阅读说明：本技术 银合金溅射靶以及银合金膜 (Silver alloy sputtering target and silver alloy film ) 是由 岁森悠人 野中荘平 于 2020-01-24 设计创作，主要内容包括：特征在于：含有超过1.0原子％且5.0原子％以下的范围内的镁和超过0.10原子％且2.00原子％以下的范围内的钯,剩余部分由银与不可避免的杂质构成。也可以进一步含有0.10原子％以上的金,并且金与钯的总含量在5.00原子％以下。也可以进一步含有0.01原子％以上且0.15原子％以下的范围内的钙。而且,含氧量也可以为0.010质量％以下。(Is characterized in that: contains magnesium in a range of more than 1.0 atomic% and 5.0 atomic% or less and palladium in a range of more than 0.10 atomic% and 2.00 atomic% or less, with the remainder being composed of silver and unavoidable impurities. The alloy may further contain 0.10 atomic% or more of gold, and the total content of gold and palladium is 5.00 atomic% or less. Calcium may be further contained in a range of 0.01 atomic% to 0.15 atomic%. The oxygen content may be 0.010 mass% or less.)

1. A silver alloy sputtering target characterized by comprising,

contains magnesium in a range of more than 1.0 atomic% and 5.0 atomic% or less and palladium in a range of more than 0.10 atomic% and 2.00 atomic% or less, with the remainder being composed of silver and unavoidable impurities.

2. The silver alloy sputtering target according to claim 1,

further contains 0.10 atomic% or more of gold, and the total content of gold and palladium is 5.00 atomic% or less.

3. The silver alloy sputtering target according to claim 1 or 2,

further contains calcium in a range of 0.01 to 0.15 atomic%.

4. Silver alloy sputtering target according to any one of claims 1 to 3,

the oxygen content is 0.010 mass% or less.

5. A silver alloy film characterized in that,

contains magnesium in a range of more than 1.0 atomic% and 5.0 atomic% or less and palladium in a range of more than 0.10 atomic% and 2.00 atomic% or less, with the remainder being composed of silver and unavoidable impurities.

6. The silver alloy film according to claim 5,

further contains 0.10 atomic% or more of gold, and the total content of gold and palladium is 5.00 atomic% or less.

7. The silver alloy film according to claim 5 or 6,

further contains calcium in a range of 0.01 to 0.15 atomic%.

8. The silver alloy film according to any one of claims 5 to 7,

the oxygen content is 0.010 mass% or less.

Technical Field

The present invention relates to a silver alloy sputtering target and a silver alloy film used for forming a silver alloy film, and the silver alloy film can be suitably used for, for example, a transparent conductive film for a display or a touch panel, a metal thin film for an optical functional film, or the like.

The present application claims priority based on Japanese application No. 2019-020064, 2/6/2019, and the contents thereof are incorporated herein by reference.

Background

For example, in a liquid crystal display, an organic EL display, a touch panel, or the like, as a transparent conductive film constituting a wiring and an electrode, for example, as disclosed in patent documents 1 to 3, a laminated film having a laminated structure of a transparent conductive oxide film and a silver film made of silver or a silver alloy is applied. The multilayer film is required to have high transmittance of light in the visible light region and low resistance.

In addition, when a silver film made of silver or a silver alloy is formed on a glass substrate or the like, a sputtering method using a sputtering target made of silver or a silver alloy is widely used as disclosed in patent document 4, for example.

Patent document 1: japanese patent laid-open publication No. 2006-028641

Patent document 2: japanese laid-open patent publication No. H09-291356

Patent document 3: japanese laid-open patent publication No. 10-239697

Patent document 4: japanese patent laid-open publication No. 2016-040411

However, in the above-described laminated film or silver film, particles, fingerprints, sweat stains, and the like are attached to the film surface or the film end surface, and chlorine (Cl) contained in the particles corrodes the silver film, which may result in poor appearance. Further, corrosion of the silver film may cause poor conduction, and may fail to function as a wiring or an electrode. Even in a laminated film in which a transparent conductive oxide film is formed on a silver film, there is a possibility that chlorine (Cl) penetrates through the transparent conductive oxide film to cause corrosion of the silver film.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a silver alloy sputtering target and a silver alloy film that can suppress corrosion due to chlorine (Cl) and can form a silver alloy film having excellent environmental resistance.

