電の発生を抑えるためには、炭素の含有量を３００質量ｐｐｍ以下とすることが好ましく、５０質量ｐｐｍ以下とすることがさらに好ましい。炭素含有量の下限は、通常は３質量ｐｐｍ以上である。炭素含有量を３質量ｐｐｍ未満としても微細な割れを減少させる効果は向上せず、却って、炭素含有量を低減させるための作業が煩雑になり、生産コストが高くなるおそれがある。 In order to reliably suppress the occurrence of cracks and suppress the occurrence of micro arc discharge during sputtering film formation, the carbon content is preferably 300 mass ppm or less, and more preferably 50 mass ppm or less. . The lower limit of the carbon content is usually 3 ppm by mass or more. Even if the carbon content is less than 3 ppm by mass, the effect of reducing fine cracks is not improved. On the other hand, the work for reducing the carbon content becomes complicated and the production cost may increase.
（ボイドの数）
　本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットにおいて、スパッタ面に最大径が２μｍ以上のボイドが存在していると、ボイドの周囲に電荷が集中してマイクロアーク放電が発生しやすくなるおそれがあることが本発明者らの研究で判明した。このような理由から、本実施形態においては、最大径が２μｍ以上のボイドの数をスパッタ面内の１ｍｍ２の領域あたり１個以下に制限している。ボイドの数の具体的な測定方法は、後述する。 (Number of voids)
In the Cu—Ni alloy sputtering target of the present embodiment, if a void having a maximum diameter of 2 μm or more exists on the sputtering surface, there is a possibility that electric charge is concentrated around the void and micro arc discharge is likely to occur. Was found by the inventors' research. For this reason, in this embodiment, the number of voids having a maximum diameter of 2 μm or more is limited to one or less per 1 mm 2 region in the sputtering surface. A specific method for measuring the number of voids will be described later.
　次に、本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットを製造する方法の一例について説明する。
　本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットは、溶解鋳造工程、熱間圧延工程、（レベラー加工工程／冷間圧延工程、熱処理工程）、機械加工工程、といった工程を経て製造される。以下に、各工程について説明する。 Next, an example of a method for producing the Cu—Ni alloy sputtering target of this embodiment will be described.
The Cu—Ni alloy sputtering target of this embodiment is manufactured through processes such as a melt casting process, a hot rolling process, (leveler processing process / cold rolling process, heat treatment process), and a machining process. Below, each process is demonstrated.
（溶解鋳造工程）
　溶解鋳造工程では、ＣｕとＮｉとを溶解鋳造してＣｕ－Ｎｉ合金鋳塊を得る。
　まず、上述のターゲット組成となるように、溶解原料を秤量する。溶解原料としては、純度９９．９９質量％以上のＣｕと純度９９．９質量％以上のＮｉを用いることが好ましい。Ｃｕの溶解原料としては、酸素濃度が１０質量ｐｐｍ以下に規定されて純度９９．９９質量％以上とされた無酸素銅を用いることが好ましい。 (Melting casting process)
In the melt casting process, Cu and Ni are melt cast to obtain a Cu—Ni alloy ingot.
First, the melting raw material is weighed so that the above-described target composition is obtained. As a melting raw material, it is preferable to use Cu having a purity of 99.99% by mass or more and Ni having a purity of 99.9% by mass or more. As a raw material for dissolving Cu, oxygen-free copper having an oxygen concentration of 10 mass ppm or less and a purity of 99.99 mass% or more is preferably used.
　Ｎｉの溶解原料としては、電解法によって精製された電解Ｎｉに水素低減処理を行ったものを用いることが好ましい。
　水素低減処理を行うのは、通常、電解Ｎｉは水素を１０質量ｐｐｍを超えて含有しているので、そのまま溶解原料として用いると、電解Ｎｉ中の水素がＣｕ－Ｎｉ合金鋳塊に残存してボイドを発生させるおそれがあるからである。Ｃｕ－Ｎｉ合金鋳塊中にボイドが発生すると、そのボイドがターゲットに残留して、スパッタ成膜時にマイクロアーク放電を生じさせる要因となるおそれがある。 As a Ni melting material, it is preferable to use a material obtained by subjecting electrolytic Ni purified by an electrolytic method to a hydrogen reduction treatment.
The hydrogen reduction treatment is usually performed because electrolytic Ni contains more than 10 ppm by mass of hydrogen, so when used as a raw material for dissolution, hydrogen in electrolytic Ni remains in the Cu—Ni alloy ingot. This is because voids may be generated. If voids are generated in the Cu—Ni alloy ingot, the voids may remain on the target and cause micro arc discharge during sputtering film formation.
