JP2015131996A - Sputtering target material and wiring laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of reducing formation cost and improving productivity, when forming a coating layer on either main surface of a main conductive layer.SOLUTION: A coating layer is formed by using a sputtering target material formed of a copper alloy in which the content of Ni is 30 wt.% or more and 45 wt.% or less, the content of Zn is 10 wt.% or more and 30 wt.% or less, the total content of Ni and Zn is 55 wt.% or more and 65 wt.% or less, and the residue comprises copper and inevitable impurities.

Description

  The present invention relates to a sputtering target material and a wiring laminate.

As a pixel driving element of a flat panel display (hereinafter referred to as FPD) such as a liquid crystal display or an organic EL display, for example, a thin film transistor (hereinafter referred to as TFT) is used. In recent years, the development of next-generation FPDs such as higher-brightness organic EL displays and higher-definition liquid crystal displays has been promoted. The TFT used in these next-generation FPDs is formed, for example, by a wiring laminate including a substrate provided with a semiconductor layer and a main conductive layer provided on the substrate (semiconductor layer) and on which wiring is formed. ing. As a semiconductor layer of a TFT, an oxide semiconductor made of oxides of indium (In), gallium (Ga), and zinc (Zn) is generally provided. On the main conductive layer, an oxide such as silicon oxide (SiO ₂ film) is provided as an insulating film. With the recent increase in FPD screen and resolution, TFTs are required to have low wiring resistance. Thus, the use of copper (Cu) as a material for realizing a reduction in wiring resistance has been studied. That is, the adoption of Cu wiring is progressing as a low resistance wiring. Specifically, it has been proposed to form the main conductive layer with Cu.

However, Cu wiring can realize low resistance, but is easily oxidized in an oxidizing atmosphere such as in the air. For example, when an SiO ₂ film as an insulating film is formed on a Cu wiring, the underlying Cu wiring is oxidized by coming into contact with an oxidizing gas used in the formation (deposition) of the SiO ₂ film. Further, the Cu wiring may be oxidized by oxygen contained in the oxide semiconductor itself as the semiconductor layer. When the Cu wiring is oxidized, the resistance value of the Cu wiring may increase.

  Therefore, in order to suppress the oxidation of the Cu wiring, a technique has been proposed in which a coating layer formed of a molybdenum (Mo) alloy having high oxidation resistance is provided between the Cu wiring and the insulating film (for example, a patent) Reference 1). In addition, a technique has been proposed in which a coating layer made of a NiCu alloy containing nickel (Ni) at a high concentration is provided between a Cu wiring and an insulating film (see, for example, Patent Document 2). The coating layer is formed by sputtering using a target material.

JP 2013-60656 A JP 2012-193444 A

  However, Mo is very expensive. Further, when the wiring laminate is etched to form a Cu wiring in the main conductive layer, it is necessary to use an expensive etching solution in order to match the etching rates of Mo and Cu. In other words, the technique described in Patent Document 1 may increase the manufacturing cost of TFTs and FPDs.

  Moreover, since Ni has magnetism, when a target material containing Ni at a high concentration is used, the sputtering rate is lowered. Further, the NiCu alloy layer has a lower etching rate than the main conductive layer formed of Cu. That is, the technique described in Patent Document 2 may cause a reduction in TFT and FPD productivity.

  An object of the present invention is to solve the above-mentioned problems and to provide a technique for reducing the formation cost and improving the productivity when a coating layer is formed on a main conductive layer.

In order to solve the above problems, the present invention is configured as follows.
According to the first aspect of the present invention, the nickel content is 30 wt% or more and 45 wt% or less, the zinc content is 10 wt% or more and 30 wt% or less, and the total content of the nickel and the zinc is 55 wt%. % To 65 wt%, and a sputtering target material formed of a copper alloy, the balance of which is made of copper and inevitable impurities, is provided.

  According to a second aspect of the present invention, there is provided the sputtering target material according to the first aspect, wherein the copper is oxygen-free copper.

  According to a third aspect of the present invention, there is provided a substrate and a main conductive layer provided on the substrate and formed of copper, and the main conductive layer has the first or second aspect. Provided is a wiring laminate in which a coating layer formed using a sputtering target material is provided.

  According to the present invention, when the coating layer is formed on the main conductive layer, the formation cost can be reduced and the productivity can be improved.

