JP5740891B2 - Cu-Ga alloy sputtering target and method for producing Cu-Ga alloy sputtering target - Google Patents

Description

  The present invention relates to a Cu—Ga alloy sputtering target used for forming a light absorption layer of a CIGS (Cu—In—Ga—Se quaternary alloy) solar cell and a method for producing the Cu—Ga alloy sputtering target. .

  In recent years, photovoltaic power generation has attracted attention as one of clean energy. Although crystalline Si solar cells are mainly used, CIGS (Cu—In—Ga—Se quaternary alloy) solar cells with high conversion efficiency are attracting attention because of supply and cost problems. Yes.

  The CIGS solar cell has, as a basic structure, a Mo electrode layer serving as a back electrode formed on a soda lime glass substrate and a Cu—In—Ga—Se serving as a light absorption layer formed on the Mo electrode layer. A quaternary alloy film, a buffer layer made of ZnS, CdS, etc. formed on the light absorption layer made of this Cu-In-Ga-Se quaternary alloy film, and formed on this buffer layer A transparent electrode.

  As a method for forming a light absorption layer made of a Cu—In—Ga—Se quaternary alloy film, a vapor deposition method is known, but in order to obtain a uniform film with a wider area, a method of forming by a sputtering method. Has been proposed.

  As a sputtering method, for example, first, an In film is formed by sputtering using an In target, and a Cu—Ga alloy film is formed on the In film by sputtering using a Cu—Ga alloy sputtering target. There is a method of forming a Cu—In—Ga—Se quaternary alloy film by forming a film and heat-treating the obtained laminated film composed of the In film and the Cu—Ga alloy film in a Se atmosphere.

  Since the quality of the Cu—In—Ga—Se quaternary alloy film formed by this sputtering method largely depends on the quality of the Cu—Ga alloy sputtering target, it is necessary to use a high quality Cu—Ga alloy sputtering target. It is desired.

  As a method for producing a Cu—Ga alloy sputtering target, a melting method and a powder sintering method are known.

  For example, Patent Document 1 proposes a Cu—Ga alloy sputtering target produced by a melting method. The melting method has a problem that a Cu—Ga alloy having a composition for CIGS solar cells obtained by melting and casting is brittle and easily cracked.

  Patent Document 1 describes a problem that a Cu—Ga alloy sputtering target produced by a powder sintering method contains oxygen and abnormal discharge occurs. In addition, Patent Document 1 does not describe a clear upper limit for the oxygen content at which abnormal discharge is suppressed with respect to such a problem.

  The powder sintering method is promising as a method of manufacturing a sputtering target because it has a uniform composition although it has such problems. As a powder sintering method, for example, in Patent Document 2, a high Ga-containing Cu—Ga alloy powder and pure Cu or a low Ga-containing Cu—Ga alloy powder are blended to produce a sputtering target by hot pressing. Is described. Also in this patent document 2, it does not describe about the abnormal discharge by oxygen or about oxygen content by which abnormal discharge is suppressed.

JP 2000-73163 A JP 2008-138232 A

  In the powder sintering method, since the melting point of Ga is as low as 29.78 ° C., a sintered body cannot be obtained directly from Cu powder and Ga. For this reason, Cu-Ga alloy powder is used as a raw material as in Patent Document 2. The Cu—Ga alloy powder used as a raw material is generally produced by melting and alloying Cu and Ga once by using the fact that the Cu—Ga alloy is a brittle material. That is, in order to obtain Cu—Ga alloy powder, a process of melting Cu and Ga at a high temperature to form an alloy and a process of pulverizing such as pulverizing the Cu—Ga alloy ingot are required.

  Such a high-temperature process for dissolving Cu and Ga and a pulverization process by pulverization are processes that easily oxidize a Cu-Ga alloy. A Cu—Ga alloy sputtering target produced using an oxidized Cu—Ga alloy has a large amount of oxygen, and when a large amount of power is applied and sputtered, abnormal discharge occurs as described in Patent Document 1. .