　電解Ｎｉ中の水素によってＣｕ－Ｎｉ合金鋳塊にボイドが発生する機構は、次のように考えられる。電解Ｎｉは溶解度以上の過剰の水素を含有するため、Ｃｕと電解Ｎｉとを溶解させてＣｕ－Ｎｉ合金の溶湯を生成させると、電解Ｎｉ中の水素はＣｕ－Ｎｉ合金の溶湯（液相）に溶け込む。一方、水素はＣｕ－Ｎｉ合金の固相への溶解度が低いため、Ｃｕ－Ｎｉ合金の溶湯が凝固するときに、液相と固相の境界で水素ガスの気泡が発生する。溶湯の凝固と気泡の発生は同時に進行し、溶湯の外部に排出されなかった気泡がボイドとしてＣｕ－Ｎｉ合金鋳塊に取り残される。 The mechanism by which voids are generated in the Cu—Ni alloy ingot by hydrogen in electrolytic Ni is considered as follows. Electrolytic Ni contains excess hydrogen above its solubility. Therefore, when Cu and electrolytic Ni are dissolved to form a molten Cu—Ni alloy, the hydrogen in electrolytic Ni is the molten Cu—Ni alloy (liquid phase). Blend into. On the other hand, since hydrogen has a low solubility in the solid phase of the Cu—Ni alloy, hydrogen gas bubbles are generated at the boundary between the liquid phase and the solid phase when the melt of the Cu—Ni alloy solidifies. The solidification of the molten metal and the generation of bubbles proceed simultaneously, and the bubbles that have not been discharged to the outside of the molten metal are left as voids in the Cu—Ni alloy ingot.
　電解Ｎｉの水素低減処理としては、電解Ｎｉを加熱して溶融させ、Ｎｉの融解温度に対して１０℃～５０℃高い温度で２分～３０分間保持した後、冷却して固化してＮｉ鋳塊を得る方法を用いることができる。より好ましくは、Ｎｉの融解温度に対して１５℃～３５℃高い温度で１０分～２０分間保持した後、冷却して固化してＮｉ鋳塊を得てもよい。 As the hydrogen reduction treatment of electrolytic Ni, electrolytic Ni is heated and melted, held at a temperature 10 to 50 ° C. higher than the melting temperature of Ni for 2 to 30 minutes, then cooled and solidified to form a Ni casting. A method of obtaining a lump can be used. More preferably, a Ni ingot may be obtained by holding at a temperature 15 ° C. to 35 ° C. higher than the melting temperature of Ni for 10 minutes to 20 minutes and then cooling to solidify.
　電解Ｎｉの水素低減処理において、加熱装置は誘導溶解炉を用いることが好ましい。水素低減処理は真空雰囲気あるいは不活性ガス雰囲気で行うことが好ましい。この水素低減処理によって得られるＮｉ鋳塊は、水素の含有量が１０質量ｐｐｍ以下、特に５質量ｐｐｍ以下であることが好ましい。製造コストの観点からは、Ｎｉ鋳塊の水素の含有量が０．１質量ｐｐｍ以上であってもよい。 In the hydrogen reduction treatment of electrolytic Ni, it is preferable to use an induction melting furnace as the heating device. The hydrogen reduction treatment is preferably performed in a vacuum atmosphere or an inert gas atmosphere. The Ni ingot obtained by this hydrogen reduction treatment preferably has a hydrogen content of 10 mass ppm or less, particularly 5 mass ppm or less. From the viewpoint of manufacturing cost, the hydrogen content of the Ni ingot may be 0.1 mass ppm or more.
　秤量したＣｕとＮｉとを溶解鋳造する際は、溶解原料を十分に混合して溶湯の組成を均一化するために、誘導溶解炉を用いることが好ましい。
　溶解時において、合金構成成分であるＣｕおよびＮｉの酸化を防止することにより、酸化物の混入の発生が抑制される。溶解時の酸化を防止するためには、真空雰囲気あるいは不活性ガス雰囲気で溶解することが好ましい。生産性を考慮して大気雰囲気で溶解する場合には、溶解原料を保持するためにカーボンるつぼを使用することや、カーボン粒子及びカーボン粉末によって湯面を被覆することによって、溶湯を還元性雰囲気に保つ方法を採用してもよい。 When melting and casting the weighed Cu and Ni, it is preferable to use an induction melting furnace in order to sufficiently mix the melting raw materials and make the composition of the molten metal uniform.
By preventing oxidation of Cu and Ni, which are alloy constituents, at the time of melting, generation of oxide is suppressed. In order to prevent oxidation during melting, it is preferable to dissolve in a vacuum atmosphere or an inert gas atmosphere. When melting in an air atmosphere in consideration of productivity, use a carbon crucible to hold the melting raw material, or cover the molten metal surface with carbon particles and carbon powder to make the molten metal into a reducing atmosphere. A method of keeping may be adopted.
