TW201710515A - Cu alloy sputtering target - Google Patents

Abstract

A Cu alloy, which has a composition including: 5 mass% or more and 15 mass% or less of Ni or Ni and Al, Ni being 0.5 mass % or more; 0.1 mass% or more and 5.0 mass% or less of Mn; 0.5 mass% or more and 7.0 mass% or less of Fe; and the Cu balance including inevitable impurities, wherein the maximum grain size of non-metallic inclusion bodies is 10 [mu]m or less, is provided.

Description

Copper alloy sputtering target

The present invention relates to a copper alloy sputtering target which is a film for forming a copper alloy film which is used as a protective film for a flat panel display or a wiring film of a touch panel or a wiring film, which has excellent weather resistance.

The present application claims priority to Japanese Patent Application No. 2015-091661, the entire disclosure of which is incorporated herein by reference.

Conventionally, Al has been widely used as a flat panel display such as a liquid crystal or an organic EL panel, or a wiring film such as a touch panel. Recently, in order to reduce the thickness (narrowing) and thinning of the wiring film, a wiring film having a lower specific impedance than the prior art has been required.

With the miniaturization and thinning of the wiring film described above, a wiring film of copper or a copper alloy using a material having a lower specific resistance than Al is provided.

However, a Cu wiring film composed of copper or a copper alloy having a lower specific resistance has a problem that it is easily discolored in an environment having humidity.

Therefore, for example, Patent Document 1 is proposed on the Cu wiring film. A laminated film of a protective film composed of a Ni-Cu-(Cr, Ti) alloy and a sputtering target for forming the protective film are formed. This protective film has higher weather resistance than copper, and it can suppress discoloration of the surface even when it is stored in the atmosphere. Further, it is considered that the copper alloy film itself is used as a wiring film.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2012-193444 (A)

However, when the copper alloy film is formed by using the sputtering target described in Patent Document 1, abnormal discharge and splashing occur depending on the sputtering conditions, and there is a problem that film formation cannot be performed satisfactorily. In particular, when a large-sized sputtering target is used, since a large electric power is input, micro-arc discharge is likely to occur, and the sputtering target is partially melted to generate particles, and the copper alloy film cannot be formed into a good film. doubt. In addition, the same applies to the case where large electric power is input in order to improve the film forming efficiency.

Further, the sputtering target is produced, for example, by a step of casting or hot rolling. However, if cracking occurs during hot rolling, abnormal discharge occurs in the cracked portion, and thus it cannot be used as a sputtering target.

The enlargement of the glass substrate in which the wiring film has recently been formed is progressing, and as a result, the sputtering target itself tends to increase in size. Here, in manufacturing In the case of a large sputtering target, if a part of the hot rolled material is broken, it becomes impossible to obtain a sputtering target of a specific size. Therefore, in order to efficiently produce a large sputtering target, it is required to have excellent hot workability.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a copper alloy sputtering target which can form a copper alloy film excellent in weather resistance, can suppress occurrence of abnormal discharge during film formation, and simultaneously has hot workability. Excellent.

In order to solve the above problems, a copper alloy sputtering target (hereinafter referred to as "the copper alloy sputtering target of the present invention") of the present invention is characterized in that it contains Ni, or a total of Ni and Al is 5 mass% or more. 15 mass% or less (however, it contains Ni 0.5 mass% or more), and contains Mn 0.1 mass% or more and 5.0 mass% or less, and contains Fe 0.5 mass% or more and 7.0 mass% or less, and the remainder is composed of Cu and unavoidable impurities. The composition of the non-metallic inclusions has a maximum particle diameter of 10 μm or less.

In the copper alloy sputtering target of the present invention, since the maximum particle diameter of the non-metallic inclusions is limited to 10 μm or less, it is possible to prevent the non-metallic inclusions from accumulating electric charges and causing abnormal discharge when the film is formed by sputtering. Sputtering film formation can be carried out stably.

In general, non-metallic inclusions are oxides, nitrides, sulfides, carbides, niobates, etc., but in the copper alloy target of the present invention, non-metallic inclusions other than oxides are hardly detected, so The maximum particle size of the non-metallic inclusions which are substantially oxides is a problem. In addition, as oxygen The compound (non-metallic inclusion) contains an alloy of Cu, Ni, Al, Mn, an oxide of Fe, or an oxide contained as an impurity.

