Ni alloy film and sputtering target material for forming Ni alloy film

Abstract

Provided are a Ni alloy film having high oxidation resistance at high temperatures even without containing Cr, and a sputtering target material for forming the Ni alloy film. The Ni alloy film contains 9.0 to 25.0 at% of Al and 1.0 to 8.0 at% of V, with the remainder comprising Ni and unavoidable impurities, the total content of Al and V is preferably 11.0 to 30.0 at%, the content of Al is preferably 10.0 to 18.0 at%, and the Ni alloy film may be formed from a sputtering target material containing the same composition and having a Curie point of not more than normal temperature.

Description

Technical Field

[0001] The present invention relates to a Ni alloy film having high-temperature oxidation resistance and a sputtering target for forming the same. The Ni alloy film is used for a protective film for internal electrodes of electronic parts that require oxidation resistance at high temperatures, for example, an anti-oxidation film for device components used in semiconductor manufacturing equipment or calcining furnaces, etc. Background Art

[0002] In recent years, Ni or Cu, and their alloys are used in thin films used in internal electrodes of electronic parts that require small size and light weight, and a thin film that can maintain oxidation resistance even in a film forming process accompanied by heating at a high temperature of 600°C or above in the atmosphere is required. In the past, Cr films or Ni films, and Ni-Cr alloy films in which Cr is added to Ni, are known as thin films with high oxidation resistance. These thin films are formed by plating or physical vapor deposition (PVD), that is, vacuum evaporation or sputtering.

[0003] Furthermore, in the manufacture of semiconductor devices, in order to obtain an insulating protective film composed of oxides or nitrides formed by chemical vapor deposition (CVD), corrosive gases are sometimes used as raw gas, and the chamber or device components that decompose and deposit the gas in plasma also require oxidation resistance at high temperatures.

[0004] Furthermore, the chamber of a calcination furnace, an anti-adhesion plate, a tray and other components used when calcining ion active materials that affect the performance of large-capacity batteries indispensable for mobile products in an oxygen atmosphere are also required to have oxidation resistance at high temperatures.

[0005] At present, Ni-based alloys are used in device components used in CVD devices or calcining furnaces in order to have oxidation resistance at high temperatures and necessary strength. For example, Patent Document 1 proposes a Ni-based alloy containing, by mass%, 3.6% to 4.4% Al, 0.1% to 2.5% Si, 0.8% to 4.0% Cr, and 0.1% to 1.5% Mn, or one or more thereof, with the remainder containing Ni and unavoidable impurities.

[0006] In addition, Patent Document 2 proposes a Ni-based alloy, which contains, by mass%, Al: 0.05% to 2.5%, Si: 0.3% to 2.5%, Cr: 0.5% to 3.0%, and Mn: 0.5% to 1.8%, with Si / Cr < 1.1 or less, and the remainder containing Ni and unavoidable impurities, and has excellent heat resistance and corrosion resistance.

[0007] Patent Document 3 proposes a member in which a Ni—Al alloy layer is formed on the surface of a substrate made of pure Ni or a Ni—Cr—Fe alloy by calorizing.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent No. 3814822

[0011] Patent Document 2: Japanese Patent Laid-Open No. 2-163336

[0012] Patent Document 3: Japanese Patent Application Publication No. 2012-219369 Summary of the invention

[0013] Problems to be solved by the invention

[0014] As described above, regarding thin films containing Cr, such as Cr films or Ni-Cr alloy films, which are representative materials with excellent oxidation resistance, there is a trend to stop using thin films containing Cr, considering the possibility that ionized Cr becomes hexavalent Cr during photolithography in electronic components and the environmental impact when electronic components are discarded.

[0015] On the other hand, a thin film containing pure Ni has excellent moisture resistance, but is inferior to a thin film containing Cr in oxidation resistance. An oxide layer is generated on the surface at 400°C, causing discoloration, and the oxide layer diffuses into the functional film of the electronic component, causing degradation of the characteristics.