　上述の合金元素の酸化を確実に防止することは工業上困難であるとともに、溶解炉の耐火材や上述のカーボン粉末等も鋳塊中に巻き込まれて非金属介在物となる可能性がある。これらの非金属介在物の巻き込みを防止するためには、縦型の連続鋳造機を用いて、タンディッシュ又はディストリビュータによって、非金属介在物を浮上分離させることが好ましい。一方向凝固法のように冷却速度を遅くして非金属介在物を浮上分離することも好ましい。 It is industrially difficult to reliably prevent oxidation of the above-described alloy elements, and there is a possibility that refractory materials for the melting furnace, the above-described carbon powder, and the like are also involved in the ingot and become nonmetallic inclusions. In order to prevent the inclusion of these nonmetallic inclusions, it is preferable to float and separate the nonmetallic inclusions by a tundish or a distributor using a vertical continuous casting machine. It is also preferable to float and separate nonmetallic inclusions by slowing the cooling rate as in the unidirectional solidification method.
（熱間圧延工程）
　熱間圧延工程では、溶解鋳造工程で得られたＣｕ－Ｎｉ合金鋳塊を、所定の長さに切断した後、熱間圧延を施す。
　熱間圧延の条件は、１パス当たりの圧下率が１０％以上２０％以下で、熱間圧延温度が５５０℃以上１０００℃以下とされていることが好ましい。より好ましくは、１パス当たりの圧下率が１１％以上１７％以下で、熱間圧延温度が８００℃以上１０００℃以下である。圧下率は、下記の式より算出される値である。
　圧下率（％）＝｛（熱間圧延パス前のＣｕ－Ｎｉ合金の厚さ－熱間圧延パス後のＣｕ－Ｎｉ合金の厚さ）／熱間圧延パス前のＣｕ－Ｎｉ合金の厚さ｝×１００
　熱間圧延工程の全体としての圧下率は、５０％以上かつ９０％以下であることが好ましく、より好ましくは熱間圧延工程の全体としての圧下率は、６０％以上かつ８０％以下である。 (Hot rolling process)
In the hot rolling process, the Cu—Ni alloy ingot obtained in the melt casting process is cut into a predetermined length and then hot rolled.
The conditions for hot rolling are preferably a rolling reduction per pass of 10% to 20% and a hot rolling temperature of 550 ° C to 1000 ° C. More preferably, the rolling reduction per pass is 11% to 17%, and the hot rolling temperature is 800 ° C to 1000 ° C. The rolling reduction is a value calculated from the following equation.
Reduction ratio (%) = {(Cu—Ni alloy thickness before hot rolling pass−Cu—Ni alloy thickness after hot rolling pass) / Cu—Ni alloy thickness before hot rolling pass } × 100
The overall rolling reduction in the hot rolling process is preferably 50% or more and 90% or less, and more preferably, the overall rolling reduction in the hot rolling process is 60% or more and 80% or less.
　熱間圧延工程により、平均結晶粒径が１００μｍ以下、ビッカース硬さが６０Ｈｖ以上１２０Ｈｖ以下とされたＣｕ－Ｎｉ合金圧延板を得ることができる。より好ましくは、平均結晶粒径が５μｍ以上かつ５０μｍ以下、ビッカース硬さが８０Ｈｖ以上１１０Ｈｖ以下とされてもよい。 By a hot rolling process, a Cu—Ni alloy rolled sheet having an average crystal grain size of 100 μm or less and a Vickers hardness of 60 Hv to 120 Hv can be obtained. More preferably, the average crystal grain size may be 5 μm or more and 50 μm or less, and the Vickers hardness may be 80 Hv or more and 110 Hv or less.
（レベラー加工工程／冷間圧延工程、熱処理工程）
　上述の熱間圧延工程で得られたＣｕ－Ｎｉ合金圧延板は、その圧延板の平面度を向上させるためにレベラー加工又は冷間圧延加工を実施してもよい。
　レベラー加工又は冷間圧延加工を行った場合には、平均結晶粒径及びビッカース硬さを調整するために、５５０℃以上８５０℃以下の温度で１～２時間保持する条件で熱処理を行い、その後、大気中で放冷することが好ましい。より好ましくは、６５０℃以上８５０℃以下の温度で１時間～２時間保持する条件で熱処理を行い、その後、大気中で放冷してもよい。 (Leveler processing process / cold rolling process, heat treatment process)
The Cu—Ni alloy rolled sheet obtained in the hot rolling process described above may be subjected to a leveler process or a cold rolling process in order to improve the flatness of the rolled sheet.
When leveler processing or cold rolling processing is performed, in order to adjust the average crystal grain size and Vickers hardness, heat treatment is performed at a temperature of 550 ° C. to 850 ° C. for 1 to 2 hours. It is preferable to cool in the atmosphere. More preferably, the heat treatment may be performed under the condition of holding at a temperature of 650 ° C. or higher and 850 ° C. or lower for 1 to 2 hours, and then allowed to cool in the air.