  The Cu—Ga alloy sputtering target is sputtered by applying a large electric power from the viewpoint of increasing the deposition rate and improving the productivity. Abnormal discharge becomes apparent when the input power is increased. And when abnormal discharge arises, a defect is induced to a sputtered film, and the yield of a solar cell will fall.

  Therefore, the present invention has been proposed in view of such a conventional situation, and has a high quality in which abnormal discharge does not occur even when a film is formed by reducing the oxygen content and applying a large sputtering power. It aims at providing the manufacturing method of a Cu-Ga alloy sputtering target and this Cu-Ga alloy sputtering target.

The Cu—Ga alloy sputtering target according to the present invention that achieves the above-described object is characterized in that the oxygen content is 0.06 wt% to 0.2 wt% .

  Moreover, the manufacturing method of the Cu-Ga alloy sputtering target based on this invention which achieves the objective mentioned above mix | blends Cu powder and Ga by the ratio of 85: 15-55: 45 by mass ratio, and oxygen content is 0. The mixed powder of .2 wt% or less is alloyed in an atmosphere having an oxygen partial pressure of 20 Pa or less, and the obtained Cu—Ga alloy powder is sintered by a hot press method.

In the present invention, since the oxygen content contained in the Cu—Ga alloy sputtering target is as low as 0.06 wt% to 0.2 wt% , abnormal discharge occurs even when a large amount of power is applied to form a film by sputtering. Can be prevented.

  Below, the Cu-Ga alloy sputtering target to which this invention is applied and the manufacturing method of this Cu-Ga alloy sputtering target are demonstrated in detail. Note that the present invention is not limited to the following detailed description unless otherwise specified.

<Cu-Ga alloy sputtering target>
First, a Cu—Ga alloy sputtering target will be described. The Cu—Ga alloy sputtering target can be produced by a powder sintering method using Cu—Ga alloy powder as a raw material, and the oxygen content is 0.2 wt% or less. When the oxygen content exceeds 0.2 wt%, abnormal discharge is likely to occur during sputtering, and defects are generated in the generated film. Therefore, in the Cu—Ga alloy sputtering target, by setting the oxygen content to 0.2 wt% or less, the occurrence of abnormal discharge can be prevented even when the sputtering input power is increased, and defects in the film can be prevented.

  Here, the mechanism of the abnormal discharge is not clear, but when the oxygen content in the target is large, an electrically insulating structure is formed in the target, which is considered to be caused by this. This electrically insulating structure is expected to repeat small charges and discharges during sputtering, and it is considered that when the power supplied to the sputtering is increased, the charge is increased and abnormal discharge is caused. When the oxygen content is 0.2 wt% or less, the proportion of the electrically insulating structure is sufficiently small, so that charging is small and abnormal discharge is not caused.

<Method for producing Cu-Ga alloy sputtering target>
Next, the manufacturing method of a Cu-Ga alloy sputtering target is demonstrated. A method for producing a Cu—Ga alloy sputtering target comprises producing Cu—Ga alloy powder from Cu powder and Ga in a low oxygen partial pressure atmosphere, and sintering the obtained Cu—Ga alloy powder to obtain Cu—Ga alloy sputtering. Manufacture the target.

<1. Method for producing Cu-Ga alloy powder>
First, the manufacturing method of Cu-Ga alloy powder is demonstrated.

(material)
Cu powder and Ga are used as raw materials for the Cu—Ga alloy powder. The purity of the Cu powder and Ga is appropriately selected so as not to affect the characteristics of the CIGS light absorption layer formed from the Cu—Ga alloy sputtering target.

  As the Cu powder, for example, electrolytic Cu powder or atomized Cu powder produced by an electrolytic method or an atomizing method can be used. The electrolytic Cu powder is produced by depositing spongy or dendritic Cu on the cathode by electrolysis in an electrolytic solution such as a copper sulfate solution. As for the atomized Cu powder, spherical or irregular shaped Cu powder is produced by a gas atomization method, a water atomization method, a centrifugal atomization method, a melt extraction method, or the like. In addition, you may use what was manufactured by Cu methods other than these methods.