[0016] Furthermore, pure Ni is a magnetic body, and therefore, when magnetron sputtering, which is a general thin film forming method, is applied, the thickness of the sputtering target must be reduced, which makes it difficult to form a thin film efficiently.

[0017] In recent years, there has been a demand for improved properties of ion active materials in large-capacity batteries, but since Cr contained in the internal components of a CVD device or a calcining furnace used in the production of the ion active materials is included in the active species, there is a concern that the properties may be deteriorated.

[0018] In addition, the aluminizing treatment requires heating the alloy powder or the preparation in a sealed container at about 1000°C, and the treatment takes time. In addition, the film thickness needs to be 10 μm or more, and in order to form a high-precision component, the surface needs to be cut by grinding, etc., which is a problem that it takes a lot of time.

[0019] An object of the present invention is to provide a Ni alloy film having high oxidation resistance at high temperatures even without containing Cr, and a sputtering target for forming the same.

[0020] Technical means of solving problems

[0021] The present inventors have conducted intensive research on a new alloy that can achieve high oxidation resistance at high temperatures. As a result, they have found that high oxidation resistance at high temperatures can be achieved by adding predetermined amounts of Al and V to Ni, thereby arriving at the present invention.

[0022] That is, the present invention is an invention of a Ni alloy film containing 9.0 atomic % to 25.0 atomic % of Al, 1.0 atomic % to 8.0 atomic % of V, and the remainder containing Ni and inevitable impurities.

[0023] The Ni alloy film of the present invention preferably contains 11.0 atomic % to 30.0 atomic % of Al and V in total.

[0024] Furthermore, the Ni alloy film of the present invention preferably contains 10.0 atomic % to 18.0 atomic % of Al.

[0025] Furthermore, the Ni alloy film of the present invention more preferably contains 11.0 to 16.0 atomic % of Al and 2.5 to 3.5 atomic % of V.

[0026] In addition, the present invention is an invention of a sputtering target for forming a Ni alloy film, wherein the sputtering target contains 9.0 atomic % to 25.0 atomic % of Al, 1.0 atomic % to 8.0 atomic % of V, and the remainder contains Ni and inevitable impurities, and has a Curie point below room temperature.

[0027] The sputtering target for forming a Ni alloy film of the present invention preferably contains 11.0 atomic % to 30.0 atomic % of Al and V in total.

[0028] In addition, the sputtering target for forming a Ni alloy film preferably contains 10.0 atomic % to 18.0 atomic % of Al.

[0029] Furthermore, the sputtering target for forming a Ni alloy film of the present invention more preferably contains 11.0 to 16.0 atomic % of Al and 2.5 to 3.5 atomic % of V.

[0030] Effects of the Invention

[0031] The present invention can provide a Ni alloy film that can suppress surface oxidation and internal oxidation of the Ni alloy film itself even if it does not contain Cr and even if it undergoes a high-temperature heating process in the atmosphere at 600° C. or higher, and can exhibit excellent oxidation resistance at high temperatures. Therefore, the present invention can contribute to the miniaturization and lightness of various electronic parts, the high integration, and the large capacity of batteries, and can also help reduce the environmental impact when discarded. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] [ Figure 1 ] Figure 1 This is an example of a schematic cross-sectional view of the Ni alloy film of the present invention. DETAILED DESCRIPTION

[0033] exist Figure 1 An example of a schematic cross-sectional view of the Ni alloy film of the present invention is shown. The Ni alloy film 2 of the present invention is formed, for example, on the surface of the substrate 1. Moreover, the Ni alloy film of the present invention has the following characteristics: the film thickness is thin and even if Cr, which is a necessary additive element in the oxidation-resistant alloy in the past, is not contained, oxidation resistance at high temperature is achieved.