（機械加工工程）
　機械加工工程では、上述のようにして得られたＣｕ－Ｎｉ合金圧延板のスパッタ面となる表面に研削及び研磨を行う。スパッタ面の表面粗さは、最大高さＲｚで５μｍ以下となるように調整することが好ましい。より好ましくは、スパッタ面の表面粗さは、最大高さＲｚで０．５μｍ以上かつ３μｍ以下となるように調整してもよい。 (Machining process)
In the machining step, grinding and polishing are performed on the surface to be the sputtered surface of the Cu—Ni alloy rolled plate obtained as described above. It is preferable to adjust the surface roughness of the sputter surface so that the maximum height Rz is 5 μm or less. More preferably, the surface roughness of the sputter surface may be adjusted to be 0.5 μm or more and 3 μm or less at the maximum height Rz.
　以上のような工程により、本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットが製造される。
　このＣｕ－Ｎｉ合金スパッタリングターゲットは、必要に応じてＣｕ製のバッキングプレートに半田付けまたはろう付けされて、スパッタ装置に取り付けられ、対向配置された基板上にＣｕ－Ｎｉ合金膜をスパッタ成膜する。
　スパッタ成膜されたＣｕ－Ｎｉ合金膜は、上述したＣｕ－Ｎｉ合金スパッタリングターゲットと同等の組成を有することになる。 The Cu—Ni alloy sputtering target of the present embodiment is manufactured through the processes as described above.
This Cu—Ni alloy sputtering target is soldered or brazed to a Cu backing plate as necessary, and is attached to a sputtering apparatus, and a Cu—Ni alloy film is formed on the opposing substrate by sputtering. .
The sputtered Cu—Ni alloy film has the same composition as the above-described Cu—Ni alloy sputtering target.
　本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットによれば、成分がＣｕとＮｉの二元素であるため、組成のばらつきが小さくなる。Ｎｉの含有量が１６質量％以上５５質量％以下の範囲とされているので、成膜されたＣｕ－Ｎｉ合金膜の耐候性が高くなる。 According to the Cu—Ni alloy sputtering target of this embodiment, since the components are two elements of Cu and Ni, the variation in composition is reduced. Since the Ni content is in the range of 16 mass% or more and 55 mass% or less, the weather resistance of the formed Cu—Ni alloy film becomes high.
　さらに、水素の含有量が５質量ｐｐｍ未満で、酸素の含有量が５００質量ｐｐｍ以下と制限されており、ボイドや酸化物の混入量が少ないので、スパッタ成膜時において、ボイドや酸化物によってマイクロアーク放電が発生することを抑制でき、スパッタ成膜を安定して行うことが可能となる。 Furthermore, the hydrogen content is less than 5 ppm by mass, the oxygen content is limited to 500 ppm by mass or less, and the amount of voids and oxides mixed is small. Generation of micro arc discharge can be suppressed, and sputtering film formation can be performed stably.
　本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットにおいては、最大径が２μｍ以上のボイドの数が、スパッタ面内の１ｍｍ２の領域あたり１個以下であるとされているので、スパッタ成膜時におけるマイクロアーク放電の発生をより確実に抑制することができる。 In the Cu—Ni alloy sputtering target of the present embodiment, the number of voids having a maximum diameter of 2 μm or more is 1 or less per 1 mm 2 region in the sputtering surface. The occurrence of arc discharge can be more reliably suppressed.
　また、本実施形態のＣｕ－Ｎｉ合金スパッタリングターゲットにおいては、前記不可避不純物のうち炭素の含有量が５００質量ｐｐｍ以下とされているので、熱間圧延性を向上させることができ、熱間圧延時の割れの発生を抑制することができる。 Further, in the Cu—Ni alloy sputtering target of the present embodiment, since the carbon content of the inevitable impurities is 500 mass ppm or less, the hot rolling property can be improved, and during hot rolling, The occurrence of cracks can be suppressed.
　以上、本発明の実施形態について説明したが、本発明はこれに限定されることはなく、その発明の技術的思想を逸脱しない範囲で適宜変更可能である。
　例えば、本実施形態では、平板状をなし、そのスパッタ面の面積が１０００００ｍｍ２以上とされた大型のスパッタリングターゲットとして説明したが、Ｃｕ－Ｎｉ合金スパッタリングターゲットの形状に特に限定はなく、円板状あるいは矩形平板状をなしていてもよいし、円筒形状をなしていてもよい。スパッタ面の面積についても上述の範囲に限定されることはない。いずれの場合も本発明の効果は得ることができる。 As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, in the present embodiment, a large sputtering target having a flat plate shape and an area of the sputtering surface of 100,000 mm 2 or more has been described. However, the shape of the Cu—Ni alloy sputtering target is not particularly limited, and is a disk shape. Alternatively, it may have a rectangular flat plate shape or a cylindrical shape. The area of the sputter surface is not limited to the above range. In either case, the effects of the present invention can be obtained.
　以下に、本発明に係るＣｕ－Ｎｉ合金スパッタリングターゲットの作用効果について評価した評価試験の結果を説明する。 Hereinafter, the results of an evaluation test for evaluating the function and effect of the Cu—Ni alloy sputtering target according to the present invention will be described.