It is a schematic sectional drawing of the wiring laminated body formed using the sputtering target material concerning one Embodiment of this invention. It is a schematic sectional drawing of the wiring laminated body formed using the sputtering target material concerning other embodiment of this invention.

<One Embodiment of the Present Invention>
First, the structure of the wiring laminated body concerning one Embodiment of this invention is demonstrated, referring FIG.

(1) Configuration of Wiring Stack As shown in FIG. 1, a wiring stack 10 according to this embodiment is provided on a substrate 1 including a semiconductor layer and on the substrate 1 (on the semiconductor layer included in the substrate 1). A conductive layer 2 and an insulating film 3 provided on the main conductive layer 2 are provided. As the substrate 1, for example, a glass substrate, a silicon (Si) substrate, or the like is used. The main conductive layer 2 is made of copper (Cu) (for example, pure copper) and functions as a wiring film (main wiring film) on which wiring is formed. The main conductive layer 2 also functions as an electrode. The insulating film 3 is formed of, for example, a silicon oxide (SiO ₂ ) film. The semiconductor layer is formed of an oxide semiconductor made of oxide (IGZO) of indium (In), gallium (Ga), and zinc (Zn), for example.

  Between the substrate 1 and the main conductive layer 2, a first covering layer (base layer) 4A is provided. Between the main conductive layer 2 and the insulating film 3, a second coating layer (cap layer) 4B is provided. The first and second coating layers 4A and 4B each function as a protective film (electrode protective film) that suppresses oxidation of the main conductive layer 2. That is, the first and second coating layers 4A and 4B each function as a barrier layer (block layer) that suppresses the main conductive layer 2 from coming into contact with oxygen. The first and second coating layers 4A and 4B are each formed of a copper alloy containing a predetermined amount of nickel (Ni) and a predetermined amount of zinc (Zn). Specifically, the first and second coating layers 4A and 4B are formed by sputtering (for example, magnetron sputtering) using a sputtering target material, which will be described later, containing a predetermined amount of Ni and a predetermined amount of Zn, respectively.

  Such a wiring laminated body 10 is used as a wiring material of a semiconductor device such as a thin film transistor (TFT).

(2) Configuration of Sputtering Target Material Hereinafter, the sputtering target material used for forming the first coating layer 4A and the second coating layer 4B will be described. That is, a sputtering target material used for forming a protective film (electrode protective film) that suppresses oxidation of the main conductive layer 2 will be described.

  A sputtering target material according to the present embodiment (hereinafter also simply referred to as a target material) is formed of a copper alloy containing a predetermined amount of Ni and a predetermined amount of Zn, with the remainder being formed of Cu and inevitable impurities. ing. That is, the target material is formed of a copper alloy containing Cu as a base material and containing a predetermined amount of Ni and a predetermined amount of Zn in the base material. Thereby, the oxidation of the first and second coating layers 4A and 4B can be suppressed. As a result, oxidation of the main conductive layer 2 can be suppressed.

  As the base material Cu, for example, oxygen free copper (OFC) having a purity of 99.9% or more may be used.

  The target material is formed of a copper alloy having a Ni content of 30 wt% to 45 wt%, preferably 35 wt% to 40 wt%.

  By setting the Ni content to 30 wt% or more, the oxidation resistance of the first and second coating layers 4A and 4B can be improved. By setting the Ni content to 35 wt% or more, the oxidation resistance of the first and second coating layers 4A and 4B can be further improved. That is, the effect of suppressing the oxidation of the first and second coating layers 4A and 4B due to containing Ni depends on the Ni content. Therefore, the effect of suppressing the oxidation of the first and second coating layers 4A and 4B increases as the Ni content increases. Note that if the Ni content is less than 30 wt%, the oxidation resistance of the first and second coating layers 4A and 4B decreases.

  By making the Ni content 45 wt% or less, it is possible to suppress a decrease in the magnetic permeability of the target material. That is, the magnetic permeability of the target material can be increased by reducing the content of Ni having magnetism. Thereby, the sputtering rate of the target material can be improved. Therefore, the productivity of the wiring laminate 10 can be improved. By setting the Ni content to 40 wt% or less, the magnetic permeability of the target material can be further increased. When the Ni content exceeds 45 wt%, the Ni content increases, the magnetic permeability of the target material decreases significantly, and the sputtering rate decreases significantly.