In addition, the copper alloy sputtering target of the present invention contains Ni, or Ni and Al in total of 5 mass% or more and 15 mass% or less (however, contains Ni 0.5 mass% or more), and contains Mn 0.1 mass% or more and 5.0 mass% or less, and contains Fe is 0.5 mass% or more and 7.0 mass% or less, and the remainder has a composition composed of Cu and unavoidable impurities. Therefore, the weather resistance of the formed copper alloy film is high, and discoloration of the copper alloy film can be suppressed.

Further, since the total content of Ni, the content of Ni, and the content of Al is less than 15 mass%, the hot workability and the machinability are excellent, and the copper alloy sputtering target can be produced with good yield. Further, since the content of Ni is set to 0.5 mass% or more, the hot rolling property can be improved, and the occurrence of cracking during hot rolling can be suppressed.

Further, since Al is an element which is selectively added in place of one part of Ni, it may be appropriately added in accordance with the content of Ni. In other words, when the content of Ni is 5 mass% or more, Al may not be added, and if the total content of Al and the content of Ni are in the range of 5 mass% or more and 15 mass% or less, Al may be added as necessary. .

Here, in the copper alloy sputtering target of the present invention, the average crystal grain size of the sputtering surface is preferably 50 μm or less.

Since the sputtering rate differs depending on the crystal orientation, when sputtering is performed, irregularities are generated on the sputtering surface due to the difference in the sputtering rate described above. When the particle size of the crystal grain on the sputtering surface is large, the unevenness is increased, and the charge in the convex portion is concentrated. It becomes easy to generate abnormal discharge. Therefore, the average crystal grain size on the sputtering surface is limited to 50 μm or less, and the occurrence of abnormal discharge can be further suppressed.

Further, in the copper alloy sputtering target of the present invention, it is preferable that the Vickers hardness of the sputtering surface is in the range of 60 Hv or more and 120 Hv or less.

In this case, since the Vickers hardness of the sputtering surface is limited to 120 Hv or less, the internal strain in the crystal grain is small, the release of the sputtered particles becomes uniform, and the film thickness of the film-formed copper alloy film can be uniform. improve. Further, by reducing the internal strain and making the sputtering rate uniform, it is possible to suppress the occurrence of irregularities on the sputtering surface during the sputtering process, and it is possible to suppress the occurrence of abnormal discharge.

On the other hand, since the Vickers hardness of the sputtering surface is 60 Hv or more, the crystal grain size can be made small, and it is possible to suppress the occurrence of irregularities on the sputtering surface during the sputtering process, and it is possible to suppress the occurrence of abnormal discharge.

According to the present invention, it is possible to provide a copper alloy sputtering target which can form a copper alloy film excellent in weather resistance, can suppress occurrence of abnormal discharge during film formation, and is excellent in hot workability.

Hereinafter, a copper alloy sputtering target according to an embodiment of the present invention will be described in detail.

For example, a film forming a wiring film such as a flat panel display or a touch panel, or a film formed on a Cu wiring film made of copper or a copper alloy. The copper alloy sputtering target of this embodiment is used for the film of a protective film.

Further, the copper alloy sputtering target of the present embodiment has a flat plate shape, and the area of the sputtering surface is a large-sized sputtering target of 100,000 mm ² or more.

The copper alloy sputtering target of the present embodiment contains Ni, or Ni and Al in total of 5 mass% or more and 15 mass% or less (however, contains Ni 0.5 mass% or more), and contains Mn 0.1 mass% or more and 5.0 mass% or less, and contains Fe. 0.5 mass% or more and 7.0 mass% or less, and the remainder has a composition composed of Cu and unavoidable impurities.

Then, in the copper alloy sputtering target of the present embodiment, the maximum particle diameter of the unavoidable non-metallic inclusions contained in the copper alloy sputtering target is 10 μm or less. In the present embodiment, as the non-metallic inclusion system, an oxide of Cu, Ni, Al, Mn, Fe containing an alloy component or an oxide contained as an impurity is targeted.

Further, the average crystal grain size on the sputtering surface is 50 μm or less, and the Vickers hardness of the sputtering surface is in a range of 60 Hv or more and 120 Hv or less.

Further, in the present embodiment, the surface roughness of the sputtering surface is set to 5 μm or less at the maximum height Rz (JIS B0601-2001).