［本発明例１～８、比較例１～４］
（１）電解Ｎｉの水素低減処理（水素低減Ｎｉ鋳塊の製造）
　電解Ｎｉ（純度：９９．９９質量％以上）を用意した。電解Ｎｉ中の水素含有量は１１～１５質量ｐｐｍの範囲であった。
　電解Ｎｉをアルミナるつぼに投入した。次いで、高周波誘導加熱炉を用いて真空雰囲気中で、電解Ｎｉを加熱して溶融させ、Ｎｉの融解温度に対して１０℃～５０℃高い温度で２～１５分間保持した後、冷却して固化して、水素低減Ｎｉ鋳塊を得た。水素低減処理持の溶融保持時間と得られた水素低減Ｎｉ鋳塊の水素含有量を、表１に示す。ただし、比較例１では電解Ｎｉの水素低減処理は行わなかった。電解Ｎｉおよび水素低減Ｎｉ鋳塊の水素含有量は、不活性ガス融解－熱伝導度法（ＪＩＳＺ２６１４）によって分析した。 [Invention Examples 1 to 8, Comparative Examples 1 to 4]
(1) Hydrogen reduction treatment of electrolytic Ni (production of hydrogen reduced Ni ingot)
Electrolytic Ni (purity: 99.99% by mass or more) was prepared. The hydrogen content in the electrolytic Ni was in the range of 11 to 15 ppm by mass.
Electrolytic Ni was put into an alumina crucible. Next, electrolytic Ni is heated and melted in a vacuum atmosphere using a high-frequency induction heating furnace, held at a temperature 10 to 50 ° C. higher than the melting temperature of Ni for 2 to 15 minutes, and then cooled and solidified. Thus, a hydrogen reduced Ni ingot was obtained. Table 1 shows the melt retention time of the hydrogen reduction treatment and the hydrogen content of the obtained hydrogen reduced Ni ingot. However, in Comparative Example 1, the hydrogen reduction treatment of electrolytic Ni was not performed. The hydrogen content of the electrolytic Ni and hydrogen reduced Ni ingots was analyzed by an inert gas melting-thermal conductivity method (JISZ2614).
（２）Ｃｕ－Ｎｉ合金鋳塊の製造
　上記（１）で得られた水素低減Ｎｉ鋳塊と、無酸素銅（純度：９９．９９質量％）とを、下記の表１に示す組成となるように、表１に示す溶解るつぼに投入した。ただし、比較例１ではＮｉ原料として水素含有量が１１ｐｐｍの電解Ｎｉをそのまま用いた。次いで、高周波誘導加熱炉を用いて、下記の表１に示す雰囲気中で加熱して、得られた溶湯を、ディストリビュータによって縦型の連続鋳造機に注湯し、１８０ｍｍ×６０ｍｍの矩形断面を有する鋳塊を製造した。この鋳塊のトップ部及びボトム部を切断除去した後、熱間圧延に適した長さに切断し、１８０ｍｍ×６０ｍｍ×長さ６００ｍｍのＣｕ－Ｎｉ合金鋳塊を得た。 (2) Production of Cu—Ni alloy ingot The hydrogen-reduced Ni ingot obtained in (1) above and oxygen-free copper (purity: 99.99 mass%) have the composition shown in Table 1 below. Thus, it put into the melting crucible shown in Table 1. However, in Comparative Example 1, electrolytic Ni having a hydrogen content of 11 ppm was used as the Ni raw material. Next, using a high frequency induction heating furnace, heating is performed in the atmosphere shown in Table 1 below, and the obtained molten metal is poured into a vertical continuous casting machine by a distributor and has a rectangular cross section of 180 mm × 60 mm. An ingot was produced. After cutting and removing the top portion and the bottom portion of the ingot, the ingot was cut into a length suitable for hot rolling to obtain a Cu—Ni alloy ingot of 180 mm × 60 mm × length 600 mm.
（３）Ｃｕ－Ｎｉ合金圧延板の製造
　上記（２）で得られたＣｕ－Ｎｉ合金鋳塊を８５０℃で１時間加熱した後、１パスの圧下率を１１～１５％として熱間圧延を実施し、１９０ｍｍ×１９００ｍｍ×厚さ１８ｍｍのＣｕ－Ｎｉ合金圧延板を得た。それぞれ最終熱間圧延パス後の圧延板の温度は６００～７００℃であった。
　本発明例７においては、Ｃｕ－Ｎｉ合金圧延板の一部に目視で確認できるサイズの割れが生じていた。 (3) Manufacture of Cu—Ni alloy rolled plate After heating the Cu—Ni alloy ingot obtained in (2) above at 850 ° C. for 1 hour, hot rolling was performed with a rolling reduction of 1 pass of 11 to 15%. As a result, a rolled Cu—Ni alloy sheet having a size of 190 mm × 1900 mm × 18 mm thick was obtained. The temperature of the rolled plate after the final hot rolling pass was 600 to 700 ° C., respectively.