[0034] In addition, "oxidation resistance" can be confirmed by the discoloration of the Ni alloy film accompanied by surface oxidation when heated in an oxygen-containing environment, and can be quantitatively evaluated by, for example, reflectivity. In addition, "internal oxidation" means that oxidation proceeds from the surface of the Ni alloy film to the inside.

[0035] If the oxidation of the Ni alloy film formed on the surface of the internal electrode or device member of the electronic component proceeds to the interface with the internal electrode or device member of the electronic component, the resistance value may increase in the case of the internal electrode, and the strength may decrease in the case of the device member. In addition, the adhesion of the Ni alloy film may decrease and fall off, thereby losing the anti-oxidation function. Therefore, it is necessary that the oxidation of the Ni alloy film does not proceed to the interface with the internal electrode or device member even if the film thickness is thin, that is, internal oxidation is suppressed.

[0036] Here, the confirmation of "internal oxidation" of the Ni alloy film can be confirmed, for example, by forming a Ni alloy film on a transparent glass substrate, heating it in the atmosphere, and observing the discoloration or loss of metallic color of the Ni alloy film at this time from the glass surface side, and can be quantitatively evaluated by reflectivity.

[0037] The Ni alloy film of the present invention contains 9.0 atomic % to 25.0 atomic % of Al, 1.0 atomic % to 8.0 atomic % of V, and the remainder contains Ni and unavoidable impurities.

[0038] Al and V are both elements that are more easily oxidized than Ni. Among the elements constituting the Ni alloy film of the present invention, Al is the most easily oxidized element and is easily diffused in Ni. When heated in the air, Al diffuses into the surface layer of the thin film to form an oxide layer.

[0039] On the other hand, V is an element that is less oxidizable than Al and diffuses more slowly in Ni than Al. When V is contained alone in Ni, it has an effect of improving oxidation resistance compared to Al at temperatures below 300°C, but internal oxidation proceeds with rising temperatures.

[0040] In the Ni alloy film of the present invention, when heated in the atmosphere, Al that diffuses quickly and is easily oxidized forms an oxide layer on the surface, and a V layer that diffuses slowly and is less easily oxidized than Al forms thereunder, thereby suppressing diffusion of oxygen from the surface.

[0041] The Ni alloy film of the present invention has an Al content of 9.0 atomic % or more in order to stably generate an Al oxide layer on its surface and suppress internal oxidation. In addition, in order to ensure adhesion with glass, Si wafers or metal foils, and various metal components as substrates, Al needs to be 9.0 atomic % or more.

[0042] Among them, if the content of Al exceeds 25.0 atomic %, the effect of suppressing internal oxidation is reduced. Therefore, the content of Al in the Ni alloy film of the present invention is set to be less than 25.0 atomic %. In addition, for the same reasons as described above, the content of Al in the Ni alloy film of the present invention is preferably set to be less than 23.0 atomic %.

[0043] In the Ni alloy film of the present invention, the V content is set to 1.0 atomic % or more in order to obtain the effect of suppressing internal oxidation by generating V between the Al oxide layer and the Ni alloy matrix during heating.

[0044] However, if the content of V exceeds 8.0 atomic %, oxidation of V itself may be promoted, thereby reducing oxidation resistance. Therefore, the content of V in the Ni alloy film of the present invention is set to 8.0 atomic % or less.

[0045] The Ni alloy film of the embodiment of the present invention can fully obtain the effect of suppressing internal oxidation by setting the total content of Al and V to 11.0 atomic % or more. On the other hand, by setting the total content of Al and V to 30.0 atomic %, oxidation resistance can be ensured and the formed Ni alloy film can be suppressed from becoming brittle. Therefore, the Ni alloy film of the present invention preferably contains 11.0 atomic % to 30.0 atomic % of Al and V in total. In addition, for the same reasons as described above, the Ni alloy film of the present invention is more preferably Al and V containing 11.0 atomic % to 28.0 atomic % in total.