In order to solve the above problem, a silver alloy sputtering target according to an embodiment of the present invention contains magnesium in a range of more than 1.0 atomic% and 5.0 atomic% or less and palladium in a range of more than 0.10 atomic% and 2.00 atomic% or less, and the balance is composed of silver and unavoidable impurities.

In the silver alloy sputtering target having this configuration, since magnesium having a lower free energy of chloride generation than silver is contained in an amount exceeding 1.0 atomic%, when it comes into contact with chlorine (Cl), magnesium preferentially generates chloride. Further, palladium is contained in an amount exceeding 0.10 atomic%, and the palladium is dissolved in silver to suppress the reaction between silver and chlorine (Cl). Therefore, corrosion of the formed silver alloy film by chlorine (Cl) can be suppressed.

Further, since the magnesium content is limited to 5.0 atomic% or less, the resistance value of the silver alloy film formed can be suppressed from increasing, and the conductivity can be ensured.

Further, since the palladium content is limited to 2.00 atomic% or less, deterioration of optical characteristics of the silver alloy film formed can be suppressed, and light transmittance can be ensured.

The silver alloy sputtering target according to the embodiment of the present invention may further contain 0.10 atomic% or more of gold, and the total content of gold and palladium is 5.00 atomic% or less.

In this case, the silver alloy film further contains 0.10 atomic% or more of gold, and the gold is dissolved in silver together with palladium, whereby the reaction between silver and chlorine (Cl) can be further suppressed, and the corrosion of the formed silver alloy film by chlorine (Cl) can be further suppressed.

Further, the palladium content is limited to 2.00 atomic% or less, and the total content of gold and palladium is limited to 5.00 atomic% or less, so that deterioration of optical characteristics of the silver alloy film formed can be suppressed, and light transmittance can be ensured.

The silver alloy sputtering target according to the embodiment of the present invention may further contain calcium in a range of 0.01 atomic% to 0.15 atomic%.

In this case, since calcium having a lower free energy of formation of chloride than silver is contained in an amount of 0.01 atomic% or more, calcium preferentially forms chloride together with magnesium when it comes into contact with chlorine (Cl), and corrosion of the silver alloy film formed can be further suppressed by chlorine (Cl).

Since the calcium content is limited to 0.15 atomic% or less, the occurrence of cracking during processing can be suppressed, and the silver alloy sputtering target can be stably produced.

In the silver alloy sputtering target according to the embodiment of the present invention, the oxygen content is preferably 0.010 mass% or less.

As described above, since the silver alloy sputtering target according to the embodiment of the present invention contains magnesium as an easily oxidizable element in a large amount, magnesium oxide is generated. Since the magnesium oxide is an insulator, it causes abnormal discharge during sputtering film formation. Therefore, by limiting the oxygen content to 0.010 mass% or less, the generation of magnesium oxide can be suppressed, and the occurrence of abnormal discharge during sputter film formation can be suppressed.

The silver alloy film according to the embodiment of the present invention is characterized by containing magnesium in a range of more than 1.0 atomic% and 5.0 atomic% or less and palladium in a range of more than 0.10 atomic% and 2.00 atomic% or less, and the balance being silver and unavoidable impurities.

In the silver alloy film having this structure, magnesium having a lower free energy of chloride formation than silver is contained in an amount exceeding 1.0 atomic%, and therefore, when the film is brought into contact with chlorine (Cl), magnesium preferentially forms chloride. Further, palladium is contained in an amount exceeding 0.10 atomic%, and the palladium is dissolved in silver to suppress the reaction between silver and chlorine (Cl). Therefore, corrosion due to chlorine (Cl) can be suppressed, and the occurrence of appearance defects and conduction defects can be suppressed.

Further, since the magnesium content is limited to 5.0 atomic% or less, the resistance value can be suppressed from increasing, and the conductivity can be ensured.

Further, since the palladium content is limited to 2.00 atomic% or less, deterioration of optical characteristics can be suppressed, and light transmittance can be ensured.

The silver alloy film according to the embodiment of the present invention may further contain 0.10 atomic% or more of gold, and the total content of gold and palladium is 5.00 atomic% or less.