In Example 7 of the present invention, a crack having a size that can be visually confirmed occurred in a part of the rolled Cu—Ni alloy sheet.
（４）評価用ターゲットの製造
　得られたＣｕ－Ｎｉ合金圧延板から、マシニングセンターおよび旋盤を用いて直径１２５ｍｍ、厚さ５ｍｍの円板状のターゲット材を削り出した。得られたＣｕ－Ｎｉ合金スパッタリングターゲットを、直径１４５ｍｍ、厚さ５ｍｍの円板状のＣｕ製のバッキングプレートにはんだ付けした後、さらにスパッタ面に研磨加工を行って評価用ターゲットを得た。研磨加工は使用すると粒を粗目（＃１５０）から順に細目（＃８００）まで変えて研磨することにより表面粗さをＲＺ：３μｍまで低減した後、研磨で付着した粉じんをエタノールで洗浄して除去した。
　本発明例７においては、ターゲット材の削り出しの際に、Ｃｕ－Ｎｉ合金圧延板の割れ部分は除去した。 (4) Production of target for evaluation A disk-shaped target material having a diameter of 125 mm and a thickness of 5 mm was cut out from the obtained rolled Cu—Ni alloy plate using a machining center and a lathe. The obtained Cu—Ni alloy sputtering target was soldered to a disk-shaped Cu backing plate having a diameter of 145 mm and a thickness of 5 mm, and the sputtering surface was further polished to obtain an evaluation target. When polishing is used, the grain is changed from coarse (# 150) to fine (# 800) in order to reduce the surface roughness to RZ: 3 μm, and then the dust adhering to the polishing is removed by washing with ethanol. did.
In Example 7 of the present invention, when the target material was cut out, the cracked portion of the rolled Cu—Ni alloy plate was removed.
（５）評価
　このようにして得られた評価用ターゲットについて、不可避不純物（水素、酸素、炭素）の含有量、ボイドの数、マイクロアーク放電回数（異常放電回数）および膜の耐候性を、以下のようにして評価した。 (5) Evaluation For the target for evaluation thus obtained, the content of inevitable impurities (hydrogen, oxygen, carbon), the number of voids, the number of micro arc discharges (number of abnormal discharges), and the weather resistance of the film are as follows: It evaluated as follows.
（水素、酸素、および炭素の含有量）
　水素含有量はＣｕ－Ｎｉ圧延板を切断して採取したサンプル小片を用いて、不活性ガス融解－熱伝導度法によって分析した。酸素および炭素は同様に採取したサンプル小片を用いて、ＪＩＳＺ２６１３に規定される赤外線吸収法によって分析した。 (Hydrogen, oxygen, and carbon content)
The hydrogen content was analyzed by inert gas melting-thermal conductivity method using a sample piece taken by cutting a Cu—Ni rolled sheet. Oxygen and carbon were analyzed by an infrared absorption method defined in JISZ2613 using sample pieces collected in the same manner.
（ボイドの数）
　ボイドの数は下記の方法により測定した。なお、本明細書におけるボイドの数は、いずれも下記の方法によって計測した値とする。
　評価用ターゲットのスパッタ面を均等に４等分し、それぞれの部分から組織観察用のサンプルを切り出した。これら４つのサンプルのスパッタ面を、＃１８０から＃２４００までの研磨紙を用いて、粗目から細目まで順に研磨紙を変えて研磨した後、平均粒径１μｍの研磨材を用いて仕上げ研磨した。この研磨方法によれば、表面粗さは概ねＲａ：０．１μｍ未満となる。次いで、研磨した４つのサンプルのスパッタ面から、０．５ｍｍ×０．５ｍｍ（＝０．２５ｍｍ２）の領域をそれぞれ無作為に１つずつ選択し、各領域を光学顕微鏡により倍率１００倍の暗視野像として観察した。暗視野像であるため、スパッタ面に一定のサイズ以上のボイド（凹み）が存在するとその部分は白く光る点として検出される。各領域内において、ボイドの最大部の長さが２μｍ以上であるボイドの個数を計数した。４個の領域を合計した１ｍｍ２内において検出されたボイドの個数が１個または０個であったものを「ＯＫ」とし、２個以上のものを「ＮＧ」として評価した。その評価結果を、表２に示す。 (Number of voids)
The number of voids was measured by the following method. Note that the number of voids in this specification is a value measured by the following method.
The sputter surface of the evaluation target was equally divided into four equal parts, and samples for tissue observation were cut out from the respective portions. The sputter surfaces of these four samples were polished using # 180 to # 2400 polishing paper in order from coarse to fine, and then polished with an abrasive having an average particle size of 1 μm. According to this polishing method, the surface roughness is approximately Ra: less than 0.1 μm. Next, each region of 0.5 mm × 0.5 mm (= 0.25 mm 2 ) was randomly selected from the four sputtered surfaces of the polished samples, and each region was darkened at a magnification of 100 times with an optical microscope. It was observed as a field image. Since this is a dark field image, if there is a void (dent) of a certain size or more on the sputter surface, that portion is detected as a point that shines white. In each region, the number of voids having a maximum length of 2 μm or more was counted. Evaluation was made with “OK” when the number of voids detected within 1 mm 2 totaling 4 regions was 1 or 0, and “NG” when 2 or more. The evaluation results are shown in Table 2.