  Moreover, the fall of the etching rate of 1st and 2nd coating layer 4A, 4B can be suppressed because content of Ni shall be 45 wt% or less. That is, the difference in etching rate between the first and second coating layers 4A and 4B and the main conductive layer 2 formed of Cu can be reduced. Thereby, for example, when a wiring is formed in the main conductive layer 2 by etching using an etching solution, a step is generated at the interface between the main conductive layer 2 and the first or second coating layer 4A, 4B. Can be suppressed. As a result, a wiring having a desired shape can be formed on the main conductive layer 2 with high accuracy. By setting the Ni content to 40 wt% or less, a decrease in the etching rate of the first and second coating layers 4A and 4B can be further suppressed. When the Ni content exceeds 45 wt%, the etching rate of the first and second coating layers 4A and 4B is significantly reduced. That is, the difference in etching rate between the first and second coating layers 4A and 4B and the main conductive layer 2 formed of Cu is increased.

  The target material is formed of a copper alloy having a Zn content of 10 wt% to 30 wt%, preferably 20 wt% to 25 wt%.

  By setting the Zn content to 10 wt% or more, the oxidation resistance of the first and second coating layers 4A and 4B can be improved. By setting the Zn content to 20 wt% or more, the oxidation resistance of the first and second coating layers 4A and 4B can be further improved. That is, the effect of suppressing the oxidation of the first and second coating layers 4A and 4B due to containing Zn depends on the Zn content. Therefore, as the Zn content increases, the effect of suppressing the oxidation of the first and second coating layers 4A and 4B increases. If the Zn content is less than 10 wt%, the oxidation resistance of the first and second coating layers 4A and 4B cannot be improved unless the Ni content is increased. As a result, the content of magnetic Ni cannot be reduced, and the magnetic permeability of the target material becomes high.

By making the Zn content 30 wt% or less, workability can be improved. For example, it is possible to suppress the occurrence of cracks in the target material during rolling such as hot rolling or cold rolling when forming the target material. By making the Zn content 25 wt% or less, the occurrence of cracks during rolling can be further suppressed. When the Zn content exceeds 30 wt%, the amount of intermetallic compounds (for example, CuZn and Cu ₃ Zn ₈ ) generated in the copper alloy increases. Such an intermetallic compound is oxidized and embrittled when heated during rolling, for example. Therefore, the ductility of the target material is reduced, and cracking occurs during rolling.

  The target material has Ni and Zn contents within the above-mentioned predetermined ranges, respectively, and the total of the Ni content and the Zn content (total content of Ni and Zn) is 55 wt% or more and 65 wt% or less. Preferably, it is made of a copper alloy that is 57 wt% or more and 62 wt% or less.

  When the total content of Ni and Zn is 55 wt% or more, the oxidation resistance of the first and second coating layers 4A and 4B can be improved. By setting the total content of Ni and Zn to 57 wt% or more, the oxidation resistance of the first and second coating layers 4A and 4B can be further improved. That is, the effect of suppressing oxidation of the first and second coating layers 4A and 4B increases as the total content of Ni and Zn increases. When the total content of Ni and Zn is less than 55 wt%, the oxidation resistance of the first and second coating layers 4A and 4B is lowered.

  By setting the total content of Ni and Zn to 65 wt% or less, a decrease in the etching rate of the first and second coating layers 4A and 4B can be suppressed. By setting the total content of Ni and Zn to 62 wt% or more, it is possible to further suppress a decrease in the etching rate of the first and second coating layers 4A and 4B. When the total content of Ni and Zn exceeds 65 wt%, the etching rate of the first and second coating layers 4A and 4B is significantly reduced. That is, the difference in etching rate between the first and second coating layers 4A and 4B and the main conductive layer 2 formed of Cu is increased.

(3) Manufacturing method of sputtering target material Next, the manufacturing method of the sputtering target material concerning this embodiment is illustrated, for example, illustrating a melt casting method.

(Casting process)
First, Cu as a base material is melted using, for example, a high-frequency melting furnace or the like to form a molten copper. Subsequently, a predetermined amount of Ni and a predetermined amount of Zn are added and mixed in the molten copper to form a molten copper alloy. At this time, the Ni content is 30 wt% or more and 45 wt% or less, the Zn content is 10 wt% or more and 30 wt% or less, the total content of Ni and Zn is 55 wt% or more and 65 wt% or less, and the balance is Cu and inevitable The addition amount of each component is adjusted so that it may consist of impurities. Then, the molten copper alloy is poured into a mold (and poured out) and cooled to cast a copper alloy ingot containing a predetermined amount of Ni and Zn.