Next, the reason why the composition of the copper alloy sputtering target of the present embodiment, the size of the non-metallic inclusions, the average crystal grain size, the hardness, and the surface roughness of the sputtering surface are defined as described above will be described.

(Total content of Ni or content of Ni and content of Al: 5 mass% or more and 15 mass% or less)

The Ni-based element has an effect of improving the weather resistance of Cu. By The inclusion of Ni makes it possible to suppress discoloration of the already formed copper alloy film.

Like the Ni, the Al system has an element which has an effect of improving the weather resistance of Cu. Even if Al is added as an alternative to Ni, the discoloration of the film-formed copper alloy film can be suppressed. Further, since the Al-based phase is a relatively inexpensive element compared to Ni, the addition of Al as a substitute for Ni can reduce the cost, and therefore can be added as necessary.

Here, when the total content of Ni, the content of Ni, and the content of Al is less than 5 mass%, the weather resistance cannot be sufficiently improved, and there is a fear that the discoloration of the formed copper alloy film cannot be sufficiently suppressed. On the other hand, when the total content of Ni, the content of Ni, and the content of Al is more than 15 mass%, hot workability and machinability are lowered, and it is difficult to manufacture the copper alloy sputtering target.

For this reason, the total content of Ni, the content of Ni, and the content of Al are set in a range of 0.5 mass% or more and 15 mass% or less.

Though it is not particularly limited, the total content of Ni, the content of Ni, and the content of Al is preferably 6 mass% or more and 14 mass% or less, and more preferably 8 mass% or more and 12 mass% or less.

(Ni: 0.5 mass% or more)

When Ni is added in an appropriate amount, the hot workability is improved.

Here, when the content of Ni is less than 0.5 mass%, the hot workability cannot be sufficiently improved, and cracking occurs during hot rolling, and in particular, a large copper alloy having an area where it is difficult to manufacture a sputtering surface is set to 100000 mm ² or more. Spilled target concerns.

For this reason, the content of Ni is set to 0.5 mass% or more.

Although it is not particularly limited, the content of Ni described above is preferably 1 mass% or more and 14 mass% or less, and more preferably 8 mass% or more and 12 mass% or less.

(Mn: 0.1 mass% or more and 5.0 mass% or less)

Mn is an element which has an effect of improving hot workability by improving the fluidity of the melt.

Here, when the content of Mn is less than 0.1 mass%, the fluidity of the melt is not sufficiently improved, and cracking occurs during hot rolling, and it is not possible to manufacture a large-sized sputtering target with good yield. On the other hand, when the content of Mn exceeds 5.0 mass%, coarse non-metal oxides such as Mn oxide are likely to be generated, and there is a fear that the number of micro-arc discharges is increased.

For this reason, the content of Mn is set to be in the range of 0.1 mass% or more and 5.0 mass% or less.

Although it is not particularly limited, the content of Mn described above is preferably 0.3 mass% or more and 3.0 mass% or less, and more preferably 0.5 mass% or more and 2.0 mass% or less.

(Fe: 0.5 mass% or more and 7.0 mass% or less)

The Fe system has an effect of improving the hot workability by refining the metal structure.

Here, when the content of Fe is less than 0.5 mass%, the hot workability due to the refinement of the metal structure cannot be sufficiently improved, and cracking occurs during hot rolling, and in particular, the area of the sputter surface cannot be set. A large-scale copper alloy sputtering target of 100,000 mm ² or more is manufactured with a good yield. On the other hand, when the content of Fe exceeds 7.0 mass%, there is a concern that the hot workability and the weather resistance are deteriorated.

For this reason, the content of Fe is set to be in the range of 0.5 mass% or more and 7.0 mass% or less.

Although it is not particularly limited, the content of Fe described above is preferably 0.7 mass% or more and 5.0 mass% or less, and more preferably 1.0 mass% or more and 4.0 mass% or less.

(Maximum particle size of non-metallic inclusions: 10μm or less)

The unavoidable non-metallic inclusions contained in the copper alloy sputtering target are presumed to be part of the oxide of the element constituting the copper alloy or the refractory of the melting furnace, and are caught in the ingot during casting and remain. Since these oxides (non-metallic inclusions) are easy to emit secondary electrons, if the maximum particle diameter of the non-metallic inclusions exceeds 10 μm, the amount of secondary electrons is increased, and the number of occurrences of micro-arc discharge is increased. doubt.