（マイクロアーク放電回数）
　評価用ターゲットをスパッタ装置に取り付け、到達真空度：５×１０－４Ｐａ、ガス圧：アルゴン０．３Ｐａ、スパッタ電力：直流１０００Ｗの条件で使用開始から３０分間のプレスパッタを行った後、マイクロアーク放電の回数を調べた。マイクロアーク放電は、（株）ランドマークテクノロジー社製のマイクロアークモニターをスパッタ電源に付加して、放電電圧の低下を検出することにより検出した。実際の操業形態である断続的なスパッタ成膜を模して１分間の放電と１分間の停止を５０回繰り返し行い、積算して検出されたアーク放電のエネルギーが５０ＭＪ以下であるマイクロアーク放電回数を計数した。マイクロアーク放電回数の計数結果を、表２に示す。 (Number of micro arc discharges)
A target for evaluation was attached to the sputtering apparatus, pre-sputtering was performed for 30 minutes from the start of use under the conditions of ultimate vacuum: 5 × 10 −4 Pa, gas pressure: argon 0.3 Pa, sputtering power: direct current 1000 W, then micro sputtering The number of arc discharges was examined. The micro arc discharge was detected by adding a micro arc monitor manufactured by Landmark Technology Co., Ltd. to the sputtering power source and detecting a decrease in the discharge voltage. The number of micro arc discharges in which the arc discharge energy is 50 MJ or less by repeating 50 minutes of discharge for 1 minute and stopping for 1 minute, imitating intermittent sputter deposition, which is an actual operation mode Were counted. Table 2 shows the results of counting the number of micro arc discharges.
（膜の耐候性）
　５０ｍｍ×５０ｍｍ×０．７ｍｍの無アルカリガラス基板を、評価用ターゲットと基板間距離が６０ｍｍとなるように対向配置し、到達真空度：５×１０－４Ｐａ、ガス圧：アルゴン０．３Ｐａ、スパッタ電力：直流６００Ｗの条件でスパッタを実施し、基板上に膜厚１５０ｎｍのＣｕ－Ｎｉ合金膜を形成した。
　成膜されたＣｕ－Ｎｉ合金膜に対して、温度７０℃、相対湿度９０％の恒温恒湿条件下で２５０時間保持する恒温恒湿試験を実施した後、Ｃｕ－Ｎｉ合金膜表面を目視観察し、変色が認められたものを「ＮＧ」、変色が確認できなかったものを「ＯＫ」として評価した。その評価結果を、表２に示す。 (Membrane weather resistance)
A non-alkali glass substrate of 50 mm × 50 mm × 0.7 mm was placed facing the target for evaluation so that the distance between the substrates was 60 mm, the ultimate vacuum: 5 × 10 −4 Pa, the gas pressure: argon 0.3 Pa, Sputtering power: Sputtering was performed under the condition of 600 W DC, and a Cu—Ni alloy film having a thickness of 150 nm was formed on the substrate.
The formed Cu—Ni alloy film was subjected to a constant temperature and humidity test for 250 hours under a constant temperature and humidity condition of 70 ° C. and 90% relative humidity, and then the surface of the Cu—Ni alloy film was visually observed. Then, the case where the color change was recognized was evaluated as “NG”, and the case where the color change was not confirmed was evaluated as “OK”. The evaluation results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　水素の含有量が５質量ｐｐｍ以上である比較例１においては、ボイド数が多くなり、マイクロアーク放電回数が多くなった。
　酸素の含有量が５００質量ｐｐｍを超える比較例２においては、マイクロアーク放電回数が多くなり、また成膜されたＣｕ－Ｎｉ合金膜は恒温恒湿試験後に変色し、耐候性が不十分であった。
　Ｎｉの含有量が１６質量％未満である比較例３においては、成膜されたＣｕ－Ｎｉ合金膜が恒温恒湿試験後に変色し、耐候性が不十分であった。
　Ｎｉの含有量が５５質量％を超える比較例４においては、スパッタを行うことができなかった。磁性が強くなったためと推測される。 In Comparative Example 1 in which the hydrogen content was 5 mass ppm or more, the number of voids increased and the number of micro arc discharges increased.
In Comparative Example 2 in which the oxygen content exceeds 500 ppm by mass, the number of micro arc discharges is increased, and the formed Cu—Ni alloy film is discolored after the constant temperature and humidity test, resulting in insufficient weather resistance. It was.
In Comparative Example 3 in which the Ni content was less than 16% by mass, the formed Cu—Ni alloy film was discolored after the constant temperature and humidity test, and the weather resistance was insufficient.