(Rolling process)
After the casting process is completed, the ingot is heated at a predetermined temperature (for example, 700 ° C. or more) for a predetermined time (for example, 2 hours), and hot-rolled at a predetermined processing degree (for example, a total processing degree of 90%). A hot rolled material having a thickness (for example, 10 mm) is formed. Thereafter, the hot-rolled material is subjected to one or more cold rollings at a predetermined degree of processing and one or more annealing treatments as necessary, and cold rolling with a predetermined thickness (for example, 8 mm) is performed. A material (that is, a target material) is formed.

(Cutting process)
After the rolling process is completed, for example, NC milling is used to perform cutting so that the cold rolled material (target material) has a predetermined thickness. Thereby, the sputtering target material which concerns on this embodiment is manufactured.

(4) Effects According to the Present Embodiment According to the present embodiment, one or more effects described below are exhibited.

(A) According to the present embodiment, the target material is formed of a copper alloy containing 30 wt% or more and 45 wt% or less of Ni, 10 wt% or more and 30 wt% or less of Zn, and the balance of Cu and inevitable impurities. Further, the first and second coating layers 4A and 4B of the wiring laminate 10 shown in FIG. 1 are formed using the target material according to the present embodiment. Thereby, the oxidation of the main conductive layer 2 can be suppressed. Therefore, an increase in resistance value due to oxidation of the main conductive layer 2 can be suppressed. For example, an increase in resistance value of wiring resistance due to oxidation of Cu wiring can be suppressed.

  Specifically, the first coating layer 4A is formed using the target material (a). Thereby, the semiconductor layer with which the board | substrate 1 is provided, and the main conductive layer 2 do not contact. Therefore, when the semiconductor layer is formed of, for example, IGZO, oxidation of the main conductive layer 2 due to oxygen included in the semiconductor layer can be suppressed.

Moreover, the 2nd coating layer 4B is formed using the target material of said (a). Thereby, when forming the SiO ₂ film as the insulating film on the main conductive layer 2, it is possible to suppress the oxidizing gas used for the formation (film formation) of the SiO ₂ film from coming into contact with the main conductive layer 2. Therefore, oxidation of the main conductive layer 2 can be suppressed. Thus, this embodiment is effective when the insulating film 3 is formed of an oxide film such as a SiO ₂ film. Specifically, it is effective when an oxidizing gas containing oxygen is used when forming the insulating film 3. That is, it is particularly effective when used as a wiring laminate for a high-performance FPD in which a non-oxygen-containing film such as a SiN film cannot be used as the insulating film 3.

(B) According to the present embodiment, the first and second coating layers 4A and 4B are formed using the target material (a). Thereby, the oxidation of 1st and 2nd coating layer 4A, 4B itself can also be suppressed. That is, the oxidation resistance of the first and second coating layers 4A and 4B can be improved. Therefore, the oxidation of the main conductive layer 2 in contact with the first and second coating layers 4A and 4B can be further suppressed.

(C) According to this embodiment, the target material contains a predetermined amount of Ni and a predetermined amount of Zn. That is, it contains a predetermined amount of Zn. Thereby, even if it reduces content of Ni, the oxidation resistance of 1st, 2nd coating layer 4A, 4B formed using a target material can be improved. Moreover, since content of Ni which has magnetism can be reduced, the fall of the magnetic permeability of a target material can be suppressed. It should be noted that with the addition of either Ni or Zn, it is difficult to improve the oxidation resistance of the layer formed using the target material unless Ni or Zn is added at a considerably high concentration.

(D) According to the present embodiment, the target material is formed of a copper alloy having a Ni content of 30 wt% or more and 45 wt% or less. Thereby, the oxidation resistance of the 1st and 2nd coating layers 4A and 4B formed using a target material can be improved. Moreover, the fall of the magnetic permeability of a target material can be suppressed. Moreover, the fall of the etching rate of 1st and 2nd coating layer 4A, 4B can be suppressed.

(E) According to this embodiment, the target material is formed of a copper alloy having a Zn content of 10 wt% or more and 30 wt% or less. Thereby, workability (for example, rolling workability) can be improved, improving the oxidation resistance of 1st and 2nd coating layer 4A, 4B formed using a target material. Moreover, the productivity of the target material can be improved by improving the workability. Thereby, the manufacturing cost of a target material can be reduced.