In this case, gold is further contained in an amount of 0.10 atomic% or more, and the gold is dissolved in silver together with palladium, whereby the reaction between silver and chlorine (Cl) can be further suppressed, and corrosion by chlorine (Cl) can be further suppressed.

Also, the palladium content is limited to 2.00 atomic% or less, and the total content of gold and palladium is limited to 5.00 atomic% or less, so that deterioration of optical characteristics can be suppressed, and light transmittance can be ensured.

The silver alloy film according to the embodiment of the present invention may further contain calcium in a range of 0.01 atomic% or more and 0.15 atomic% or less.

In this case, since calcium having a lower free energy of formation of chloride than silver is contained in an amount of 0.01 atomic% or more, when it comes into contact with chlorine (Cl), calcium preferentially forms chloride together with magnesium, and corrosion by chlorine (Cl) can be further suppressed.

Further, since the calcium content is limited to 0.15 atomic% or less, a silver alloy sputtering target used for forming a silver alloy film can be stably produced.

In the silver alloy film according to the embodiment of the present invention, the oxygen content is preferably 0.010 mass% or less.

In this case, since the oxygen content is limited to 0.010 mass% or less, consumption of magnesium by oxygen can be suppressed, and corrosion of silver can be suppressed reliably by magnesium.

According to the present invention, it is possible to provide a silver alloy sputtering target and a silver alloy film that can suppress corrosion due to chlorine (Cl) and can form a silver alloy film having excellent environmental resistance.

Drawings

Fig. 1 is a cross-sectional explanatory view of a laminated film including a silver alloy film according to an embodiment of the present invention.

Fig. 2A is an observation result of the abdominal end portion of the silver alloy film of example 1 of the present invention after the constant temperature and humidity test in the example.

Fig. 2B is an observation result of the film center portion of the silver alloy film of inventive example 1 after the constant temperature and humidity test in the example.

Fig. 3A is an observation result of a film end portion of the silver alloy film of comparative example 1 after the constant temperature and humidity test in the example.

Fig. 3B is an observation result of the film center portion of the silver alloy film of comparative example 1 after the constant temperature and humidity test in the example.

Detailed Description

Hereinafter, a silver alloy sputtering target and a silver alloy film according to an embodiment of the present invention will be described.

The silver alloy sputtering target of the present embodiment is a target used for forming a silver alloy film.

As described above, the silver alloy sputtering target of the present embodiment is a target for forming a silver alloy film by sputtering. The shape of the silver alloy sputtering target is not particularly limited, and the sputtering target may be a rectangular flat plate having a rectangular sputtering surface or a circular plate having a circular sputtering surface. Alternatively, the sputtering surface may be a cylindrical surface.

The silver alloy sputtering target of the present embodiment is composed of a silver alloy containing magnesium in a range of more than 1.0 atomic% and 5.0 atomic% or less and palladium in a range of more than 0.10 atomic% and 2.00 atomic% or less, with the balance being silver and unavoidable impurities.

The silver alloy sputtering target of the present embodiment may further contain 0.10 atomic% or more of gold, and the total content of gold and palladium is 5.00 atomic% or less.

The silver alloy sputtering target according to the present embodiment may further contain calcium in a range of 0.01 atomic% to 0.15 atomic%.

In the silver alloy sputtering target of the present embodiment, the oxygen content is preferably limited to 0.010 mass% or less.

The silver alloy film 11 of the present embodiment is a film used as a thin metal film of a transparent conductive film or an optically functional film of an electronic device such as a touch panel, a solar cell, or an organic EL device.

In the present embodiment, as shown in fig. 1, a transparent conductive film formed of a laminated film 10 is configured.

The laminated film 10 shown in fig. 1 includes a silver alloy film 11 formed on one surface of a substrate 1 made of glass or the like, and transparent conductive oxide films 12 formed on both surfaces of the silver alloy film 11.

In the laminated film 10 shown in fig. 1, the thickness of the silver alloy film is preferably in the range of 5nm to 20 nm. The thickness of the transparent conductive oxide film 12 is preferably in the range of 5nm to 50 nm.

The silver alloy film 11 is a film formed using the silver alloy sputtering target described above, and has the following composition: contains magnesium in a range of more than 1.0 atomic% and 5.0 atomic% or less and palladium in a range of more than 0.10 atomic% and 2.00 atomic% or less, with the balance being silver and unavoidable impurities.