  The average particle size of the Cu powder is preferably 1 to 300 μm. When the average particle size of the Cu powder is less than 1 μm, special handling for preventing the scattering of the Cu powder is required, the bulk capacity of the Cu powder is increased, the size of the alloy powder manufacturing apparatus is increased, and the cost is increased. A device is required. Further, when the average particle size of the Cu powder exceeds 300 μm, the surface area (BET) of the Cu powder that must be coated with Ga decreases, and the amount of Ga required for the coating also decreases, resulting in an excess. Furthermore, since the liquid phase of unreacted Ga remains, Ga cannot be used effectively. Therefore, by setting the average particle size of Cu powder to 1 to 300 μm, it is not necessary to take measures to prevent scattering of Cu powder, the enlargement of the alloy powder production apparatus can be prevented, and the liquid phase of unreacted Ga can be reduced. It can be reduced, and Ga can be used effectively.

  The average particle size of the Cu powder is obtained by measuring the particle size distribution of the Cu powder by a laser diffraction method, integrating the abundance ratio (volume basis) from the small diameter side, and integrating the abundance ratio over the entire particle diameter. The particle size (D50) is half of the value.

  Ga is a metal having a low melting point (melting point: 29.78 ° C.) and is easily melted by heating. The molten Ga is coated with Cu powder to form a binary alloy. Although there is no restriction | limiting in the shape of Ga, when it is a small piece, weighing is easy. The small piece can be obtained by melting and casting Ga in the vicinity of room temperature and crushing the casting.

(Combination)
Cu powder and Ga are mix | blended in the ratio of 85: 15-55: 45 by mass ratio. When the amount of Ga is 15% by mass or more, uniform coating with Ga becomes possible, and a uniform alloy structure can be obtained when the obtained powder is sintered. Moreover, when the amount of Ga is 45% by mass or less, Cu powders can be prevented from being combined and formed into a lump by a large amount of Ga existing between Cu powders, and the yield of the alloy powder is improved. be able to.

  Moreover, it is preferable that content of Ga is 25-41 mass%. When Ga is 25% by mass or more, Cu powder can be uniformly coated in a short time, and when Ga is 41% by mass or less, Ga coated in a short time can be alloyed. it can. Therefore, a uniform alloy powder can be produced in a short time by setting the Ga content to 25 mass% or more and 41 mass% or less.

  In the mixed powder in which Cu powder and Ga are blended at such a mass ratio, the oxygen content in the Cu-Ga alloy sputtering target is reduced by setting the oxygen content to 0.2 wt% or less. Can do. Here, the oxygen content in the mixed powder is determined from the oxygen content in the copper powder × the mass% of the copper powder + the oxygen content in Ga × the mass% of Ga. The oxygen content in Cu powder and Ga is measured with a zirconia oxygen concentration meter or the like.

(Alloying)
The mixed powder in which Cu powder and Ga are blended at the above-described mass ratio is stirred and alloyed while heating in a low oxygen partial pressure atmosphere. The low oxygen partial pressure atmosphere is, for example, an oxygen partial pressure of 20 Pa or less, an inert gas atmosphere such as an argon atmosphere or a nitrogen atmosphere, or a vacuum atmosphere having a degree of vacuum of 100 Pa or less obtained by evacuating the air. When the oxygen partial pressure in the low oxygen partial pressure atmosphere is larger than 20 Pa, the Cu—Ga alloy powder is oxidized.

  As an alloying method, for example, using a glove box, after evacuating until the oxygen partial pressure in the glove box is 20 Pa or less, an inert gas such as argon is introduced, and an inert atmosphere is obtained. The mixed powder of Cu powder and Ga is heated to a temperature of 30 to 400 ° C. while stirring to alloy Cu powder and Ga.