(F) According to the present embodiment, the target material is a copper alloy in which the contents of Ni and Zn are within the above-mentioned predetermined ranges, respectively, and the total content of Ni and Zn is 55 wt% or more and 65 wt% or less It is formed with. Thereby, the fall of the etching rate of 1st and 2nd coating layer 4A, 4B can be suppressed, improving the oxidation resistance of 1st and 2nd coating layer 4A, 4B formed using a target material. .

  (G) This embodiment is particularly effective when a wiring is formed in the main conductive layer 2 by performing wet etching using an etching solution. That is, in this embodiment, since the etching rates of the first and second coating layers 4A and 4B and the main conductive layer 2 are close, when performing wet etching, the Cu forming the main conductive layer 2 is It can suppress that it elutes into an etching liquid ahead of the copper alloy which forms 2nd coating layer 4A, 4B. That is, it can suppress that the side surface of the main conductive layer 2 (for example, the side part of the main conductive layer 2 where it has already been etched) is etched. For example, it is possible to suppress the formation of an overhang. That is, the side surface of the first coating layer 4A can be prevented from protruding outward from the lower surface of the main conductive layer 2 (that is, the surface of the main conductive layer 2 in contact with the first coating layer 4A). For example, the side surface of the first coating layer 4A (side surface of the second coating layer 4B) can be prevented from protruding like a ridge from the lower surface (upper surface) of the main conductive layer 2. As a result, the reliability of the wiring formed in the main conductive layer 2 can be further improved.

(H) According to the present embodiment, even when the concentration of inevitable impurities in the copper alloy forming the target material is high, the first and second coating layers 4A and 4B having high oxidation resistance are formed. it can. For example, even if the concentration of inevitable impurities is higher than the concentration of inevitable impurities of oxygen-free copper specified in JIS H3100, the first and second coating layers 4A and 4B having high oxidation resistance are formed. Can be formed. Specifically, the concentration of inevitable impurities in the copper alloy may be less than 1 wt%.

(I) According to the present embodiment, the first and second coating layers 4A and 4B having high oxidation resistance can be formed at low cost. For example, the first and second coating layers 4A and 4B can be formed at a lower cost than the case where the first and second coating layers 4A and 4B are formed of a molybdenum (Mo) alloy.

(J) According to the present embodiment, oxygen-free copper is used as the base material of the copper alloy that forms the target material. For example, oxygen-free copper having a purity of 99.9% or more is used. By using such oxygen-free copper, the oxygen concentration in the first and second coating layers 4A and 4B can be further reduced. Therefore, the oxidation resistance of the first and second coating layers 4A and 4B can be further improved, and the effect (b) can be further obtained. Further, even when oxygen-free copper having a purity lower than that of a conventional target material is used as a base material, the oxidation resistance of a layer (film) formed using this target material can be improved. it can. Accordingly, the effect (h) can be further obtained.

(Other embodiments of the present invention)
As mentioned above, although one Embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the summary, it can change suitably.

  In the above-described embodiment, the first coating layer 4A and the second coating layer 4B are provided as the coating layer. However, the present invention is not limited to this. For example, either the first coating layer 4A or the second coating layer 4B may be provided. That is, it is sufficient that a coating layer is provided on the main conductive layer 2.

  In the above-described embodiment, the wiring laminate 10 including the substrate 1, the first covering layer 4A, the main conductive layer 2, the second covering layer 4B, and the insulating film 3 has been described. It is not limited. For example, a wiring laminate 10A as shown in FIG. 2 may be used. As the substrate 1, for example, a polyethylene terephthalate (PET) film substrate or the like is used. Each of the first coating layer 4A and the second coating layer 4B is formed using the above-described target material. For example, an ITO layer is formed as the transparent conductive layer 5. Also in such a wiring laminate 10A, it is only necessary that the coating layer 4 (the first coating layer 4A and the second coating layer 4B) is provided on any main surface of the main conductive layer 2. Such a wiring laminate 10A can be used as a wiring material such as a touch panel sensor. Even with such a wiring laminate 10A, the above-described effects can be obtained.

  The above-described embodiment is particularly effective when the semiconductor layer included in the substrate 1 is formed of an oxide semiconductor. However, the semiconductor layer may be formed of amorphous silicon or the like.

  In the above-described embodiment, the method for producing the sputtering target material by the melt casting method has been described. However, the present invention is not limited to this. For example, a powder sintering method using Cu, Ni, Zn powder, or a cold spray method in which Cu, Ni, Zn powder is deposited by spraying with an inert gas at high speed may be used.