In Comparative Example 4 where the Ni content exceeds 55 mass%, sputtering could not be performed. It is presumed that the magnetism has become stronger.
　これに対して、Ｎｉ、水素、酸素の含有量が本発明の範囲内とされた本発明例においては、ボイド数が少なく、マイクロアーク放電回数が抑えられており、安定してスパッタ成膜することができた。また成膜されたＣｕ－Ｎｉ合金膜は耐候性に優れていた。 On the other hand, in the example of the present invention in which the contents of Ni, hydrogen, and oxygen are within the scope of the present invention, the number of voids is small, the number of micro arc discharges is suppressed, and stable sputtering film formation I was able to. Further, the formed Cu—Ni alloy film was excellent in weather resistance.
　以上のことから、本発明例によれば、耐候性に優れたＣｕ－Ｎｉ合金膜を成膜でき、成膜時のマイクロアーク放電の発生を抑制することができるＣｕ－Ｎｉ合金スパッタリングターゲットを提供できることが確認された。 From the above, according to the example of the present invention, there is provided a Cu—Ni alloy sputtering target capable of forming a Cu—Ni alloy film having excellent weather resistance and suppressing the occurrence of micro arc discharge during the film formation. It was confirmed that it was possible.
　本発明のＣｕ－Ｎｉ合金スパッタリングターゲットは、耐候性に優れたＣｕ－Ｎｉ合金膜を成膜でき、成膜時のマイクロアーク放電の発生を抑制することができるから、産業上利用可能である。 The Cu—Ni alloy sputtering target of the present invention can be used industrially because it can form a Cu—Ni alloy film having excellent weather resistance and suppress the occurrence of micro arc discharge during the film formation.

Claims (4)

  1. 　Ｎｉを１６質量％以上５５質量％以下の範囲で含有し、水素の含有量が５質量ｐｐｍ未満、酸素の含有量が５００質量ｐｐｍ以下であり、残部がＣｕおよび不可避不純物からなる組成を有することを特徴とするＣｕ－Ｎｉ合金スパッタリングターゲット。 Ni is contained in the range of 16 mass% or more and 55 mass% or less, the hydrogen content is less than 5 mass ppm, the oxygen content is 500 mass ppm or less, and the balance is composed of Cu and inevitable impurities. Cu—Ni alloy sputtering target characterized by the above.
  2. 　最大径が２μｍ以上のボイドの数が、スパッタ面内の１ｍｍ２の領域あたり１個以下であることを特徴とする請求項１に記載のＣｕ－Ｎｉ合金スパッタリングターゲット。 2. The Cu—Ni alloy sputtering target according to claim 1, wherein the number of voids having a maximum diameter of 2 μm or more is 1 or less per 1 mm 2 region in the sputtering surface.
  3. 　炭素の含有量が５００質量ｐｐｍ以下であることを特徴とする請求項１または２に記載のＣｕ－Ｎｉ合金スパッタリングターゲット。 The Cu-Ni alloy sputtering target according to claim 1 or 2, wherein the carbon content is 500 mass ppm or less.
  4. 　電解Ｎｉを加熱して溶融させ、Ｎｉの融解温度に対して１０℃以上高い温度で１０分間以上保持した後、冷却して固化してＮｉ鋳塊を得る水素低減処理工程と、
    　無酸素銅と前記Ｎｉ鋳塊とを溶解鋳造してＣｕ－Ｎｉ合金鋳塊を得る溶解鋳造工程と、
    　溶解鋳造工程で得られたＣｕ－Ｎｉ合金鋳塊に熱間圧延を施し、平均結晶粒径が１００μｍ以下、ビッカース硬さが６０Ｈｖ以上１２０Ｈｖ以下とされたＣｕ－Ｎｉ合金圧延板を得る熱間圧延工程と、
    　前記Ｃｕ－Ｎｉ合金圧延板のスパッタ面となる表面に研削及び研磨を行い、スパッタ面の表面粗さは、最大高さＲｚで５μｍ以下となるように調整する機械加工工程とを具備するＣｕ－Ｎｉ合金スパッタリングターゲットの製造方法。     Electrolytic Ni is heated and melted, held for 10 minutes or more at a temperature higher than the melting temperature of Ni for 10 minutes or more, and then cooled and solidified to obtain a Ni ingot,
    A melt casting step of melt-casting oxygen-free copper and the Ni ingot to obtain a Cu-Ni alloy ingot;
    Hot rolling is performed on a Cu—Ni alloy ingot obtained in the melt casting process to obtain a Cu—Ni alloy rolled sheet having an average crystal grain size of 100 μm or less and a Vickers hardness of 60 Hv to 120 Hv. Process,
    A Cu-Ni alloy rolling plate having a machining step of grinding and polishing the surface to be a sputter surface of the Cu-Ni alloy rolled plate, and adjusting the surface roughness of the sputter surface to a maximum height Rz of 5 μm or less. Manufacturing method of Ni alloy sputtering target.
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