[0046] The Ni alloy film of the embodiment of the present invention can suppress discoloration caused by surface oxidation of the Ni alloy film itself by setting the Al content to 10.0 atomic % or more or 18.0 atomic % or less. Therefore, the Ni alloy film of the present invention preferably contains 10.0 atomic % to 18.0 atomic % of Al.

[0047] In addition, in the Ni alloy film of the embodiment of the present invention, in order to suppress the surface oxidation of the Ni alloy film itself at high temperatures, Al is more preferably contained in an amount of 11.0 atomic % to 16.0 atomic %, and V is more preferably contained in an amount of 2.5 atomic % to 3.5 atomic %. Furthermore, in order to obtain the oxidation resistance effect at high temperatures, the Al content is preferably greater than the V content, preferably 1.5 times or more of the V content.

[0048] In the Ni alloy film of the present invention, in order to ensure the above-mentioned characteristics, the remainder other than Al and V contains Ni and inevitable impurities. Here, the content of inevitable impurities is preferably small, and may contain oxygen, nitrogen or carbon as gas components, Cr, Fe, Cu and other inevitable impurities as transition metals within the range that does not damage the effect of the present invention. For example, the oxygen and nitrogen of the gas components are respectively less than 1000 mass ppm, the carbon is less than 200 mass ppm, and the Cr, Fe, Cu are respectively less than 200 mass ppm, and the purity of the gas components is preferably 99.9 mass % or more.

[0049] In order to form the Ni alloy film of the present invention, it is preferred to use a sputtering method using a sputtering target. When forming a Ni alloy film, for example, the following methods can be applied: a method of forming a film using a sputtering target having the same composition as the composition of the Ni alloy film, or a method of forming a film by co-sputtering using a sputtering target containing a Ni-Al alloy and a Ni-V alloy. In terms of the simplicity of setting the sputtering conditions or the ease of obtaining a Ni alloy film of the desired composition, it is most preferred to use a sputtering target having the same composition as the composition of the Ni alloy film for sputtering film formation. Therefore, the sputtering target of the present invention contains 9.0 atomic % to 25.0 atomic % of Al, 1.0 atomic % to 8.0 atomic % of V, and the remainder contains Ni and unavoidable impurities.

[0050] Furthermore, for the same reason as described above, the sputtering target according to the embodiment of the present invention preferably contains 11.0 atomic % to 30.0 atomic % of Al and V in total.

[0051] In addition, for the same reason as described above, the sputtering target according to the embodiment of the present invention preferably contains 10.0 atomic % to 18.0 atomic % of Al.

[0052] In addition, for the same reason as described above, the sputtering target according to the embodiment of the present invention more preferably contains 11.0 atomic % to 16.0 atomic % of Al and 2.5 atomic % to 3.5 atomic % of V.

[0053] In the sputtering target for forming a Ni alloy film of the present invention, in order to ensure the above-mentioned characteristics, the remainder other than Al and V contains Ni and inevitable impurities. Here, the content of inevitable impurities is preferably small, and may contain oxygen, nitrogen or carbon as gas components, Cr, Fe, Cu and other inevitable impurities as transition metals within the range that does not damage the effect of the present invention. For example, the oxygen and nitrogen of the gas components are respectively less than 1000 mass ppm, the carbon is less than 200 mass ppm, and the Cr, Fe, and Cu are respectively less than 200 mass ppm, and the purity of the gas components is preferably 99.9 mass % or more.

[0054] In addition, the Curie point of the sputtering target of the present invention is below room temperature. In the magnetron sputtering method, in order to efficiently form a Ni alloy film, the sputtering target is non-magnetic at room temperature, that is, the Curie point is set below room temperature. In addition, the "room temperature" mentioned here refers to the range of 5°C to 35°C specified in Japanese Industrial Standards (JIS) Z 8703.

[0055] Ni, which is a main constituent element of the Ni alloy film of the present invention, is a magnetic body. To lower the Curie point to room temperature or below, it is important to alloy Ni with Al and V, which are non-magnetic elements constituting the composition of the Ni alloy film of the present invention.