  Next, examples of the present invention will be described, but the present invention is not limited thereto.

  Samples of Examples 1 to 9 and Comparative Examples 1 to 8 were prepared, and the oxidation resistance, etching rate, sputtering rate, and workability of the alloy film (or pure copper film) formed by sputtering using each sample. Evaluation was performed.

<Preparation of sample>
Example 1
In Example 1, first, oxygen-free copper having a purity of 99.9% or higher was used, and the oxygen-free copper was heated to 1100 ° C. or higher and 1300 ° C. or lower in a high-frequency melting furnace to prepare a molten copper. And while maintaining the heating of the molten copper in the high-frequency melting furnace, the Ni block (Ni lump) having a purity of 99.9% and the Zn block (Zn lump) having a purity of 99.9%, respectively It was added (injected) into the molten copper at a predetermined ratio, and the Ni block and the Zn block were dissolved and mixed to prepare a molten copper alloy. Thereafter, the molten copper alloy is poured into a mold and cooled, and a copper alloy (Cu-30Ni-25Zn) having a Ni content of 30 wt%, a Zn content of 25 wt%, and a total content of Ni and Zn of 55 wt% is used. ) Ingot. After heating the obtained ingot at 800 ° C. for 2 hours, hot rolling with a total workability of 90% was performed to produce a hot rolled material having a thickness of 10 mm. Subsequently, cold rolling with a predetermined degree of processing was performed to produce a cold rolled material (target material) having a thickness of 8 mm. Then, the cold-rolled material was cut by NC milling. Thus, a target material having a thickness of 5 mm and a diameter of 100 mm (5 mm × φ100 mm) was produced. This was used as the sample of Example 1.

(Examples 2-9 and Comparative Examples 1-8)
In Examples 2 to 9 and Comparative Examples 1 to 8, the ratio of the Ni block and Zn block added to the molten copper is changed, and the composition of the copper alloy (ingot) forming the target material is shown in Table 1 below. As shown. Other than that, a target material was produced in the same manner as in Example 1. These were used as samples of Examples 2 to 9 and Comparative Examples 1 to 8, respectively.

<Sputtering method>
In order to evaluate each sample of Examples 1 to 9 and Comparative Examples 1 to 8, that is, to evaluate a film formed by sputtering using each sample, sputtering was performed using each sample, and on a 50 mm × 50 mm glass substrate A predetermined film was formed. As a sputtering apparatus, SH-350 manufactured by ULVAC, Inc. was used. When using each sample of Examples 1-9 and Comparative Examples 1-8 as a target material, each sample and a pure copper backing plate were joined to each other via melted indium (In) and attached to the sputtering apparatus. . That is, each sample was attached to the sputtering apparatus while being joined to the backing plate. The sputtering conditions were as follows. That is, the output was 1 kW (DC), argon (Ar) gas was used as the sputtering gas, and the gas pressure (pressure in the chamber where sputtering was performed) was 0.5 Pa.

<Oxidation resistance evaluation method>
A sample in which a pure copper film having a thickness of 1000 nm and an alloy film having a thickness of 50 nm were formed on a 50 mm × 50 mm glass substrate in this order from the glass substrate side was produced. That is, by using the above-described sputtering method, each sample of Examples 1 to 9 and Comparative Examples 1 to 7 was used as a target material, and an alloy film having a thickness of 50 nm was formed to prepare each sample. The pure copper film was formed by the same method as the sputtering method described above except that a target material made of pure copper (for example, a target material which is a sample of Comparative Example 8) was used. In addition, the sample formed using the sample of the comparative example 8 is a sample which formed only the pure copper film | membrane whose thickness is 1000 nm on a 50 mm x 50 mm glass substrate.

