JP2014185384A - Cu-Ga SPUTTERING TARGET AND MANUFACTURING METHOD OF THE SAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Cu-Ga sputtering target of which strength with respect to cutting parallel to a target plane sputtered is secured even if Ga content is increased, and which can effectively suppress generation of splash, and a manufacturing method of the target.SOLUTION: A Cu-Ga sputtering target is provided, which has a Cu single area and a Ga containing area which is adjacent to the Cu single area, and contains at least Cu and Ga. Ga content to a total weight of the Cu single area and the Ga containing area is 20-65 mass%. An area ratio of the Cu single target on an arbitrary plane parallel to a target plane sputtered is 8% or more. Ga concentration gradient in a reaction phase formed between the Ga containing area and the Cu single area is 3.3 mass%/μm or less.

Description

  The present invention relates to a Cu-Ga sputtering target suitable for manufacturing CIGS solar cells and a method for manufacturing the same.

Recently, as a method of manufacturing a CIGS (Cu (In, Ga) Se ₂ ) solar cell, there is a selenization treatment method in which a precursor of CuGaIn is formed and then this precursor is Se-treated to produce a CIGS alloy. It is used as mass production technology. Examples of a method for forming a precursor of CuGaIn include a method of vapor-depositing Cu, Ga and In simultaneously, and a method of performing sputtering using an In target after performing sputtering using a Cu-Ga target. It is done.

  About a CIGS type solar cell, it is known that the efficiency of a solar cell will rise, if Ga content rate increases, as described in nonpatent literature 1. On the other hand, the Cu—Ga alloy becomes brittle and easily cracked as the Ga content increases. This crack is likely to appear when cutting (slicing) parallel to the surface of the target to be sputtered. Therefore, various studies have been conducted on Cu—Ga sputtering targets that contain Ga at a high concentration and are difficult to break. For example, Patent Document 1 describes that after a Cu-Ga melt containing Ga at a high concentration is prepared, an ingot is obtained by strictly controlling the cooling rate. Patent Document 2 discloses that a high Ga content Cu—Ga binary alloy grain is converted to a grain boundary phase of a low Ga content Cu—Ga binary alloy by performing hot pressing of two kinds of powders having a specific composition. Describes a method for producing a hot-pressed body having a structure surrounded by.

  However, since complicated temperature control is required to execute the method described in Patent Document 1, the method described in Patent Document 1 is not suitable for industrial mass production. In addition, with the method described in Patent Document 2, there is a possibility that cracking during cutting may be suppressed, but it is difficult to obtain a strength sufficient to withstand cutting (slicing) for obtaining a sputtering target from a hot press body. It is. Furthermore, when sputtering is performed using a target manufactured by the method described in Patent Document 2, splash associated with abnormal discharge may occur frequently.

JP 2000-073163 A JP 2008-138232 A JP 2011-241452 A JP 2012-017481 A JP 2012-072466 A

The latest technology of compound thin film solar cells (Takahiro Wada, 2007, CMC Publishing)

  The present invention provides a Cu-Ga sputtering target and a method for producing the same that can ensure the strength against cutting parallel to the target surface to be sputtered even when the Ga content is increased, and can effectively suppress the occurrence of splash. The purpose is to provide.