  As another alloying method, for example, while the inside of the stirring mixer is evacuated or evacuated, the oxygen partial pressure is maintained at 20 Pa or less and heated to a temperature of 30 to 400 ° C. while stirring to obtain Cu powder And Ga are alloyed. As the agitation mixer, a mixing device in which an agitator such as a stirring blade or a stirring blade moves in the container can be used. Moreover, you may use rotating container type mixing apparatuses, such as a cylinder, a double cone, and a twin shell. Also, mixing may be strengthened by throwing balls into the container. The container material is selected from the viewpoints of heat resistance against heating and suppression of adhesion of Ga and Cu—Ga alloys. Examples of the container include glass containers such as borosilicate glass and quartz glass, ceramic containers such as alumina and zirconia, Teflon resin containers, Teflon-coated containers, and enamel containers.

  By alloying by such a method, a Cu—Ga binary alloy powder in which Ga is dispersed on the surface or inside of the Cu powder can be produced. In such an alloying method, since the oxygen partial pressure is 20 Pa or less and alloying is performed in an inert gas atmosphere such as argon gas or nitrogen gas, or an oxygen partial pressure of 20 Pa or less, the oxygen content is 0. An increase in the oxygen content of the Cu—Ga alloy powder produced from the mixed powder of 2 wt% or less can be suppressed.

  The Cu—Ga alloy powder is considered to be formed through the following process. Ga, which has become liquid beyond the melting point, is uniformly dispersed between Cu powders while becoming small droplets by the shearing motion of mixing. The dispersed Ga droplets adhere to the periphery of the Cu powder, and when the Cu powder and Ga droplets come into contact with each other, the Ga powder begins to diffuse into the Cu powder, and the Ga concentration increases while alloying while forming a Cu-Ga intermetallic compound. The reaction proceeds. At this time, the surface of the Cu—Ga alloy powder is a Cu—Ga intermetallic compound layer having a high Ga concentration, and the central portion is a Cu phase in which pure Cu or Ga is dissolved.

  This mixing of Cu powder and Ga is effective for the progress of a uniform alloying reaction. Moreover, it is considered that the shearing motion of mixing also suppresses the formation of a lump due to the adhesion between the powders. If a lump is generated, voids are generated in the sintered body in a sintering process such as hot pressing, and the density becomes non-uniform.

  The Cu—Ga alloy powder produced in this way is not only excellent in strength and formability, but also because the production temperature is low, the equipment used for production becomes simple, so the alloy powder can be produced at low cost. It has the advantage of being able to.

  In the manufacturing method of the above Cu-Ga alloy powder, Cu powder and Ga are mix | blended in the ratio of mass ratio 85: 15-55: 45, and it heats in the range of 30 to 400 degreeC, and is alloyed. As a result, Cu—Ga alloy powder having excellent formability can be obtained. In addition, since the Cu-Ga alloy powder manufacturing method does not require the step of pulverizing the Cu-Ga alloy ingot as in the prior art, there is no oxidation of the Cu-Ga alloy powder in the pulverization step, and the Cu-Ga alloy powder is not oxidized. Powder can be easily manufactured.

<2. Manufacturing method of Cu-Ga alloy sputtering target>
Next, the manufacturing method of the Cu-Ga alloy sputtering target using the Cu-Ga alloy powder mentioned above is demonstrated.

(Sintering)
First, the Cu—Ga alloy powder is pressed and sintered. Sintering uses a hot press method in which a Cu—Ga alloy powder is pressed and heated by a hot press apparatus in a vacuum or in an inert gas atmosphere. According to the hot press method, a high-density sintered body can be obtained at low cost. Sintering is performed by applying a hot press pressure of, for example, about 5 MPa or more and 30 MPa or less to the Cu-Ga alloy powder with an upper punch and a lower punch of a hot press apparatus, and pressurizing and sintering at a heating temperature of 400 ° C to 900 ° C. Do it. The sintering is preferably performed in an inert gas atmosphere having an oxygen partial pressure of 0.001 to 0.01 Pa.

  The obtained sintered body has an oxygen content of Cu-Ga alloy powder of 0.2 wt% or less, and is sintered in a vacuum or in an inert gas atmosphere, so the oxygen content is 0.2 wt% or less. The oxygen content is very low.