Subsequently, for each sample formed using each sample of Examples 1 to 9 and Comparative Examples 1 to 8 (hereinafter, also referred to as each sample), the electrical resistance was measured by van der Pauw method. The rate (%) was measured. That is, the electrical resistivity was measured by placing needles as electrodes near the four corners of a 3 mm square area. The measured value of the electrical resistivity of each sample at this time is defined as the electrical resistivity before heating. Moreover, each obtained sample was heated at 400 degreeC with the hotplate in air | atmosphere. Thereafter, the electrical resistivity of each sample was measured by the van der Pau method described above. The measured value of the electrical resistivity of each sample (that is, each sample after heating) at this time is defined as the electrical resistivity after heating. And the increase rate (%) of the electrical resistivity was calculated by the following (Formula 1).
(Formula 1)
Rate of increase in electrical resistivity (%) = ((electric resistance before heating−electric resistance after heating) / electric resistance before heating) × 100

  Table 1 below shows the electrical resistivity (%) before heating, the electrical resistivity (%) after heating, and the rate of increase (%) in electrical resistivity of each sample. The smaller the rate of increase in electrical resistivity, the higher the oxidation resistance. It was confirmed that the penetration of oxygen into the pure copper film was serious when the rate of increase in electrical resistivity was 7% or more. That is, it was confirmed that the oxidation of the pure copper film was advanced. Therefore, a sample having an electrical resistivity increase rate of less than 7% was determined to be acceptable (◯).

<Evaluation method of etching rate>
An alloy film having a thickness of 300 nm (pure copper film having a thickness of 300 nm) was formed on a 50 mm × 50 mm glass substrate to prepare a sample. That is, with the above-described sputtering method, each sample of Examples 1 to 9 and Comparative Examples 1 to 7 was used as a target material, an alloy film having a thickness of 300 nm was formed on a glass substrate, and each sample was formed. Produced. In addition, a sample was prepared by forming a pure copper film having a thickness of 300 nm on a glass substrate using the sample of Comparative Example 8 as a target material by the sputtering method described above.

Subsequently, the etching rate ratio was calculated for each sample (hereinafter, also referred to as each sample) formed using the samples of Examples 1 to 9 and Comparative Examples 1 to 8. Specifically, each sample was first immersed in an aqueous solution of 200 g / L ammonium persulfate at 40 ° C. as an etching solution. And the time (etching time) required until the alloy film (pure copper film) disappeared completely from the glass substrate was measured. Then, the etching rate (nm / s) of each sample was calculated by dividing the film thickness by the etching time of each sample. Subsequently, the etching rate ratio of each sample was calculated by the following (formula 2). In addition, the etching rate of the sample of the comparative example 8 was used as an etching rate.
(Formula 2)
Etching rate ratio = etching rate of each sample / etching rate of pure copper film

  The etching rate and etching rate ratio of each sample are shown in Table 1 below. The closer the value of the etching rate ratio is to 1, that is, the smaller the difference between the etching rate of each sample (alloy film) and the etching rate of the pure copper film, the better the etching property. For example, in the wiring laminate 10 shown in FIG. 1, the wiring is formed in the main conductive layer 2 as the difference between the etching rate of the main conductive layer 2 and the etching rates of the first and second coating layers 4A and 4B becomes smaller. At this time, a step is hardly generated at the interface between the main conductive layer 2 and the covering layer 4. As a result, a wiring having a desired wiring shape can be formed in the main conductive layer 2 with high accuracy. When the etching rate ratio was 0.5 or more, it was confirmed that good etching properties were exhibited. For example, it was confirmed that a wiring having a desired wiring shape can be formed with high accuracy in the main conductive layer 2. Therefore, a sample having an etching rate ratio of 0.5 or more was evaluated as acceptable (◯).

<Evaluation method of sputtering rate>
First, a stainless steel mask having a 3 mm × 3 mm opening (window) formed thereon was placed on a 50 mm × 50 mm glass substrate. Then, using each sample of Examples 1-9 and Comparative Examples 1-8 as a target material, it sputters for 1 minute with the above-mentioned sputtering method, forms an alloy film (pure copper film) on a glass substrate, and each A sample was made.

Subsequently, the sputter rate ratio with respect to the pure copper film was calculated for each sample (hereinafter, also referred to as each sample) formed using the samples of Examples 1 to 9 and Comparative Examples 1 to 8. Specifically, first, the mask was removed from each sample. And the film thickness of the alloy film (pure copper film) formed on the glass substrate was measured using the laser microscope VK-8700 by Keyence Corporation. Then, the sputtering rate of each sample was calculated by dividing the film thickness of each sample by the sputtering time (1 minute). Subsequently, the sputtering rate ratio of each sample was calculated by the following (formula 3). Note that the sputtering rate of the sample of Comparative Example 8 was used as the sputtering rate of the pure copper film.
(Formula 3)
Sputter rate ratio = sputter rate of each sample / sputter rate of pure copper film

  The sputter rate and sputter rate ratio of each sample are shown in Table 1 below. As the value of the sputtering rate ratio approaches 1, that is, as the etching rate of each sample (alloy film) approaches the sputtering rate of the pure copper film, the productivity is improved. For example, the productivity of the wiring laminate 10 shown in FIG. 1 is improved. When the etching rate ratio was less than 0.7, it was confirmed that the productivity was significantly lowered. That is, it was confirmed that the film thickness that can be formed per minute (per unit time) is reduced. Therefore, a sample having a sputter rate ratio of 0.7 or more was determined to be acceptable (◯).