The silver alloy film 11 of the present embodiment may further contain 0.10 atomic% or more of gold, and the total content of gold and palladium is 5.00 atomic% or less.

The silver alloy film 11 of the present embodiment may further contain calcium in a range of 0.01 atomic% to 0.15 atomic%.

In addition, the silver alloy film 11 of the present embodiment is preferably limited to an oxygen content of 0.010 mass% or less.

The transparent conductive oxide film 12 is made of, for example, a transparent conductive oxide containing one or two or more selected from indium oxide, tin oxide, zinc oxide, niobium oxide, titanium oxide, aluminum oxide, and gallium oxide. Specifically, there may be mentioned In-Sn oxide (ITO), Al-Zn oxide (AZO), In-Zn oxide (IZO), Zn-Sn oxide (ZTO), Zn-Sn-Al oxide (AZTO), Ga-Zn oxide (GZO), Zn-Y oxide (ZYO), Ga-Zn-Y oxide (GZYO) and the like.

The composition of the transparent conductive oxide film 12 is preferably selected as appropriate in accordance with the required characteristics.

The reason why the composition of the silver alloy sputtering target and the silver alloy film 11 of the present embodiment is determined as described above will be described.

(magnesium: Mg)

Magnesium is an element that has lower free energy for chloride formation than silver and readily forms chloride. Therefore, by containing magnesium, chlorine (Cl) and magnesium can be preferentially reacted, thereby suppressing corrosion of silver.

When the magnesium content is 1.0 atomic% or less, the above-mentioned effects may not be sufficiently obtained. On the other hand, when the magnesium content exceeds 5.0 atomic%, the resistance value of the formed silver alloy film may increase, and the conductivity may decrease.

For this reason, in the present embodiment, the magnesium content is set to be in a range of more than 1.0 atomic% and 5.0 atomic% or less.

In order to further suppress corrosion of silver by chlorine (Cl), the lower limit of the magnesium content is preferably 1.5 atomic% or more, and more preferably 2.0 atomic% or more. On the other hand, in order to further suppress an increase in the resistance value of the formed silver alloy film, the upper limit of the magnesium content is preferably 4.5 atomic% or less, and more preferably 4.0 atomic% or less.

(Palladium: Pd)

Palladium is an element having an effect of suppressing a reaction of silver with chlorine (Cl) by being solid-dissolved in a mother phase of silver.

When the palladium content is 0.10 atomic% or less, the above-mentioned effects may not be sufficiently obtained. On the other hand, when the palladium content exceeds 2.00 atomic%, the optical characteristics of the silver alloy film formed may deteriorate, and the transmittance may be low.

For this reason, in the present embodiment, the palladium content is set to be in a range of more than 0.10 atomic% and 2.00 atomic% or less.

In order to further suppress the reaction of chlorine (Cl) with silver and further suppress the corrosion of silver, the lower limit of the amount of palladium is preferably 0.50 atomic% or more, and more preferably 1.00 atomic% or more. On the other hand, in order to further suppress the deterioration of the optical characteristics of the silver alloy film formed, the upper limit of the palladium content is preferably 1.80 atomic% or less, and more preferably 1.50 atomic% or less.

(gold: Au)

Gold is an element having an effect of suppressing the reaction between silver and chlorine (Cl) by being solid-dissolved in a mother phase of silver, similarly to palladium.

By setting the gold content to 0.10 atomic% or more, corrosion of silver by chlorine (Cl) can be further suppressed. On the other hand, by limiting the total content of gold and palladium to 5.00 atomic% or less and limiting the content of palladium to 2.00 atomic%, it is possible to suppress deterioration of optical characteristics of the silver alloy film formed, and maintain a high transmittance.

For this reason, in the case where gold is added in the present embodiment, the gold content is set to 0.10 atomic% or more, and the total content of gold and palladium is set to 5.00 atomic% or less.

In order to further suppress the reaction between chlorine (Cl) and silver and further suppress the corrosion of silver, the gold content is preferably 0.50 atomic% or more, and more preferably 1.00 atomic% or more. On the other hand, in order to further suppress deterioration of optical characteristics of the silver alloy film formed, the total content of gold and palladium is preferably 4.50 atomic% or less, and more preferably 4.00 atomic% or less.