(Finishing)
A finishing process is performed after sintering. For finishing, the surface of the sintered body of the Cu—Ga alloy is flattened by grinding and bonded to a Cu backing plate. Thereby, a Cu—Ga alloy sputtering target having an oxygen content of 0.2 wt% or less can be obtained.

  In addition, you may make it heat-process to Cu-Ga alloy powder before sintering. The heat treatment is performed with no load on the Cu-Ga alloy powder in a vacuum or in an inert atmosphere, or 0.1 MPa or less (added by the weight of the upper punch when the upper punch is installed in a hot press apparatus) By heating to 400 ° C. to 900 ° C. under a pressure of The heat treatment time is preferably 1 hour or more and 8 hours or less. By performing heat treatment on the Cu-Ga alloy powder before sintering, the homogenization reaction between the Cu powder and Ga progressed, Ga diffused in the center of Cu, and the appearance of the Ga liquid phase was suppressed. A high-quality sintered body can be manufactured.

  As described above, in the method for producing a Cu—Ga alloy sputtering target, the oxygen content of the mixed powder in which Cu powder and Ga are blended at a ratio of 85:15 to 55:45 is 0.2 wt% or less, The mixed powder is stirred and alloyed while being heated in a low oxygen partial pressure atmosphere having an oxygen partial pressure of 20 Pa or less. By sintering the obtained Cu—Ga alloy powder, The oxygen content can be 0.2 wt% or less.

  The obtained Cu—Ga alloy sputtering target has an oxygen content of 0.2 wt% or less and a low oxygen content, so even when a large amount of power is applied to form a film by sputtering, abnormal discharge does not occur. Further, a sputtered film having no defects can be formed, and the production efficiency can be increased. Therefore, for example, when a light absorption layer of a solar cell is formed using this Cu—Ga alloy sputtering target, a light absorption layer free from defects and the like can be formed, and the yield of the solar cell can be increased.

  Hereinafter, specific examples to which the present invention is applied will be described, but the present invention is not limited to these examples.

Example 1
In Example 1, first, 68 g of electrolytic copper powder (average particle size 97 μm) having an oxygen content of 0.04 wt% and 32 g of Ga having an oxygen content of 0.01 wt% or less were charged into a glass beaker. The oxygen content of the mixed powder of electrolytic copper powder and Ga was 0.03 wt%. The oxygen content of the mixed powder was determined from the oxygen content in the copper powder × the mass% of the copper powder + the oxygen content in Ga × the mass% of Ga. Next, this beaker, a mantle heater, and a stirrer were set in a glove box, and after evacuating the glove box, Ar gas was introduced. The oxygen concentration in the glove box was 0.1 ppm or less, that is, the oxygen partial pressure was 0.01 Pa or less as a result of measurement with a zirconia oxygen concentration meter (type ECOAZ TB-IIV, manufactured by Daiichi Thermal Laboratory Co., Ltd.). In this state, Cu powder and Ga were stirred while heating the inside of the beaker to 300 ° C. to prepare Cu—Ga alloy powder.

Next, this Cu—Ga alloy powder was put into a hot press and evacuated to 5 × 10 ⁻³ Pa. Since the oxygen ratio in the air is 21%, the oxygen partial pressure after evacuation is 0.001 Pa. Here, at the start of the hot press, the atmosphere pressure is 5 × 10 ⁻³ Pa by evacuating, but a gas is generated by the subsequent hot press operation. Because of the pressure, the oxygen partial pressure during hot pressing was 0.001 to 0.01. In this atmosphere, hot pressing was performed under the sintering conditions of 700 ° C. and 25 MPa to prepare a Cu—Ga alloy sputtering target having a diameter of 60 mm and a thickness of 3 mm.

  And as a result of sampling a part of Cu-Ga alloy sputtering target and performing oxygen analysis, oxygen content was 0.03 wt%. A Cu backing plate was joined to this target and attached to a sputtering apparatus (manufactured by ULVAC), and abnormal discharge was evaluated by sequentially applying DC 100 W and 200 W direct currents at an Ar gas pressure of 0.7 Pa. In Example 1, no abnormal discharge was observed at any input power.