[0056] Furthermore, the sputtering target can be manufactured by, for example, machining an ingot produced by melting a raw material adjusted to a predetermined composition or by a powder sintering method. In the powder sintering method, alloy powder can be manufactured by gas atomization as the raw material powder, or a mixed powder obtained by mixing a plurality of alloy powders or pure metal powders in a manner to obtain the final composition of the present invention can be used as the raw material powder.

[0057] Example 1

[0058] In order to obtain a Ni alloy film, a sputtering target is prepared.

[0059] The raw materials were weighed to form a binary composition of non-magnetic Ni-13.0 atomic % Al, Ni-7.0 atomic % V, Ni-10.0 atomic % V, Ni-10.0 atomic % Cr, Ni-10.0 atomic % Si, and a ternary composition of Ni-14.0 atomic % Al-3.5 atomic % V, and then an ingot was made by a melting casting method in a vacuum melting furnace. In addition, a sputtering target of Ni-50.0 atomic % Al was obtained by making an ingot made by sintering an alloy powder of the same composition.

[0060] Each of the ingots was processed into a plate shape by hot plastic working, and after heat treatment to remove strain, a disk-shaped sputtering target having a diameter of 100 mm and a thickness of 5 mm was produced by mechanical working.

[0061] When a SmCo magnet was brought close to each of the sputtering targets obtained above, the magnet was not attracted, and it was confirmed that the target was non-magnetic at room temperature.

[0062] After each sputtering target was welded to a copper backing plate using In, it was installed in a sputtering device (model number: CS-200) manufactured by Ulvac Co., Ltd., and a sputtering test was carried out under the conditions of Ar environment, pressure 0.5 Pa, and power 500 W. The results showed that all the sputtering targets could be sputtered.

[0063] Various Ni alloy films of 500 nm were formed on a glass substrate (Eagle-XG manufactured by Corning) by co-sputtering in which the sputtering targets obtained above were combined and film-formed simultaneously. In addition, the Ni alloy film formed on the polyimide film under the same conditions as above was dissolved in a solution containing hydrofluoric acid, and the composition was analyzed by inductively coupled plasma (ICP) emission spectrometry.

[0064] Each of the Ni alloy films produced as described above was subjected to heat treatment at 600° C. and 700° C. in the atmosphere, and then the reflectance was measured. The reflectance was measured using a spectrophotometric colorimetric system CM-2500d manufactured by KONICA MINOLTA.

[0065] Internal oxidation was evaluated by observing the reflectivity and color tone of the Ni alloy film from the transparent glass surface after heating at 700°C. In the case of a metallic color, internal oxidation was determined to be suppressed, and in the case of discoloration, the film was determined to be oxidized as a whole and internal oxidation was carried out. The measurement results are shown in Table 1.

[0066] [Table 1]

[0067]

[0068] Regarding the Ni alloy films of Samples No. 1 to No. 10 containing specified amounts of Al and V as examples of the present invention, the Ni alloy films were observed from the glass surface side after heating at 700° C., and it was confirmed that the metallic color was maintained, the reflectivity was as high as 50% or more, and internal oxidation was suppressed.

[0069] In addition, sample No. 11 as a comparative example containing Cr also had a metallic color on the glass surface side after heating at 700° C. In addition, in sample No. 12 containing no Cr, sample No. 13 and sample No. 14 having a small Al content, it was confirmed that the Ni alloy film on the glass surface side had no metallic color and changed color, and its reflectivity also decreased significantly, and the entire film was oxidized due to internal oxidation.

[0070] The reflectivity of the Ni alloy film surface during film formation was 54% to 58%. In addition, the reflectivity of the Ni alloy film of sample No. 11 containing Cr as a comparative example was confirmed to be reduced to less than 20% after heating at 600°C and 700°C, indicating that the oxidation resistance of the Ni alloy film surface was low.