In the case where gold is not intentionally added, the gold content may be less than 0.10 atomic%.

(calcium: Ca)

Calcium is an element which has a lower free energy for chloride formation than silver and which easily forms chloride, as with magnesium. Therefore, by containing calcium, chlorine (Cl) and magnesium can be preferentially reacted, thereby further suppressing corrosion of silver.

By setting the calcium content to 0.01 atomic% or more, corrosion of silver by chlorine (Cl) can be further suppressed. On the other hand, by limiting the calcium content to 0.15 atomic% or less, workability can be ensured and the occurrence of cracking during working can be suppressed.

For this reason, when calcium is added in the present embodiment, the calcium content is preferably set to be in the range of 0.01 atomic% or more and 0.15 atomic% or less.

In order to further suppress the reaction between chlorine (Cl) and silver and further suppress the corrosion of silver, the lower limit of the calcium content is preferably 0.02 at% or more, and more preferably 0.05 at% or more. On the other hand, in order to further ensure workability and further suppress the occurrence of cracking during working, the upper limit of the calcium content is preferably 0.13 atomic% or less, and more preferably 0.10 atomic% or less.

In the case where calcium is not intentionally added, the calcium content may be less than 0.01 atomic%.

(oxygen content)

In the silver alloy sputtering target of the present embodiment, when the oxygen content is limited to 0.010 mass% or less, the oxidation of magnesium, which is an easily oxidizable element, can be suppressed, and the generation of magnesium oxide, which is an insulator, can be suppressed. This can suppress the occurrence of abnormal discharge during sputter deposition, and can stably form a silver alloy film. Further, the consumption of magnesium as an oxide can be suppressed, and the corrosion of silver can be surely suppressed by magnesium.

For this reason, in the present embodiment, it is preferable to limit the oxygen content to 0.010 mass% or less.

In order to further suppress the generation of magnesium oxide and to suppress the generation of abnormal discharge during sputter deposition, the oxygen content is preferably 0.008 mass% or less, and more preferably 0.005 mass% or less.

Further, the lower limit of the oxygen content is not particularly limited, but industrially less than 0.001 mass% is not preferable because the production cost is greatly increased.

Next, a method for manufacturing the silver alloy sputtering target of the present embodiment will be described.

First, a silver raw material having a purity of 99.9 mass% or more and palladium and magnesium auxiliary raw materials having a purity of 99.9 mass% or more are prepared. Further, gold and calcium auxiliary raw materials having a purity of 99.9 mass% or more are prepared as necessary.

Next, the silver raw material is melted in a melting furnace under high vacuum or in an inert gas atmosphere, and a predetermined amount of auxiliary raw materials (palladium and magnesium, and, if necessary, gold and calcium) are added to the obtained silver melt to obtain a silver alloy melt. Thereafter, the silver alloy melt is supplied to a mold to obtain a silver alloy ingot having a predetermined composition.

In order to reduce the oxygen content in the silver alloy ingot, it is preferable that the inside of the melting furnace is once brought into a high vacuum (5 × 10) for melting the silver raw material^-2Pa or less), the substitution with an inert gas (argon or nitrogen) is repeated three or more times until the atmospheric pressure is around, and then the silver raw material is melted preferably in an inert gas atmosphere, and then the auxiliary raw material is charged. The auxiliary raw materials (palladium and magnesium, and, if necessary, gold and calcium) may be added as a previously prepared master alloy (for example, silver-calcium alloy).

Next, the obtained silver alloy ingot was cold worked. The cumulative rolling reduction at this time is preferably 70% or more.

Next, the obtained cold worked material was subjected to a heat treatment in an atmospheric atmosphere at a heat treatment temperature: a retention time at a heat treatment temperature of 500 ℃ to 700 ℃ inclusive: the heat treatment is performed for 1 hour or more and 5 hours or less.

The obtained heat-treated material is then subjected to machining such as cutting, and is finished into a predetermined shape and size.

The silver alloy sputtering target of the present embodiment is manufactured by the above-described steps.

Next, a method for producing the silver alloy film of the present embodiment will be described.

The silver alloy film of the present embodiment is formed by using the silver alloy sputtering target of the present embodiment described above.