(Example 2)
In Example 2, Cu—Ga was used in the same manner as in Example 1 except that atomized copper powder (average particle size 1 μm) having an oxygen content of 0.2 wt% and Ga having an oxygen content of 0.2 wt% were used. An alloy sputtering target was prepared. And as a result of sampling a part of Cu-Ga alloy sputtering target and analyzing oxygen, oxygen content was 0.2 wt%. About this Cu-Ga alloy sputtering target, it carried out similarly to Example 1, and evaluated abnormal discharge. As a result, no abnormal discharge was observed at any input power.

(Example 3)
In Example 3, a Cu—Ga alloy sputtering target was prepared in the same manner as in Example 1 except that the oxygen concentration in the glove box was 20 ppm, that is, the oxygen partial pressure was 2 Pa when the Cu—Ga alloy powder was produced. did. And as a result of sampling a part of Cu-Ga alloy sputtering target and analyzing oxygen, oxygen content was 0.2 wt%. About this Cu-Ga alloy sputtering target, it carried out similarly to Example 1, and evaluated abnormal discharge. As a result, no abnormal discharge was observed at any input power.

Example 4
In Example 4, first, 680 g of electrolytic copper powder having an oxygen content of 0.04 wt% (average particle size 97 μm) and 320 g of Ga having an oxygen content of 0.01 wt% or less were charged into a stirring mixer (manufactured by Shinagawa Kogyo Co., Ltd.). . And stirring was started at the heating temperature of 250 degreeC from the time of reaching vacuum degree 10Pa (oxygen partial pressure 2Pa), evacuating the inside of a stirring mixer, and produced Cu-Ga alloy powder. During the alloying, the inside of the stirring mixer is continuously evacuated, so that the inside of the stirring mixer is 10 Pa or less and the oxygen partial pressure is 2 Pa or less.

Next, this Cu—Ga alloy powder was put into a hot press and evacuated to 5 × 10 ⁻³ Pa. That is, the oxygen partial pressure is 0.001 Pa. In this state, hot pressing was performed under conditions of 700 ° C. and 25 MPa to prepare a Cu—Ga alloy sputtering target having a diameter of 60 mm and a thickness of 3 mm.

  And as a result of sampling a part of Cu-Ga alloy sputtering target and performing oxygen analysis, oxygen content was 0.03 wt%. About this Cu-Ga alloy sputtering target, it carried out similarly to Example 1, and evaluated abnormal discharge. As a result, no abnormal discharge was observed at any input power.

(Example 5)
In Example 5, Cu—Ga alloy powder was prepared in the same manner as in Example 1 except that the blending weights of copper powder and Ga were 85 g and 15 g, respectively. This Cu—Ga alloy powder was put into a hot press, evacuated to 5 × 10 ⁻³ Pa (oxygen partial pressure 0.001 Pa), and then Ar gas was introduced. A Cu—Ga alloy sputtering target having a diameter of 60 mm and a thickness of 3 mm was manufactured by hot pressing under conditions of 800 ° C. and 25 MPa with an Ar gas flow rate of 0.4 L / min.

  As a result of sampling a part of the Cu—Ga alloy sputtering target and analyzing the oxygen, the oxygen content was 0.03 wt%. About this Cu-Ga alloy sputtering target, it carried out similarly to Example 1, and evaluated abnormal discharge. As a result, no abnormal discharge was observed at any input power.

(Example 6)
In Example 6, a Cu—Ga alloy sputtering target was produced in the same manner as in Example 5 except that the blending weights of copper powder and Ga were 55 g and 45 g, respectively, and the hot press temperature was 400 ° C. And as a result of sampling a part of Cu-Ga alloy sputtering target and performing oxygen analysis, oxygen content was 0.03 wt%. About this Cu-Ga alloy sputtering target, it carried out similarly to Example 1, and evaluated abnormal discharge. As a result, no abnormal discharge was observed at any input power.