For this reason, in the present embodiment, the maximum particle diameter of the unavoidable non-metallic inclusions contained in the copper alloy sputtering target is limited to 10 μm or less.

In order to reliably suppress the micro-arc discharge and to perform the sputtering film formation stably, the maximum particle diameter of the non-metallic inclusions is preferably 5 μm or less, and more preferably 2 μm or less.

Although it is not particularly limited, the lower limit of the maximum particle diameter of the above non-metallic inclusions is 0.8 μm or more.

(average crystal grain size of the sputtered surface: 50 μm or less)

Since the sputtering rate differs depending on the crystal orientation, when the sputtering is performed, irregularities accompanying the crystal grains are generated on the sputtering surface due to the difference in the sputtering rate described above.

When the average crystal grain size exceeds 50 μm, the unevenness generated on the sputtering surface is increased, and the electric charge in the convex portion is concentrated to cause abnormal discharge.

For this reason, in the copper alloy sputtering target of the present embodiment, the average crystal grain size on the sputtering surface is set to 50 μm or less.

In order to suppress the abnormality of the sputtering surface during the sputtering, and to suppress the abnormal discharge, the average crystal grain size on the sputtering surface is preferably 40 μm or less, and more preferably 30 μm or less.

Although it is not particularly limited, the lower limit of the average crystal grain size of the above-mentioned sputtering surface is 18 μm or more.

(Vickers hardness of sputtered surface: 60Hv or more and 120Hv or less)

In the copper alloy sputtering target of the present embodiment, when the Vickers hardness of the sputtering surface exceeds 120 Hv, the internal strain in the crystal grains becomes large, and the sputtering particles are released, and the copper alloy film is formed. The film thickness becomes uneven. Further, the sputtering rate becomes uneven due to internal strain, and irregularities are generated on the sputtering surface, and there is a fear that the number of micro-arc discharges increases. On the other hand, the Vickers hardness of the sputtered surface is less than 60 Hv because the crystal grain size is coarse. Since it is enlarged, the unevenness of the sputtering surface occurs at the time of sputtering, and abnormal discharge is likely to occur.

For this reason, in the copper alloy sputtering target of the present embodiment, the Vickers hardness on the sputtering surface is set to be in the range of 60 Hv or more and 120 Hv or less.

In order to suppress the abnormal crystal discharge, the lower limit of the Vickers hardness of the sputtering surface is preferably 70 Hv or more, and more preferably 75 Hv or more. In addition, it is preferable that the upper limit of the Vickers hardness of the sputtering surface is 100 Hv or less, and it is preferable to set it as 90 Hv or less in order to suppress the film thickness and the micro-arc discharge.

(Surface roughness (maximum height Rz) of the sputtered surface: 5 μm or less)

In the copper alloy sputtering target of the present embodiment, when the surface roughness of the sputtering surface exceeds 5 μm at the maximum height Rz, the front end of the convex portion protruding from the sputtering surface after the use of the copper alloy sputtering target is started The charge is concentrated and there is a concern that an abnormal discharge is likely to occur.

For this reason, in the copper alloy sputtering target of the present embodiment, the surface roughness of the sputtering surface is set to 5 μm or less at the maximum height Rz.

In order to suppress the occurrence of the abnormal discharge after the start of use, the surface roughness of the sputtering surface is preferably 2 μm or less at the maximum height Rz, and more preferably 1 μm or less.

There is no particular limitation, but the lower limit of the surface roughness of the above-mentioned sputtered surface The value is 0.8 μm or more.

Next, an example of a method for producing the copper alloy sputtering target of the present embodiment will be described.

The copper alloy sputtering target of the present embodiment is produced through a step of a melt casting step, a hot rolling step, a (leveling processing step, a cold rolling step, a heat treatment step), and a machining step. Hereinafter, each step will be described.

(melting casting step)

First, the molten raw material is weighed in such a manner as to become the target composition described above. As the raw material for melting, oxygen-free copper having a purity of 99.99 mass% or more, Ni having a purity of 99.9 mass% or more, Al having a purity of 99.99 mass% or more, Fe having a purity of 99.95 mass% or more, and Mn having a purity of 99.9 mass% or more are preferable.

Further, in order to homogenize the alloy elements sufficiently to homogenize the composition of the melt, it is preferable to use an induction melting furnace.