The silver alloy sputtering target of the present embodiment is formed by, for example, soldering to a back plate material made of oxygen-free copper, and mounting the back plate material on a sputtering apparatus to perform sputtering, thereby forming a silver alloy film on the surface of a substrate.

The sputtering apparatus used may be a stationary opposed type In which the substrate on which the silver alloy film is formed is stationary and sputtering is performed, or a substrate transport type (In Line) In which the substrate is transported and sputtering is performed.

As a power source of the sputtering apparatus, for example, a Direct Current (DC) power source, a high frequency (RF) power source, an intermediate frequency (MF) power source, or an Alternating Current (AC) power source can be used.

According to the silver alloy sputtering target and the silver alloy film 11 of the present embodiment having the above-described configurations, since magnesium having a lower free energy of chloride formation than silver is contained in an amount exceeding 1.0 atomic%, when it comes into contact with chlorine (Cl), magnesium preferentially forms chloride. Further, palladium is contained in an amount exceeding 0.10 atomic%, and the palladium is dissolved in silver to suppress the reaction between silver and chlorine (Cl). Therefore, corrosion of the silver alloy film 11 by chlorine (Cl) can be suppressed.

Further, since the magnesium content is limited to 5.0 atomic% or less, the resistance value of the silver alloy film 11 can be suppressed from increasing, and the conductivity can be ensured.

Further, the palladium content is limited to 2.00 atomic% or less, so that deterioration of the optical characteristics of the silver alloy film 11 can be suppressed, and light transmittance can be secured.

In the present embodiment, when gold is further contained in an amount of 0.10 atomic% or more and the total content of gold and palladium is 5.00 atomic% or less, the gold is dissolved in silver together with palladium to further suppress the reaction between silver and chlorine (Cl), thereby further suppressing corrosion of the silver alloy film 11 formed by the film formation by chlorine (Cl).

On the other hand, the palladium content is limited to 2.00 atomic% or less, and the total content of gold and palladium is limited to 5.00 atomic% or less, and therefore, deterioration of the optical characteristics of the silver alloy film 11 formed can be suppressed, so that the light transmittance can be ensured.

In the present embodiment, when calcium is further contained in the range of 0.01 atomic% or more and 0.15 atomic% or less, the calcium preferentially generates chloride together with magnesium when contacting chlorine (Cl), and corrosion of the silver alloy film 11 by chlorine (Cl) can be further suppressed.

On the other hand, since the calcium content is limited to 0.15 atomic% or less, the occurrence of cracking during processing can be suppressed, and the silver alloy sputtering target can be stably produced.

In the present embodiment, when the oxygen content is further limited to 0.010 mass% or less, the oxidation of magnesium, which is an easily oxidizable element, is suppressed, whereby the generation of magnesium oxide, which is an insulator, can be suppressed, and the occurrence of abnormal discharge during sputter film formation can be suppressed.

Further, the consumption of magnesium by oxygen can be suppressed, and the corrosion of silver can be surely suppressed by magnesium.

The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and can be modified as appropriate within a range not departing from the technical spirit of the present invention.

For example, as shown in fig. 1, in the present embodiment, a silver alloy film constituting a laminated film is described, but the present invention is not limited thereto, and the silver alloy film of the present invention may be a film used as a single film.

In the present embodiment, the description has been given of the mode of manufacturing the sputtering target by cold-rolling the silver alloy ingot, but the present invention is not limited to this, and other manufacturing methods may be applied. As for the production method, a known method is preferably selected as appropriate according to the shape of the silver alloy sputtering target to be produced.

Examples

Hereinafter, the results of a confirmation experiment for confirming the effectiveness of the present invention will be described using examples of the present invention.

< silver alloy sputtering target >

Silver raw materials having a purity of 99.9 mass% or more and auxiliary raw materials of palladium and magnesium (gold and calcium) having a purity of 99.9 mass% or more are prepared and weighed so as to have a predetermined mixing ratio.

Next, the silver raw material is melted in a melting furnace under high vacuum or in an inert gas atmosphere, and an auxiliary raw material (palladium, magnesium, gold, calcium) is added to the obtained silver melt to prepare a silver alloy melt. Then, the silver alloy melt is supplied to a mold to obtain a silver alloy ingot having a predetermined composition.