The present invention is as follows.
(1) Cu simple substance region;
A Ga-containing region adjacent to the Cu single region and containing at least Cu and Ga;
Have
Ga content rate with respect to the total mass of the Cu simple substance region and the Ga-containing region is 20 mass% to 65 mass%,
In any cross section parallel to the target surface to be sputtered, the area ratio of the Cu single region is 8% or more,
A Cu—Ga sputtering target, wherein a Ga concentration gradient in a reaction phase formed between the Ga-containing region and the Cu simple region is 3.3 mass% / μm or less.
(2) Furthermore, the area | region where the area ratio of the said Cu single-piece | unit area | region per 1 * 1mm in the arbitrary cross sections parallel to the target surface sputter | sputtered exists in the space | interval within a radius of at least 700 micrometers at least. The Cu—Ga sputtering target according to (1).
(3) A CuGa alloy γ phase is formed in the Ga-containing region, and the reaction phase is a phase formed between the γ phase and the Cu single region (1). ) Or Cu-Ga sputtering target according to (2).
(4) A step of obtaining a molded body having a porosity of 27.5% by volume to 86% by stacking a plurality of meshes made of Cu;
Impregnating Ga into voids of the mesh in the molded body;
Forming a CuGa alloy region by reacting the impregnated Ga and the mesh by holding at 350 ° C. to 750 ° C. in vacuum for 0.5 to 5 hours;
A method for producing a Cu-Ga sputtering target, comprising:
(5) A step of obtaining a molded body having a porosity of 27.5% by volume to 73% by stacking a plurality of Cu meshes and Cu plates;
Impregnating Ga into voids of the mesh in the molded body;
Forming a CuGa alloy region by reacting the impregnated Ga and the mesh by holding at 350 ° C. to 750 ° C. in vacuum for 0.5 to 5 hours;
A method for producing a Cu-Ga sputtering target, comprising:
(6) a step of pressing a spring-like wire to obtain a molded body having a porosity of 27.5% by volume to 73% by volume;
Impregnating Ga into voids of the mesh in the molded body;
Forming a CuGa alloy region by reacting the impregnated Ga and the mesh by holding at 350 ° C. to 750 ° C. in vacuum for 0.5 to 5 hours;
A method for producing a Cu-Ga sputtering target, comprising:
(7) A step of obtaining a molded body in which the Cu plates are arranged at a predetermined interval and the volume ratio of the gap portion between the Cu plates is 27.5% by volume to 73% by volume;
Impregnating Ga into the gaps between the Cu plates in the molded body;
Forming a CuGa alloy region by reacting the impregnated Ga and the Cu plate by holding at 350 ° C. to 750 ° C. in vacuum for 0.5 to 5 hours;
A method for producing a Cu-Ga sputtering target, comprising:
(8) In the step of forming the CuGa alloy region, Cu is held at 500 ° C. to 600 ° C. for 1 hour to 3 hours in a vacuum, Cu according to any one of (4) to (7) -Manufacturing method of Ga sputtering target.

  According to the present invention, even when the Ga content is increased, the strength against cutting parallel to the target surface to be sputtered can be sufficiently ensured, and further, the occurrence of splash can be effectively suppressed.

It is a figure for demonstrating the conditions where the area | region where the area ratio of the Cu single-piece | unit area | region per 1 * 1mm exists 8% or more mutually exists at the space | interval within the radius of 700 micrometers at least. It is a figure which shows an example of the structure of Cu mesh. It is a figure which shows an example of the molded object obtained by accumulating Cu mesh. It is a figure which shows the state in which Ga chip | tip was mounted on the molded object. It is a figure for demonstrating a mode that Ga and Cu are alloying. It is a binary system phase diagram of a Cu-Ga alloy. It is a figure which shows an example of Ga containing area | region. It is a figure which shows an example of the molded object obtained by arranging Cu mesh and Cu board alternately. It is a figure which shows an example of the state which disperse | distributed spring-like Cu wire.

  Of the sputtering target, the only part contributing to film formation is the erosion part. When the sputtering target is made of a composite material, the amount of each material sputtered is determined by the area ratio of the erosion portion of each material, and the ratio of components in the formed sputtered film is determined.

  Therefore, when a Cu-Ga sputtered film having a high Ga content is to be formed, the entire erosion part of the Cu-Ga sputtering target does not need to be a region having a high Ga content uniformly, and the erosion part. It is only necessary that the Ga-containing portion is large in the total area ratio. That is, a region where Ga is not present and a region where Cu is not present may be mixed in the Cu—Ga sputtering target.

  Therefore, the inventors of the present application paid attention to this point and conducted intensive studies. As a result, if the structure of the Cu—Ga sputtering target is made by dispersing a CuGa alloy having Ga in a Cu simple substance region (Cu aggregate), high strength is secured in the Cu simple substance region and good workability is achieved. It was found that a Cu—Ga sputtered film having a high Ga content can be formed.