(Example 7)
In Example 7, a Cu—Ga alloy sputtering target was produced in the same manner as in Example 4 except that the degree of vacuum was 100 Pa (oxygen partial pressure 20 Pa). The degree of vacuum at the time of alloying was 100 Pa or less (oxygen partial pressure of 20 Pa or less). And as a result of sampling a part of Cu-Ga alloy sputtering target and analyzing oxygen, oxygen content was 0.15 wt%. About this Cu-Ga alloy sputtering target, it carried out similarly to Example 1, and evaluated abnormal discharge. As a result, no abnormal discharge was observed at any input power.

(Example 8)
In Example 8, a Cu—Ga alloy sputtering target was produced in the same manner as in Example 4 except that the degree of vacuum was 50 Pa (oxygen partial pressure 10 Pa). The degree of vacuum during alloying was 50 Pa or less (oxygen partial pressure of 10 Pa or less). As a result of sampling a part of the Cu—Ga alloy sputtering target and analyzing the oxygen, the oxygen content was 0.06 wt%. About this Cu-Ga alloy sputtering target, it carried out similarly to Example 1, and evaluated abnormal discharge. As a result, no abnormal discharge was observed at any input power.

(Comparative Example 1)
In Comparative Example 1, a Cu—Ga alloy sputtering target was produced in the same manner as in Example 1 except that the oxygen concentration in the glove box was 300 ppm, that is, the oxygen partial pressure was 30 Pa. As a result of sampling a part of the Cu—Ga alloy sputtering target and analyzing the oxygen, the oxygen content was 0.3 wt%. About this Cu-Ga alloy sputtering target, it carried out similarly to Example 1, and evaluated abnormal discharge. As a result, abnormal discharge did not occur in DC100W, but abnormal discharge occurred in DC200W.

(Comparative Example 2)
In Comparative Example 2, a Cu—Ga alloy sputtering target was performed in the same manner as in Example 1 except that atomized copper powder (average grain 150 μm) having an oxygen content of 0.4 wt% and Ga having an oxygen content of 0.2 wt% were used. Was made. As a result of sampling a part of the Cu—Ga alloy sputtering target and analyzing the oxygen, the oxygen content was 0.3 wt%. About this Cu-Ga alloy sputtering target, it carried out similarly to Example 1, and evaluated abnormal discharge. As a result, abnormal discharge did not occur in DC100W, but abnormal discharge occurred in DC200W.

  It shows in Table 1 about the manufacturing conditions of the Cu-Ga alloy sputtering target about the above Examples 1- Example 8, Comparative Example 1, and Comparative Example 2, and the presence or absence of abnormal discharge.

  From the results shown in Table 1, in Examples 1 to 8 in which the oxygen content in the Cu—Ga alloy sputtering target is 0.2 wt% or less, no abnormal discharge occurred even when the input power was DC 200 W. . Therefore, the Cu—Ga alloy sputtering target having an oxygen content of 0.2 wt% or less as in Examples 1 to 8 can form a defect-free film even when the film formation rate is increased, and the productivity is improved. Can be improved.

  On the other hand, in Comparative Example 1 and Comparative Example 2, when the input power is set to DC 200 W, abnormal discharge occurs. Therefore, defects due to abnormal discharge occur, and the film cannot be formed by increasing the film formation rate as in the example. .

  Therefore, even if the film formation rate is increased, a film having no defect can be formed, and the productivity can be improved because the oxygen content is 0.2 wt% as in Examples 1 to 8. % Cu—Ga alloy sputtering target.

Claims (2)

A Cu—Ga alloy sputtering target characterized by having an oxygen content of 0.06 wt% to 0.2 wt% .   Cu powder and Ga are blended in a mass ratio of 85:15 to 55:45, and a mixed powder having an oxygen content of 0.2 wt% or less is alloyed in an atmosphere having an oxygen partial pressure of 20 Pa or less. A method for producing a Cu-Ga alloy sputtering target, comprising sintering the obtained Cu-Ga alloy powder.