<Processing evaluation method>
In addition, the processability of the target material that is each sample was evaluated. That is, it was evaluated whether or not cracking occurred when producing the target material. In the process of producing the target material, when the final cold rolling was performed, the edge portion of the cold rolled material was not cracked, and the cracked material was marked as “Yes”. Evaluation was performed. At the time of the final cold rolling, the one in which no crack occurred in the edge portion of the cold rolled material was regarded as acceptable. The evaluation results of the workability of each sample are shown in Table 1 below.

<Comprehensive evaluation>
Samples that gave good results in any of the evaluations of oxidation resistance, etching rate, sputter rate, and workability were marked with “◯”, and samples that were evaluated as rejected by any one were marked with “x”. It was.

<Evaluation results>
Table 1 shows the results of evaluating the oxidation resistance, etching rate, sputtering rate, and workability of the samples of Examples 1 to 9 and Comparative Examples 1 to 8.

  From Table 1, the alloy films formed using the samples according to Examples 1 to 9 and the samples of Examples 1 to 9 are good in any evaluation of oxidation resistance, etching rate, sputtering rate, and workability. It was confirmed that a satisfactory result was obtained. That is, it was confirmed that all the alloy films formed using the samples of Examples 1 to 9 had high oxidation resistance with an electrical resistivity increase rate of less than 7%. Moreover, it was confirmed that all the alloy films formed using the samples of Examples 1 to 9 had an etching rate ratio of 0.5 or more and good etching properties. Moreover, it was confirmed that all the target materials which are each sample of Examples 1-9 have a sputter rate ratio of 0.7 or more and have a good sputter rate. In addition, it was confirmed that each sample of Examples 1 to 9 had good workability without cracking during the final cold rolling when each sample was produced.

  It was confirmed that the alloy films (pure copper films) formed using the samples of Comparative Examples 1, 3, 5 and 8 had an electrical resistivity increase rate of 7% or more and did not have the desired oxidation resistance. did. That is, an alloy having high oxidation resistance when the Ni content of the target material is less than 30 wt%, the Zn content is less than 10 wt%, or the total content of Ni and Zn is less than 55 wt%. It was confirmed that a film (pure copper film) could not be formed.

  It was confirmed that the alloy films formed using the samples of Comparative Examples 2, 6, and 7 all had an etching rate ratio of less than 0.5. That is, it was confirmed that when the Ni content of the target material exceeds 45 wt%, or the total content of Ni and Zn exceeds 65 wt%, the etching rate of the alloy film decreases. That is, it was confirmed that the difference between the etching rate of the pure copper film and the etching rate of the alloy film becomes large.

  It was confirmed that all of the target materials as the samples of Comparative Examples 2 and 7 had a sputtering rate ratio of less than 0.7. That is, it was confirmed that when the Ni content of the target material exceeds 45 wt%, the sputtering rate of the target material decreases.

  It was confirmed that the target material which is the sample of Comparative Example 4 did not have good workability. That is, when the Zn content of the target material exceeds 30 wt%, the ductility of the target material is lowered. For this reason, it was confirmed that cracks may occur in the target material during production of the target material, particularly during rolling.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Main conductive layer 4A 1st coating layer 4B 2nd coating layer 5 Transparent conductive layer 10 Wiring laminated body

Claims (3)

The nickel content is 30 wt% or more and 45 wt% or less, the zinc content is 10 wt% or more and 30 wt% or less, the total content of nickel and zinc is 55 wt% or more and 65 wt% or less, and the balance is copper And a sputtering target material formed of a copper alloy comprising inevitable impurities. The sputtering target material according to claim 1, wherein the copper is oxygen-free copper. A substrate,
A main conductive layer provided on the substrate and formed of copper,
The wiring laminated body in which the coating layer formed using the sputtering target material of Claim 1 or 2 is provided on the said main conductive layer.

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