  However, when the Cu simple substance region and the high Ga content CuGa alloy region are in contact with each other, due to the difference in the amount sputtered at the interface between the Cu simple substance region and the high Ga content CuGa alloy region as the sputtering proceeds. A large step occurs. When a portion having a large step exists in the sputtering target, charge concentration occurs using this portion as a protrusion, abnormal discharge occurs, and splash occurs. When the Cu simple substance region and the high Ga content CuGa alloy region are in contact with each other, such a splash problem may occur.

  Therefore, the inventors of the present application paid attention to this point and further studied diligently. As a result, if the low Ga-containing CuGa alloy region is interposed between the single Cu region and the high Ga-containing CuGa alloy region, the low Ga-containing CuGa alloy is sputtered between Cu and the high Ga-containing CuGa alloy. Therefore, it has been found that even if the sputtering progresses, a large step is hardly generated. Furthermore, when an alloy reaction phase is formed between the Cu simple substance region and the low Ga-containing CuGa alloy region, the change in the Ga content changes in a slope, and thereby the easiness of sputtering changes in a slope. It is possible to suppress the occurrence of abnormal discharge.

  Here, when a low Ga-containing CuGa alloy is interposed between the Cu simple substance region and the high Ga-containing CuGa alloy, the Cu simple substance region has a role of ensuring high strength and therefore remains to some extent. is necessary. As a result of diligent study, the present inventor has found that when the area ratio of the Cu single region is 8% or more in an arbitrary cross section parallel to the sputtering target surface of the sputtering target, the cutting is performed parallel to the sputtering surface. The knowledge which can ensure high intensity | strength when performing (slice) was acquired.

  The reason why the area ratio of the Cu simple substance region is 8% or more is that if the area ratio is less than 8%, the effect of improving brittleness due to the Cu simple substance region becomes too small, and there is a possibility that cracking may occur during processing. Note that the upper limit of the area ratio of the Cu single region is not particularly defined, but is calculated based on the Ga content and the ratio of the CuGa alloy. In addition, Preferably, the area ratio of Cu simple substance area | region is 10% or more.

  About Ga content rate, it is set as 20 mass%-65 mass% with respect to Cu total area | region and the total mass of a CuGa alloy. If the Ga content is less than 20% by mass, the efficiency of the intended solar cell cannot be obtained. Further, when the Ga content exceeds 65% by mass, the ratio of the Cu single region for ensuring high strength when performing cutting (slicing) parallel to the surface to be sputtered is too small, and thus the intended strength is obtained. In addition, the efficiency as a solar cell is reduced. In addition to Cu and Ga, a small amount of inevitable impurities such as mold components and atmospheric oxygen are included.

  Moreover, in order to suppress the occurrence of splash, the mass concentration gradient of Ga in the alloy reaction phase formed between the CuGa alloy and the Cu simple substance region is 3.3 mass so that a large step is less likely to occur even when the sputtering proceeds. % / Μm or less. When the Ga concentration gradient exceeds 3.3% by mass / μm, unevenness caused by sputtering becomes steep, and splash is likely to occur at the protrusions.

  Moreover, in order to ensure higher strength, it is preferable that the Cu simple substance region does not concentrate locally and a certain degree of dispersibility is ensured. Specifically, it is preferable that regions where the area ratio of the Cu single region per 1 × 1 mm in an arbitrary cross section parallel to the target surface to be sputtered is 8% or more are present at least within a radius of 700 μm. .

  FIG. 1 is a diagram for explaining the above conditions. As shown in FIG. 1, when the radius of the circle 13 is defined as 700 μm, the distance between the center points of the rectangles 11 and 12 of 1 × 1 mm is set. If the distance between the center points exceeds 700 μm, the proportion of the Cu—Ga alloy phase that is brittle than the Cu single region is higher in the meantime. The radius is preferably within 500 μm, and more preferably within a radius of 350 μm.

  Next, the manufacturing method of the Cu-Ga sputtering target which concerns on this invention is demonstrated.