Here, since the alloying elements of Al, Ni, Fe, and Mn are more easily oxidized than Cu, it is possible to suppress the occurrence of coarse non-metallic inclusions by preventing oxidation of these alloying elements during dissolution. .

In order to prevent oxidation during melting, it is desirable to melt in a vacuum environment or an inert gas atmosphere. Further, in the case where it is melted in the atmosphere in consideration of productivity, it is preferable to coat the liquid surface by using a graphite crucible or carbon particles and carbon powder, and it is preferable to maintain the melt in a reducing environment.

However, it is difficult to industrially prevent the oxidation of the above-mentioned alloying elements, and also the refractory material of the melting furnace or the above-mentioned carbon powder. The possibility of being caught in the ingot and becoming a non-metallic inclusion. In order to prevent the intrusion of such non-metallic inclusions, it is preferred to use a vertical continuous casting machine to cast the feed tank and the distributor to float the non-metallic inclusions.

(hot rolling step)

The ingot produced by the vertical continuous casting machine is cut to a specific length and then hot rolled.

In the final stage of hot rolling, it is preferable to set the rolling ratio per one pass to 20% or more and 40% or less, and to perform hot rolling at a hot rolling end temperature of 550 ° C or more and 650 ° C or less.

After hot rolling to a temperature of 200 ° C or less, it is preferable to rapidly cool at a cooling rate of 200 ° C / min or more. Thus, a copper alloy rolled sheet having an average crystal grain size of 50 μm or less and a Vickers hardness of 60 Hv or more and 120 Hv or less can be obtained.

(leveling processing step / cold rolling step and heat treatment step)

After the hot rolling and cooling described above, in order to improve the flatness of the rolled sheet, leveling processing or cold rolling processing may be performed.

In the case of leveling or cold rolling, in order to adjust the average crystal grain size and Vickers hardness, heat treatment is carried out at a temperature of 350 ° C to 550 ° C for 1 to 2 hours, and cooling is performed in the atmosphere. More ideal.

(Machining step)

The copper alloy rolled sheet obtained as described above is preferably ground and polished on the surface of the sputtering surface, and the surface roughness of the sputtering surface is preferably adjusted so that the maximum height Rz is 5 μm or less.

The copper alloy sputtering target of the present embodiment is produced by the above steps.

The copper alloy is sputter-plated on a sputter plate made of copper, mounted in a sputtering apparatus, and a copper alloy film is sputter-plated on the oppositely disposed substrate to form a film.

Here, the copper alloy film to be sputtered into a film has a composition equivalent to that of the above-described copper alloy sputtering target.

According to the copper alloy sputtering target of the present embodiment having the above-described configuration, since the maximum particle diameter of the non-metallic inclusions is limited to 10 μm or less, the non-metallic inclusions can be suppressed during the sputtering film formation. The charge is accumulated to cause abnormal discharge, and sputtering can be stably performed to form a film.

In addition, in the copper alloy sputtering target of the present embodiment, Ni is contained, or Ni and Al are in total of 5 mass% or more and 15 mass% or less (however, it contains Ni 0.5 mass% or more), and Mn 0.1 mass% or more and 5.0 mass% are contained. In the following, the content of Fe 0.5 mass% or more and 7.0 mass% or less is contained, and the remaining portion has a composition composed of Cu and unavoidable impurities. Therefore, the weather resistance is excellent, and discoloration of the formed copper alloy film can be suppressed.

In addition, since the total content of Ni, the content of Ni, and the content of Al is less than 15 mass%, the hot workability and the machinability are excellent, and the copper alloy sputtering target can be produced with good yield. Further In one step, since the content of Ni is set to 0.5 mass% or more, the hot rolling property can be improved, and the occurrence of cracking during hot rolling can be suppressed.

Further, in the case where Al is added as an alternative to Ni, the content of Ni can be lowered, and the manufacturing cost of the copper alloy sputtering target can be reduced.

Further, in the copper alloy sputtering target of the present embodiment, since Mn is contained in a range of 0.1 mass% or more and 5.0 mass% or less, the hot workability can be improved by the improvement of the fluidity at the time of casting. .

In addition, since Fe is contained in a range of 0.5 mass% or more and 7.0 mass% or less, the metal structure is sufficiently refined, and hot workability can be improved.

In this way, since the hot workability is sufficiently improved, the occurrence of cracking during hot rolling can be suppressed, and a large-sized sputtering target having an area of the sputtering surface of 100,000 mm ² or more can be produced with good yield.