[0071] In contrast, samples No. 1 to No. 10 containing Al and V in Ni within the range of the present invention were confirmed to have a high reflectivity of more than 25% even after heating at 700°C, and the oxidation resistance of the Ni alloy film surface was also high. Among them, the Ni alloy films of samples No. 3, No. 4, No. 6, No. 7, and No. 8, which are examples of the present invention, were confirmed to have a high reflectivity of more than 55% even after heating at 700°C, and were excellent in high temperature oxidation resistance.

[0072] Example 2

[0073] Using the targets of Ni-14.0 atomic % Al-3.5 atomic % V and Ni-10.0 atomic % Cr prepared in Example 1, an Ar atmosphere, a pressure of 0.5 Pa, a power of 500 W, and adjusting the film formation time, a Ni alloy film with a film thickness of 100 nm to 500 nm was formed on a glass substrate in the same manner as in Example 1. In addition, a pure Ni target was prepared and formed on a glass substrate to obtain a pure Ni film as a comparative example.

[0074] Each of the Ni alloy films and pure Ni films obtained above was subjected to a heat treatment at 700° C. in the air, and then the reflectance was measured in the same manner as in Example 1. Table 2 shows the results.

[0075] [Table 2]

[0076]

[0077] As shown in Table 2, the pure Ni film as a comparative example peeled off due to oxidation of the entire film, so the reflectivity could not be measured. In addition, the Ni-10.0 atomic % Cr containing Cr as a comparative example also confirmed that the reflection on the glass side was as high as 50% or more when the film thickness was 150 nm or more, and the internal oxidation was suppressed, but the reflectivity on the Ni alloy film side decreased to less than 30% in the film thickness range of 100 nm to 500 nm after heating at 700°C, and the oxidation resistance was poor.

[0078] In contrast, Ni-14.0 atomic % Al-3.5 atomic % V as an example of the present invention was confirmed to have a reflectivity on the glass surface side exceeding 50% when the film thickness is 150 nm or more, similar to Ni-10.0 atomic % Cr, which inhibits internal oxidation, and a reflectivity on the Ni alloy film surface side exceeding 30% when the film thickness is 150 nm or more, and the reflectivity increases with increasing film thickness, which shows excellent oxidation resistance compared to Ni-10.0 atomic % Cr.

[0079] As described above, the Ni alloy of the present invention has been confirmed to suppress internal oxidation similarly to Ni-10 atomic % Cr, even though it does not contain Cr, and also has a high reflectivity on the Ni alloy film surface side, thus being a Ni alloy film with high oxidation resistance.

[0080] Description of Figure Numbers

[0081] 1: Base material

[0082] 2: Ni alloy film

Claims

1. A Ni alloy film comprising 9.0 atomic % to 25.0 atomic % of Al, 1.0 atomic % to 8.0 atomic % of V, and the remainder comprising Ni and unavoidable impurities. 2 . The Ni alloy film according to claim 1 , comprising 11.0 atomic % to 30.0 atomic % of Al and V in total. 3 . The Ni alloy film according to claim 1 , comprising 10.0 atomic % to 18.0 atomic % of Al. 4 . The Ni alloy film according to claim 1 , comprising 11.0 to 16.0 atomic % of Al and 2.5 to 3.5 atomic % of V.

5. A sputtering target for forming a Ni alloy film, comprising 9.0 atomic % to 25.0 atomic % of Al, 1.0 atomic % to 8.0 atomic % of V, the remainder of which comprises Ni and unavoidable impurities, and having a Curie point below room temperature. 6 . The sputtering target for forming a Ni alloy film according to claim 5 , comprising 11.0 atomic % to 30.0 atomic % of Al and V in total. 7 . The sputtering target for forming a Ni alloy film according to claim 5 , comprising 10.0 atomic % to 18.0 atomic % of Al. 8 . The sputtering target for forming a Ni alloy film according to claim 5 , comprising 11.0 to 16.0 atomic % of Al and 2.5 to 3.5 atomic % of V.

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