(First embodiment)
In the present embodiment, a method of manufacturing a sputtering target using a Cu mesh will be described.
First, a Cu mesh 20 as shown in FIG. 2 is prepared. The shape of the portion where the Cu wires intersect in the Cu mesh may be a shape in which the wires in the vertical direction and the horizontal direction are connected, or may be a shape (plain weave) in which the wires in the vertical direction and the horizontal direction intersect by a step. The diameter of the Cu wire and the size of the gap are made different depending on the target Ga content. For example, the Ga content decreases as the diameter of the Cu wire increases, and the Ga content increases as the void size increases. Thus, the diameter of a Cu wire and the magnitude | size of a space | gap are determined with the target Ga content rate. In order to set the Ga content to 20 mass% to 65 mass% with respect to the total mass of the Cu simple substance region and the CuGa alloy, the porosity becomes 27.5 volume% to 73 volume% at the stage where the molded body is obtained. Thus, it is preferable to adjust the diameter of the Cu wire and the size of the gap.

  Then, the prepared Cu mesh 20 is cut into a predetermined size, and a predetermined number of pieces are arranged in a quartz crucible or the like to obtain a molded body 30 as shown in FIG. And as shown in FIG. 4, Ga chip | tip 40 is put on the molded object 30, and Ga is impregnated by Cu by performing heat processing. The impregnation with Ga is performed, for example, in a vacuum or in an inert atmosphere such as Ar. When performed in a vacuum, gas is easily released from the voids of the molded body 20, and Ga is easily impregnated therein.

  As a result of such impregnation, Ga is present in the gap 50 as shown in FIG. When arranging the Cu meshes, they may be arranged so that the positions of the gaps coincide with each other, or the gaps may be arranged irregularly depending on the stage. In addition, in the example shown in FIG. 2, a Cu mesh that forms a square gap is used, but the weaving method is not particularly limited, and a Cu mesh that forms a gap of another shape such as a regular triangle or a right triangle is used. Also good. Depending on the position, size, and shape of the voids in the Cu mesh, some of the voids may be closed pores instead of open pores. In this case, Ga does not enter at the initial stage of heat treatment, Remains.

  Thereafter, by performing heat treatment, at least a part of Ga and a part of the Cu mesh are alloyed, and as shown in FIG. 5, a CuGa composite material 55 including a single Cu region and a Ga-containing region can be obtained. . Note that the volume of the single Cu region is reduced by the alloying reaction. Since the amount of impregnation of Ga is different between the inner side and the outer side of the molded body due to the heat treatment, the impregnation of Ga further proceeds on the outer side of the molded body, and the Cu wire part may disappear partially. If the area ratio of the Cu single region is 8% or more in an arbitrary cross section parallel to the target surface to be sputtered, high strength can be ensured. Further, in order to set the Ga concentration gradient to 3.3% by mass / μm or less, it is necessary to control the temperature and time of the heat treatment. However, if the heat treatment is performed excessively, alloying proceeds and the strength is ensured. Since the ratio of the Cu simple substance region which plays a role will fall relatively, heat processing conditions shall be 350 to 750 degreeC in a vacuum, and 0.5 to 5 hours. Preferably they are 500 degreeC-600 degreeC, 1 hour-3 hours. In addition, in order to reduce the influence of the volume change by alloying, you may heat-process under pressure.

  In this heat treatment, in order to form a CuGa alloy at the interface between the Cu simple substance region and the impregnated Ga, the temperature is once raised to a temperature equal to or higher than the precipitation temperature of the CuGa alloy. For example, referring to the binary phase diagram of Cu—Ga alloy shown in FIG. 6 (Source: BINARY ALLOY PHASE DIAGRAMS (ASM International)), up to 260 ° C. of 254 ° C. or up to 650 ° C. of about 645 ° C. You can decide to raise the temperature.

  Further, when the temperature is lowered, the cooling rate is sufficiently lowered near the temperature at which the CuGa alloy phase is precipitated (for example, 490 ° C., 485 ° C., 468 ° C., 254 ° C.), for example, cooling in the range of the precipitation temperature ± 10 ° C. It is preferable to make each CuGa alloy phase easily precipitate at a rate of 10 ° C./min or less. As a result of such temperature control, in the Ga-containing region, a phase having a higher Ga content is formed, for example, in a layered manner from the interface with the Cu simple region toward the inside of the Ga-containing region. For example, as shown in FIG. 7, a γ-phase (γ1, γ2, γ3) layer (low Ga-containing CuGa alloy region) 21 is formed immediately inside the Cu simple substance region 1, and an ε-phase layer (high Ga-containing CuGa alloy region) 22 is formed, and a single Ga layer 23 is formed on the inner side thereof to constitute Ga-containing region 2. Although not shown, an alloy reaction phase having a Ga concentration gradient of 3.3 mass% / μm or less is formed between the γ-phase layer 21 and the Cu element region 1. This alloy reaction phase is considered to be a mixed phase of Cu and the γ phase of the CuGa alloy.