In addition, in the copper alloy sputtering target of the present embodiment, since the average crystal grain size on the sputtering surface is 50 μm or less, even when the sputtering is performed, irregularities of the crystal grains are formed on the sputtering surface. The unevenness is also large, which can suppress the occurrence of abnormal discharge.

Further, in the copper alloy sputtering target of the present embodiment, since the Vickers hardness on the sputtering surface is 60 Hv or more, the crystal grain size can be made small, and the sputtering surface can be sputtered. Forming irregularities of the crystal grains can also suppress the occurrence of abnormal discharge.

In addition, since the Vickers hardness of the sputtered surface is set to 120 Hv or less, Therefore, the internal strain in the crystal grains is small, and the release of the sputtered particles becomes uniform, and the uniformity of the film thickness of the formed copper alloy film can be improved. Further, it is possible to suppress unevenness in sputtering rate due to internal strain, and it is possible to suppress formation of large irregularities on the sputtering surface during sputtering, and it is possible to suppress occurrence of abnormal discharge.

Further, in the copper alloy sputtering target of the present embodiment, since the surface roughness of the sputtering surface is set to 5 μm or less at the maximum height Rz, it is possible to suppress the concentration of the front end of the convex portion which is protruded from the sputtering surface after the start of use. An abnormal discharge is generated by electric charge, and sputtering can be stably performed to form a film.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and can be appropriately modified without departing from the scope of the invention.

For example, in the present embodiment, a large-sized sputtering target having an area of the sputtering surface of 100000 mm ² or more is described as a flat plate shape. However, the shape of the copper alloy sputtering target is not particularly limited and can be produced. It has a disk shape or a rectangular plate shape and can also be used as a cylindrical shape. Further, the area of the sputtering surface is not limited to the above range.

[Examples]

Hereinafter, the results of the evaluation test evaluated in relation to the effects of the copper alloy sputtering target of the present invention will be described.

As the melting raw material, oxygen-free copper having a purity of 99.99 mass% or more, low-carbon nickel having a purity of 99.9 mass% or more, electrolytic manganese having a purity of 99.9 mass% or more, electrolytic iron having a purity of 99.95 mass% or more, and pure aluminum having a purity of 99.9 mass% or more are prepared. , using a high frequency induction heating furnace in the atmosphere The composition was melted and the composition was adjusted in such a manner as to become the target composition shown in Table 1. In addition, the presence or absence of the carbon particles and the melt coating of the carbon powder at the time of melting are shown in Table 2.

The composition-adjusted melt was injected into a vertical continuous casting machine by a dispenser to produce an ingot having a rectangular cross section of 620 mm × 220 mm. The top and bottom of the ingot were cut and removed to obtain an ingot of 620 mm × 220 mm × 900 mm in length.

Next, this ingot was subjected to hot rolling to obtain a rolled plate of 1100 mm × 5500 mm × thickness of 20 mm. Further, the conditions for modifying the hot rolling are shown in Table 2.

Further, the rolled sheet after the hot rolling is cooled by spraying water. The cooling rate at this time is shown in Table 2. Further, in Example 11 of the present invention, after hot rolling, cooling was carried out without water cooling.

Further, in Examples 4 and 10 of the present invention, after cold rolling at the total rolling ratio shown in Table 2, the heat treatment was carried out at 500 ° C for 1 hour.

Next, from the obtained rolled plate, a target of 126 mm × 178 mm × 6 mm in thickness was cut out using a cutting machine, and the sputtered surface was modified by milling.

The obtained copper alloy sputtering target was welded to a copper base plate, and further polished on the sputtering surface. In the polishing process, the abrasive grains to be used are sequentially changed from the coarse mesh (#150) to the fine mesh (#800) to be polished to reduce the surface roughness, and then the dust adhering to the polishing is washed and removed.

Regarding the evaluation target obtained in such a manner, the maximum particle diameter, the average crystal grain size, the Vickers hardness, and the non-metallic inclusions are The surface roughness (maximum height Rz) of the sputtered surface, the number of abnormal discharges (the number of micro-arc discharges), the weather resistance of the film, and the uniformity of the film thickness were evaluated in the following manner. Further, the weather resistance of the laminated film of the copper alloy film laminated on the copper film made of pure copper and the composition of the formed copper alloy film were also evaluated.