In the melting of the silver raw material, the inside of the melting furnace is once evacuated to a high vacuum (5)×10^-2Pa or less), replacement with an inert gas (argon or nitrogen) was repeated three times until the atmospheric pressure was around. Then, the silver raw material is melted in an inert gas atmosphere, and then the auxiliary raw material is charged.

Next, the obtained silver alloy ingot was cold-rolled at a reduction ratio of 80%, and then heat-treated at 600 ℃ for 1 hour in the air.

Then, a silver alloy sputtering target having a predetermined size (126 mm. times.178 mm, thickness 6mm) was obtained by machining.

(composition of silver alloy sputtering target)

A measurement sample was collected from the obtained silver alloy ingot, and analyzed by ICP emission spectrometry. The measurement of the oxygen content was carried out by an inert gas melting-infrared absorption method (JIS H1067). The measurement results are shown in table 1.

(number of abnormal discharges)

Exhausting the interior of the sputtering apparatus to 5X 10^-5After Pa, at argon pressure: 0.5Pa, input power: dc 1000W, distance between target substrates: sputtering was carried out under a condition of 70 mm. The number of abnormal discharges during sputtering was measured for 6 hours from the start of discharge by the arc counting function of a DC power supply (RPDG-50A) manufactured by MKS Instruments. The measurement results are shown in table 1.

< silver alloy film >

Next, a laminated film was formed using the silver alloy sputtering target obtained in the above manner as follows.

First, a glass substrate of 10cm × 30cm (EAGLEXG, Corning) was prepared as a substrate.

Further, as a sputtering target for forming a transparent conductive oxide film, ITO (In) was prepared₂O₃-10 mass% SnO₂) The sputtering target is formed.

The sputtering target and the silver alloy sputtering target were welded to a backing plate made of oxygen-free copper, and the backing plate was mounted on a sputtering apparatus. In the present embodiment, a magnetron DC sputtering apparatus is used. In the present embodiment, a substrate transport type sputtering apparatus is used which carries a substrate and performs sputtering.

Next, sputtering was performed under the following conditions to form a transparent conductive oxide film and a silver alloy film on the substrate, thereby obtaining a laminated film having a layer structure shown in table 2.

Film formation starting vacuum degree: 7.0X 10^-4Pa or less

Sputtering gas: high purity argon

Sputtering gas pressure in the chamber: 0.4Pa

Direct current power: 100W

(composition of silver alloy film)

According to the above conditions, a metal film having a thickness of 1000nm was formed on a glass substrate, and the composition was measured by ICP emission spectroscopy. The measurement of the oxygen content was carried out by an inert gas melting-infrared absorption method (JIS H1067). As a result, it was confirmed that the composition of the silver alloy film was the same as that of the silver alloy sputtering target used.

(measurement of film thickness)

When film formation is performed by sputtering, the film thickness is measured for a certain time after film formation by a step profiler (DEKTAK-XT) to measure the sputtering rate, and film formation is performed so that the film formation time is adjusted based on the value to form a target thickness.

The actual film thickness of the laminated film was confirmed by observing the cross section of the laminated film with a Transmission Electron Microscope (TEM), and the film formed with the film thickness satisfying the target value was confirmed. For the preparation of a sample for TEM observation, for example, a cross-section ion polisher (CP) or a Focused Ion Beam (FIB) can be used.

(evaluation of Electrical characteristics of laminated film)

The sheet resistance of the laminated film was measured by a four-probe method using a resistance measuring instrument Loresta-GP manufactured by Mitsubishi chemical. The evaluation results are shown in table 2.

(evaluation of optical Properties of laminated film)

The transmittance of the laminated film was measured using a spectrophotometer (U-4100 manufactured by Hitachi High-Tech Corporation). The evaluation results are shown in table 2. The average transmittance at a wavelength of 380nm to 780nm is shown in Table 2.