  In the present embodiment, the diameter of the Cu wire of the Cu mesh and the size of the gap are adjusted according to the target Ga content. However, in order to produce a plurality of types of sputtering targets, a plurality of types of Cu are used. A mesh must be prepared. Therefore, the molded body may be obtained by sandwiching the Cu plate between the Cu meshes without overlapping the diameter of the Cu wire and the size of the gap of the Cu mesh.

  For example, as shown in FIG. 8, the Cu mesh 20 and the Cu plate 80 may be alternately stacked to form a molded body. In this case, not only the Cu mesh and the Cu plate are alternately stacked, but the Cu mesh: Cu plate = 2: 1 may be stacked, or two Cu plates may be stacked. Is not particularly limited. Furthermore, the shape of the portion of the Cu mesh where the Cu wires intersect may be a shape in which the wires in the vertical direction and the horizontal direction are connected, but in order to easily impregnate Ga into the voids of the Cu mesh sandwiched between the Cu plates. In addition, it is preferable that the wire in the longitudinal direction and the transverse direction intersect with each other by a step (plain weave).

(Second Embodiment)
As another method for obtaining a molded body, a product in which Cu plates are arranged at equal intervals may be used. For example, a groove of less than 1 mm is dug in a Cu base plate at intervals of 200 μm to 500 μm, and a Cu plate having a thickness of 200 μm to 500 μm is inserted therein to form a molded body. Further, instead of being inserted into the groove, the spacer may be bonded to the base plate by brazing or the like with a spacer of 200 μm to 500 μm, and the spacer may be removed, or the Cu block may be processed with a groove. Alternatively, it may be produced by casting into a mold having a fin shape as a spacer. Since the volume ratio between the thickness of the Cu plate and the interval between the Cu plates becomes the composition ratio, the plate thickness and the plate interval may be adjusted so as to be a predetermined composition ratio. Ga is impregnated in the space between the Cu plates.
The method for impregnating Ga is the same as in the first embodiment.

(Third embodiment)
As another method for obtaining a molded body, Cu wire may be filled into a mold, and pressure may be applied with a press to obtain the molded body. As a method for uniformly dispersing the wire, there is a method in which a spring-like Cu wire is put into a mold and pressed as shown in FIG. The spring-like Cu wire can be produced, for example, by winding the Cu wire around a cylinder having a predetermined diameter several times. The smaller the diameter of the cylinder, the smaller the spring diameter of the Cu wire can be made, and when forming by applying pressure, the Cu wire can be more uniformly dispersed.
The method for impregnating Ga is the same as in the first embodiment.

(Fourth embodiment)
As another method for obtaining a molded body, a hot isostatic press (HIP) method in which Cu powder and Ga powder are mixed at a weight ratio of 35:65 to 80:20. Thus, a sintered body may be obtained as a molded body. As Cu powder used for sintering, atomized powder that tends to be spherical may be used, or electrolytic powder or crushed powder may be used. Further, as the Cu powder, it is preferable to use a powder having an average particle diameter of 100 μm or more in order to leave an unreacted Cu part in the reaction between Cu and Ga.

  Alternatively, an alloy mixture obtained by once melting Cu and Ga at a predetermined ratio and then solidifying the mixture may be pulverized into a powder form. In this case, when preparing the alloy mixture, after making the Cu ratio reduced and making the crushed powder, the reduced amount of Cu powder is mixed with the crushed powder, and the unreacted Cu part is removed. It is preferable to leave it.