(non-metallic inclusions)

A sample for observation of each tissue was cut out in a range of nine divisions in which the target sputtering surface was divided into three equal parts, and the sputtering surface was polished by EPMA (electron beam microanalyzer). Organizational observation. For each sample, the field of view of 10 places was observed at a magnification of 100 times, and the case where non-metallic inclusions were observed in the field of view was the largest non-metallic inclusion, and the length in the longest direction was measured. Since non-metallic inclusions are specified, qualitative analysis by EPMA is suitable, and non-metallic inclusions composed of oxygen and alloying elements are confirmed. The largest non-metallic inclusions among the nine samples were specified as the maximum particle size of the non-metallic inclusions. The evaluation results are shown in Table 3.

(average crystal grain size)

Four samples cut out from the corners of the target among the nine samples from which the non-metallic inclusions were observed were used for the measurement of the crystal grain size.

The polished surface of each sample was etched to the visible grain boundary by dilute nitric acid, and the average crystal grain size was measured by an optical microscope according to the cutting method prescribed in JIS H0501-1986, and the average crystal grain size of 4 samples was determined. Flat Mean. The evaluation results are shown in Table 3.

(Vickers hardness)

Four samples of the average crystal grain size were measured, and the Vickers hardness was measured in accordance with JIS Z2244-2009, and the average value of the four samples was determined. Still, the test force was set to 0.98N. The evaluation results are shown in Table 3.

(Surface roughness)

The surface roughness (maximum height Rz) of the sputtering surface of the evaluation target was measured using a probe type surface roughness meter (SURFCOM 130A manufactured by Tokyo Seimitsu Co., Ltd.) in accordance with JIS B0601-2001. The measurement conditions were an evaluation length of 4 mm, a cutoff value of 0.8 mm, a λ _{S of} 2.5 μm, and a measurement speed of 0.3 mm/sec. The average value was determined by dividing the target in the 126 mm direction by two, and measuring the maximum height Rz at three points in the 178 mm direction by three equal parts. The evaluation results are shown in Table 3.

(number of micro arc discharges)

The evaluation target was attached to the sputtering apparatus, and the number of micro-arc discharges generated in one hour after the start of use (initial use) and the number of micro-arc discharges generated within one hour after the start of use were counted (consumption) Rear). The number of micro-arc discharges is counted by detecting the drop in the discharge voltage by an arc counting function attached to the sputtering power source. Further, the sputtering conditions were carried out under the conditions of an ultimate vacuum of 5 × 10 ^-5 Pa, a gas pressure of 0.3 Pa of argon, and a sputtering power of 2000 W. The results of the number of micro-arc discharges after the initial use and target consumption are shown in Table 3.

(weather resistance of film)

The 50 mm × 50 mm × 0.7 mm alkali-free glass substrate was placed opposite to each other so that the distance between the target and the substrate was 60 mm, and the ultimate vacuum was 5 × 10 ^-5 Pa, air pressure: 0.3 Pa argon, sputtering power: DC 700 W Under the conditions of sputtering, a copper alloy film having a film thickness of 150 nm was formed on the substrate.

The film-formed copper alloy film was subjected to a constant temperature and humidity test under the conditions of a constant temperature and humidity of 60 ° C and a relative humidity of 90% for 250 hours, and then the surface of the copper alloy film was visually observed to recognize that the color change was set to " NG", it is not possible to confirm that the color change is set to "OK" and evaluate. The evaluation results are shown in Table 3.

(uniformity of film thickness)

A copper alloy film was formed on the glass substrate at a target film thickness of 500 nm under the same sputtering conditions as described above. The film thickness of the copper alloy film which had been formed was measured at positions of nine places which were equally arranged in a range of 3 × 3 in a plane of 50 mm × 50 mm. The film thickness is measured by previously applying a heat-resistant tape to the glass substrate at 9 places, tearing off the tape after film formation, and forming a step by the formed copper alloy film, and measuring the step by a step difference. The film thickness of the copper alloy film was set. Further, the uniformity of the film thickness was evaluated as (maximum film thickness - minimum film thickness) / average value of film thickness × 100. The evaluation results are shown in Table 3.

(Evaluation of laminated film)

A pure copper target was prepared, and an alkali-free glass substrate of 50 mm × 50 mm × 0.7 mm was disposed so as to have a distance between the target and the substrate of 60 mm, with an ultimate vacuum of 5 × 10 ^-5 Pa, a gas pressure of 0.3 Pa, and sputtering. Power: Sputtering was performed under conditions of 700 W DC, and a pure copper film having a film thickness of 150 nm was formed on the substrate.