(evaluation of environmental resistance of laminated film)

The laminated film was held in a constant temperature and humidity chamber at a temperature of 85 ℃ and a humidity of 85% for 250 hours, and the appearance of the film after the test was observed with an optical microscope to determine the presence or absence of discoloration (appearance defect). The evaluation results are shown in table 2. Fig. 2A to 2B and fig. 3A to 3B show examples of observation of the laminated film after the constant temperature and humidity test. Fig. 2A is an observation result of the abdominal end portion of the silver alloy film of inventive example 1, and fig. 2B is an observation result of the film center portion of the silver alloy film of inventive example 1. Fig. 3A is an observation result of the film end portion of the silver alloy film of comparative example 1, and fig. 3B is an observation result of the film center portion of the silver alloy film of comparative example 1.

The discoloration occurs by accelerating corrosion due to chlorine (Cl) contained in particles adhering to the laminated film by a constant temperature and humidity test.

[ Table 1]

[ Table 2]

In the laminated film of comparative example 101 having the silver alloy film formed using the silver alloy sputtering target of comparative example 1 containing 0.08 atomic% of palladium, as shown in fig. 3A to 3B, a discolored portion was observed in the silver alloy film after the constant temperature and humidity test. This is presumably because the corrosion-inhibiting effect of palladium is insufficient and corrosion due to chlorine (Cl) occurs.

The transmittance was low in the laminated film of comparative example 102 having the silver alloy film formed using the silver alloy sputtering target of comparative example 2 containing 3.00 atomic% of palladium.

In the laminated film of comparative example 103 having the silver alloy film formed using the silver alloy sputtering target of comparative example 3 containing 0.08 atomic% of magnesium, a discolored portion was observed in the silver alloy film after the constant temperature and humidity test. This is presumably because the corrosion-inhibiting effect of magnesium is insufficient and corrosion due to chlorine (Cl) occurs.

The laminated film of comparative example 104 having the silver alloy film formed using the silver alloy sputtering target of comparative example 4 containing 7.2 atomic% of magnesium had a high sheet resistance.

The transmittance was low in the laminated film of comparative example 105 having the silver alloy film formed using the silver alloy sputtering target of comparative example 5 in which the total content of gold and palladium was 7.00 atomic%.

In comparative example 6 having a calcium content of 0.21 atomic%, cracking occurred during rolling, and a sputtering target could not be produced. Therefore, the subsequent evaluation was suspended.

In contrast, in the laminated films of invention examples 101 to 112 having silver alloy films formed using the silver alloy sputtering targets of invention examples 1 to 12 containing magnesium in a range of more than 1.0 atomic% and 5.0 atomic% or less and palladium in a range of more than 0.10 atomic% and 2.00 atomic% or less, for example, as shown in fig. 2A to 2B, no discolored portion was observed in the silver alloy films after the constant temperature and humidity test. It was confirmed that corrosion due to chlorine (Cl) was suppressed by the corrosion suppressing effect of magnesium and gold.

Further, it was confirmed that the film resistance was very low, the average transmittance was very high, and the film was excellent in electrical and optical properties and suitable as a transparent conductive film.

In inventive examples 6, 7, 8 and 11, 0.10 atomic% or more of gold was contained, and the total content of gold and palladium was 5.00 atomic%, and corrosion after the constant temperature and humidity test was not observed, and the electrical characteristics and the optical characteristics were excellent.

In addition, in inventive examples 9 to 11, calcium was contained in a range of 0.01 atomic% or more and 0.15 atomic% or less, and corrosion was not observed after the constant temperature and humidity test, and the electrical and optical characteristics were excellent.

Further, the silver alloy sputtering targets of examples 1 to 11 of the present invention, in which the oxygen content was 0.010 mass% or less, can sufficiently suppress the occurrence of abnormal discharge during sputter film formation, and can stably sputter film formation.

In the silver alloy sputtering target of invention example 12 containing 0.032 mass% of oxygen, although abnormal discharge occurred during sputtering film formation, film formation of a silver alloy film could be achieved. Further, the laminated film of example 112 of the present invention, which had the silver alloy film formed by using the silver alloy sputtering target of example 12 of the present invention, was also very excellent in environmental resistance as compared with the comparative example.

As described above, according to the present invention, it has been confirmed that a silver alloy sputtering target and a silver alloy film can be provided which can suppress corrosion due to chlorine (Cl) and can form a silver alloy film having excellent environmental resistance.

Industrial applicability

According to the present invention, it is possible to provide a silver alloy sputtering target and a silver alloy film that can suppress corrosion due to chlorine (Cl) and can form a silver alloy film having excellent environmental resistance.