  After mixing Cu powder and Ga powder under the above conditions, the mixed powder is sintered by the HIP method. First, the mixed powder is filled into a SUS capsule or the like, and subjected to heat treatment under conditions of 350 ° C. to 750 ° C., 50 MPa to 120 MPa, and 0.5 hours to 5 hours, so that the total volume of the Cu simple substance region and the Cu—Ga alloy region is increased. Thus, a CuGa alloy reaction phase is formed in which the ratio of the single Cu region to 8% by volume or more and a Ga concentration gradient of 3.3% by mass / μm or less are formed.

  Next, experiments conducted by the present inventors will be described. The conditions in these experiments are examples adopted for confirming the feasibility and effects of the present invention, and the present invention is not limited to these examples.

(First embodiment)
First, in order to produce the sample of Example 1, 140 g of a 0.5 mmφ Cu wire wound around a φ5 mm cylinder in the form of a spring was spread on a 110 mm square mold, and a pressure of 300 kgf / cm ² was applied with a uniaxial press. It was hung to obtain a 110 × 110 × 8 mm Cu molded body. This compact was 27% TD, and 73% by volume when Ga was impregnated in this void. Next, 527 g of Ga chips were placed on the compact, and heat treatment was performed at 400 ° C. for 1 hour in a vacuum. After this heat treatment, Ga was impregnated cleanly into the Cu compact, and there was no protrusion. After confirming the impregnation, heat treatment was performed in a vacuum at 550 ° C. for 3 hours. After this heat treatment, the Cu wire reacted and disappeared in some places, and the whole was in the form of a gray metal.

  After the heat treatment, the porosity of the Cu-Ga composite was measured and found to be 0.01% by volume. That is, it was confirmed that Ga was impregnated in almost the entire void portion of the Cu molded body.

  Next, after cutting out a block having a diameter of 4 inches from the center of the Cu—Ga composite, two sputtering targets having a thickness of 3 mm are cut out in parallel with the target surface to be sputtered using a slicer with an inner peripheral blade. It was. In order to cut out 10 targets, processing with such a slicer was performed on 5 blocks. When only 1 sheet was cracked, the remaining 9 sheets were not cracked, and the desired shape of Cu-Ga was formed. A sputtering target was obtained. It is assumed that the yield is good at 90% or more.

  This sputtering target is affixed to a copper backing plate unique to the sputtering apparatus, and the adsorbed water and oxide layer on the surface of the sputtering target are blown off by dummy sputtering with a high-frequency sputtering apparatus (SPF-430HS manufactured by Canon Anelva). The film was formed for 10 minutes. The abnormal discharge was good when it was 3 times or less, but the abnormal discharge was only once during the film formation for 10 minutes.

Further, a sample was cut out from the remaining material of the cut block in order to observe a cross section parallel to the target surface to be sputtered, and was observed with a microscope after polishing / etching treatment. As a result, the simple substance Ga disappeared, and a reaction phase of 10 μm between the CuGa alloy part and the Cu simple substance region could be confirmed. As a result of crystal phase analysis by X-ray diffraction and line analysis by EPMA and EPMA to specify the alloy phase, the CuGa alloy is Cu ₉ Ga ₄ which is a γ phase, and the reaction phase is between Cu and Cu ₉ Ga ₄ . It was considered as a mixed phase, and Ga changed in a gradient composition. The Ga gradient of the reaction phase decreased from 33% by mass to ₉ % by mass of Cu ₉ Ga ₄ and decreased almost linearly at 10 μm, and could be calculated as 3.3% by mass / μm.

  The remaining part of Cu is thinned to 300 μm on average due to the reaction of a 500 μm wire, and a circular, elliptical, and fairly long elliptical (substantially continuous) cut appears in the cross section. The maximum portion was 800 μm. When confirmed with a 1 × 1 mm field of view at a magnification of 500 times, all Cu residues were 8% to 30% in area ratio.

(Second embodiment)
First, under the conditions shown in Table 1 below, samples of Examples 2 to 4 and a sample of Comparative Example 1 were produced by the same procedure as in the first example.