Next, using a target for evaluation, a copper alloy film having a thickness of 30 nm was formed on the pure copper film under the same sputtering conditions (film formation conditions at the time of evaluation of weather resistance of the film) to obtain a laminated film.

The film-formed laminated film was subjected to a constant temperature and humidity test at a constant temperature and humidity of 60 ° C and a relative humidity of 90% for 250 hours, and the results of the laminated film were visually observed to confirm the film formation on the substrate. The copper alloy film having a film thickness of 150 nm has the same tendency.

(composition of copper alloy film)

A copper alloy film having a thickness of 1 μm was formed on the glass substrate under the same sputtering conditions as those described above (film formation conditions at the time of evaluation of weather resistance of the film).

This copper alloy film was used as a measurement sample, and component analysis was performed by the ICP-AES method. As a result, it was confirmed that the composition of the copper alloy sputtering target was substantially equal to the composition of the copper alloy film.

In Comparative Example 2 in which the content of Ni exceeded 15 mass%, Comparative Example 3 in which the content of Mn was less than 0.1 mass%, Comparative Example 5 in which the content of Fe was less than 0.5 mass%, and Comparative Example 6 in which the content of Fe exceeded 7.0 mass%, Comparative Example 8 in which the total of the content of Ni and the content of Al exceeds 15 mass%. Comparative Example 9 containing no Ni was confirmed to be cracked during hot rolling. Therefore, no other assessments are made regarding these systems.

Comparative Examples 1 and 7 in which the total content of Ni and the content of Al were less than 5 mass% were recognized as discoloration in the copper alloy film after the constant temperature and humidity test, and the weather resistance was insufficient.

In Comparative Example 4 in which the content of Mn exceeded 5.0 mass%, the maximum particle diameter of the non-metallic inclusions exceeded 10 μm, and the number of micro-arc discharges increased. It is presumed that a large amount of Mn oxide is produced.

Further, in Comparative Examples 10 and 11 in which the melt coating was not applied, the maximum particle diameter of the non-metallic inclusions exceeded 10 μm, and the number of micro-arc discharges increased.

On the other hand, in the range of the present invention, the maximum particle diameter of the non-metallic inclusions is 10 μm or less, and the copper alloy film excellent in weather resistance can be formed into a film, and micro-arc discharge can be suppressed. The number of times can be stably deposited by sputtering.

Further, in the inventive examples 11, 12, and 13 in which the average crystal grain size exceeded 50 μm, the number of micro-arc discharges after consumption increased. Therefore, it is preferable that the average crystal grain size is 50 μm or less.

Further, in the case of the invention of Example 14 in which the Vickers hardness exceeded 120 Hv, the number of micro-arc discharges increased, and the film thickness was scattered. Further, in the above-described inventive examples 11, 12, the Vickers hardness was less than 60 Hv. Therefore, it is preferable that the Vickers hardness is 60 Hv or more and 120 Hv or less.

In view of the above, it was confirmed that a copper alloy sputtering target capable of forming a copper alloy excellent in weather resistance can be provided according to an example of the present invention. The film can suppress the occurrence of abnormal discharge at the time of film formation, and is excellent in hot workability.

[Industrial availability]

By using the copper alloy sputtering target of the present invention, it is possible to form a high-quality copper alloy film with high precision and efficiency. As a result, in the manufacture of a flat panel display or a touch panel, the manufacturing process is more efficient, and the raw product is also higher in quality.

Claims (3)

A copper alloy sputtering target characterized by containing Ni, or Ni and Al in total of 5 mass% or more and 15 mass% or less (however, containing Ni 0.5 mass% or more), and containing Mn 0.1 mass% or more and 5.0 mass% or less, and containing Fe 0.5 mass% or more and 7.0 mass% or less, and the remainder has a composition composed of Cu and unavoidable impurities, and the maximum particle diameter of the non-metallic inclusions is 10 μm or less. The copper alloy sputtering target according to claim 1, wherein the average crystal grain size on the sputtering surface is 50 μm or less. The copper alloy sputtering target according to claim 1 or claim 2, wherein the Vickers hardness of the sputtering surface is in a range of 60 Hv or more and 120 Hv or less.