  Next, in order to produce the sample of Example 5, a commercially available Cu mesh (plain woven wire mesh) in which a 0.20 mmφ Cu wire was arranged to be # 40 was cut out at 110 × 8 mm, and the inner diameter was 110 × 110 ×. In a 15 mm quartz crucible, 330 sheets were arranged to obtain a 110 × 110 × 8 mm compact. This compact was 39% TD, and 61% by volume when Ga was impregnated in this void. 310 g of Ga chip was placed on this compact, and heat treatment was performed at 400 ° C. for 1 hour in a vacuum. After this heat treatment, Ga was impregnated cleanly into the Cu compact, and there was no protrusion. After confirming the impregnation, heat treatment was performed in a vacuum at 550 ° C. for 3 hours.

  Next, in order to produce the sample of Example 6, a commercially available Cu mesh (plain woven wire mesh) in which a 0.21 mmφ Cu wire was arranged to be # 60 was cut out at 110 × 8 mm, and this was cut into an inner diameter of 110 × 110 ×. In a 15 mm quartz crucible, 330 sheets were arranged to obtain a 110 × 110 × 8 mm compact. This compact was 42% TD, and 58% by volume when Ga was impregnated in the voids. A 295 g Ga chip was placed on this molded body, and heat treatment was performed at 400 ° C. for 1 hour in a vacuum. After this heat treatment, Ga was impregnated cleanly into the Cu compact, and there was no protrusion. After confirming the impregnation, heat treatment was performed in a vacuum at 550 ° C. for 3 hours. Furthermore, as shown in Table 1 below, samples of Examples 7 to 10 and samples of Comparative Examples 2 and 3 having different heat treatment conditions were similarly produced.

  Next, in order to produce the sample of Example 11, a commercially available Cu mesh (plain woven wire mesh) in which a 0.21 mmφ Cu wire was arranged to be # 60 was cut out at 110 × 8 mm, and similarly 0.42 mm thick Cu The plates were cut into 110 × 8 mm, and these were placed in a quartz crucible having an inner diameter of 110 × 110 × 15 mm, and 170 sets were alternately arranged to obtain a molded body of 110 × 110 × 8 mm. This compact was 53% TD, and 47% by volume when Ga was impregnated in the voids. A 239 g Ga chip was placed on the compact and heat-treated at 400 ° C. for 1 hour in a vacuum. After this heat treatment, Ga was impregnated cleanly into the Cu compact, and there was no protrusion. After confirming the impregnation, heat treatment was performed in a vacuum at 550 ° C. for 3 hours. In addition, samples of Examples 12 to 14 were produced by the same procedure under the conditions shown in Table 1 below.

  Next, in order to fabricate the sample of Example 15, 220 grooves having a width of 300 μm and a depth of 500 μm were formed in a 110 × 110 × 2 mm Cu block at intervals of 200 μm, thereby fabricating a base plate. A Cu plate of 110 × 5.5 × 0.3 mm was inserted into this groove, and a Cu molded body having a Cu thickness of 300 μm and a Cu interval of 200 μm was obtained in the portion excluding the base plate. The portion excluding the base plate of this molded body was 60% TD, and 40% by volume when Ga was impregnated in this void. 216 g of Ga chips were placed on this molded body, and heat treatment was performed at 400 ° C. for 1 hour in a vacuum. After this heat treatment, Ga was impregnated cleanly into the Cu compact, and there was no protrusion. After confirming the impregnation, heat treatment was performed in a vacuum at 550 ° C. for 3 hours. Moreover, the sample of Example 16 was produced in the same procedure under the conditions shown in Table 1 below.

As in the first example, the thickness of the alloy phase, the Ga gradient, the diameter and main shape of the remaining Cu, the spacing and area ratio of the remaining Cu, and the workability evaluation (steps) were performed for all samples prepared in this example. And the number of abnormal discharges. The Ga gradient was calculated from the thickness of the reaction layer and the Ga amount of Cu ₉ Ga ₄ .

  As shown in Table 1, it was confirmed that all the samples according to this example had good workability and little abnormal discharge.

(Third embodiment)
First, in order to prepare the sample of Example 17, 650 g and 350 g of Cu powder having a purity of 4N and 350 g in a mass ratio were put in a 2 liter pot made of resin, and 100 g of a φ10 mm ball coated with an iron ball was added. Ball mill mixed for 1 hour. Then, the mixed powder is filled into a 110 × 110 × 10 mm SUS capsule, vacuum degassed, and then subjected to HIP treatment under the conditions of 400 ° C. × 3 h, 78.5 MPa, and the capsule is ground and removed to be baked at 105 × 105 × 8 mm. A ligature was obtained. Moreover, the sample of Examples 18-20 and the sample of Comparative Examples 4 and 5 were produced on the conditions shown in the following Table 2 with the same procedure.

As in the first example, the thickness of the alloy phase, the Ga gradient, the diameter and main shape of the remaining Cu, the spacing and area ratio of the remaining Cu, and the workability evaluation (steps) were performed for all samples prepared in this example. And the number of abnormal discharges. The Ga gradient was calculated from the thickness of the reaction layer and the Ga amount of Cu ₉ Ga ₄ .

  As shown in Table 2, it was confirmed that all the samples according to this example had good workability and little abnormal discharge. In Comparative Example 4, since the mixed powder was sintered at a low temperature, a large amount of unreacted Ga remained and was melted during processing, resulting in poor workability.

11, 12 1 × 1 mm rectangle 13 circle 20 Cu mesh 30 compact 40 Ga chip 50 void

Claims (8)

Cu single region,
A Ga-containing region adjacent to the Cu single region and containing at least Cu and Ga;
Have
Ga content rate with respect to the total mass of the Cu simple substance region and the Ga-containing region is 20 mass% to 65 mass%,
In any cross section parallel to the target surface to be sputtered, the area ratio of the Cu single region is 8% or more,
A Cu—Ga sputtering target, wherein a Ga concentration gradient in a reaction phase formed between the Ga-containing region and the Cu simple region is 3.3 mass% / μm or less.   Furthermore, the area | region where the area ratio of the said Cu single-piece | unit area | region per 1 * 1mm in the arbitrary cross sections parallel to the target surface sputter | spattered is 8% or more mutually exists at the space | interval within a radius of at least 700 micrometers. Item 8. A Cu-Ga sputtering target according to Item 1.   The γ phase of CuGa alloy is formed in the Ga-containing region, and the reaction phase is a phase formed between the γ phase and the single Cu region. Cu-Ga sputtering target of description. A step of stacking a plurality of meshes made of Cu to obtain a molded body having a porosity of 27.5% by volume to 86% by volume;
Impregnating Ga into voids of the mesh in the molded body;
Forming a CuGa alloy region by reacting the impregnated Ga and the mesh by holding at 350 ° C. to 750 ° C. in vacuum for 0.5 to 5 hours;
A method for producing a Cu-Ga sputtering target, comprising: A step of obtaining a molded body having a porosity of 27.5% by volume to 73% by volume by stacking a plurality of Cu meshes and Cu plates;
Impregnating Ga into voids of the mesh in the molded body;
Forming a CuGa alloy region by reacting the impregnated Ga and the mesh by holding at 350 ° C. to 750 ° C. in vacuum for 0.5 to 5 hours;
A method for producing a Cu-Ga sputtering target, comprising: A step of pressing a spring-like wire to obtain a molded body having a porosity of 27.5% by volume to 73% by volume;
Impregnating Ga into voids of the mesh in the molded body;
Forming a CuGa alloy region by reacting the impregnated Ga and the mesh by holding at 350 ° C. to 750 ° C. in vacuum for 0.5 to 5 hours;
A method for producing a Cu-Ga sputtering target, comprising: Arranging Cu plates at predetermined intervals to obtain a molded body having a volume ratio of 27.5% by volume to 73% by volume of voids between the Cu plates;
Impregnating Ga into the gaps between the Cu plates in the molded body;
Forming a CuGa alloy region by reacting the impregnated Ga and the Cu plate by holding at 350 ° C. to 750 ° C. in vacuum for 0.5 to 5 hours;
A method for producing a Cu-Ga sputtering target, comprising:   In the process of forming the said CuGa alloy area | region, it hold | maintains at 500 to 600 degreeC in vacuum for 1 to 3 hours, The Cu-Ga sputtering target of any one of Claims 4-7 characterized by the above-mentioned. Production method.

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