JP6021596B2 - Indium sputtering target and manufacturing method thereof - Google Patents

Description

  The present invention relates to an indium sputtering target and a manufacturing method thereof.

  Indium is used as a sputtering target for forming a light absorption layer of a Cu—In—Ga—Se (CIGS) thin film solar cell.

Conventionally, indium sputtering targets are mainly manufactured by melt casting.
Japanese Patent Publication No. 63-44820 (Patent Document 1) describes a method in which an indium thin film is formed on a backing plate, and then indium is poured onto the thin film and cast so as to be integrated with the backing plate.
In JP 2010-24474 A (Patent Document 2), a predetermined amount of indium raw material is charged into a heated mold and melted, indium oxide floating on the surface is removed, and cooled to obtain an ingot. When the obtained ingot surface is ground to obtain an indium target, a predetermined amount of indium raw material is charged in a plurality of times without being poured into the mold at once, and the indium oxide on the surface of the molten metal generated is removed each time. A method is described in which the ingot obtained by cooling is surface ground.

Japanese Examined Patent Publication No. 63-44820 JP 2010-24474 A

  However, when a film is formed by magnetron sputtering on the indium target thus obtained, the distribution of the magnetic field on the target is biased due to the structure of the sputtering apparatus. As a result, a region where erosion progresses slowly occurs. In this case, since the usage efficiency of the indium target is determined by the deepest part of the erosion, the target life end is reached even though the region where the erosion progresses slowly is not used so much, and the usage efficiency of the entire target is lowered. There was a problem that.

  For example, in the case of a substantially rectangular target with four corners chamfered as shown in FIG. 2, magnetron sputtering is deepest near both ends (intersection of A line and G line and intersection of E line and G line in FIG. 2). Part is seen. FIG. 3 shows an example of the erosion depth profile along the A line, and FIG. 4 shows an example of the erosion depth profile along the G line.

  Then, this invention makes it a subject to provide the indium sputtering target which can improve the use efficiency of a target, and its manufacturing method.

  The present inventor has intensively studied to solve the above problems, and uses a low sputter rate target member in a region where erosion progresses fast, while a high sputter rate target member applies to a region where erosion progresses slowly. It has been found that the use efficiency of the target member is improved by reducing the difference in the sputtering rate between the region where the progress of erosion is fast and the region where the progress of erosion is slow.

  The present invention completed on the basis of the above knowledge, in one aspect, the crystal structure of indium in a region that is a partial region of the indium target member and that surrounds at least the deepest part of the erosion, It is an indium sputtering target provided with an indium target member having a crystal structure that is less likely to be eroded on average.

In one embodiment of the indium sputtering target according to the present invention, when the crystal structure of indium in the erosion-promoting region including the deepest part of erosion is compared with the crystal structure in the erosion-promoting region, the erosion-promoting region is more It is a crystal structure that is hardly eroded on average.
Here, the erosion facilitating region refers to a target member manufactured by allowing it to cool in a room temperature environment after melting and casting, and the depth of the deepest portion is 50% of the target thickness under standard sputtering conditions defined in the specification. In the erosion profile when sputtering is performed until it reaches 100% or more, when the depth of the deepest part is 100%, the erosion depth of the part is 30% or more and 100% or less. Refers to other areas.

  In another embodiment of the indium sputtering target according to the present invention, a member that is not plastically processed after melt casting is disposed in a region that is a part of the indium target member and that surrounds at least the deepest part of the erosion. In the other region of the target member, a member that has been plastically processed after melt casting is disposed.

  In yet another embodiment of the indium sputtering target according to the present invention, the crystal structure of the surface of the plastic-worked member can be formed when adjacent corners of grain boundaries forming crystal grains are connected with a straight line. A grain boundary with a protrusion in the perpendicular direction of the line segment of less than 0.1 mm, and a structure having a linear grain boundary with a linear region of 50 μm or more, and the cast product has a crystal grain size of 0.1 mm to 5 mm. Is selected from a structure having a crystal grain size of 5 mm or more.

  In still another embodiment of the indium sputtering target according to the present invention, a part of the indium target member that surrounds at least the deepest part of the erosion is a member that is not subjected to plastic working after melt casting and is crystallized. A member having a structure with a grain size of 0.1 mm or more and less than 5 mm is disposed, and a structure that is not plastically processed after melt casting and has a crystal grain size of 5 mm or more in another region of the indium target member. Arrange the member with.

  In yet another embodiment of the indium sputtering target according to the present invention, the indium target member consists of a single member.

  In still another embodiment of the indium sputtering target according to the present invention, the indium target member includes a plurality of members.

  In another aspect, the present invention provides a method for producing an indium target member by melt casting an indium raw material, and at the time of melt casting in a partial region of the indium target member that surrounds at least the deepest erosion part The cooling rate is increased more than the cooling rate during melt casting in other regions of the indium target member.

  In one embodiment of the method for producing an indium target member according to the present invention, plastic processing is performed on a region other than a region that is at least a part of the indium target member and surrounds the deepest erosion portion.

  In another embodiment of the method for producing an indium target member according to the present invention, the plastic working is a method selected from rolling, pressing, and extrusion.

  In still another embodiment of the method for producing an indium target member according to the present invention, indium plastically bonded is bonded to a region other than a region surrounding at least the deepest erosion part of the indium target. Including that.

  The use efficiency of the target can be improved by the present invention.

It is a schematic diagram which shows the example of the planar shape of the disk type indium target member used by the Example and the comparative example. It is a schematic diagram which shows the example of the planar shape of a rectangular type indium target. It is an example of the profile of the erosion depth along A line when the indium target of the shape shown in FIG. 2 is used. 2 is an example of an erosion depth profile along the G line when an indium target having the shape shown in FIG. 2 is used. When using the indium target member having the shape of FIG. 2, it is a schematic diagram showing a state in which a coolant is brought into contact with the erosion-promoting region at the time of casting so that the cooling rate is higher than that of the erosion-progress region.

  In an embodiment, an indium sputtering target including an indium target member according to the present invention has a crystal structure of indium in another region of the indium target member that surrounds at least the deepest erosion portion. The crystal structure is less susceptible to erosion than the crystal structure in the region.

  Since the deepest erosion portion has a high magnetic flux density and the ion causing the sputtering phenomenon frequently collides with the surface of the indium target member, a member that is not easily eroded is used in a certain region surrounding the deepest erosion portion. On the other hand, since the magnetic flux density at the time of sputtering is low in the other regions and the frequency that ions causing the sputtering phenomenon collide with the surface of the indium target member is low, a member that is easily eroded is used in this region. As a result, the difference in the sputtering rate between the region surrounding the deepest erosion part and the other region is alleviated, and the use efficiency of the indium target member is improved.

  The size of the region surrounding the deepest erosion part using a member that is difficult to be eroded may be set as appropriate depending on the shape of the target and the operating conditions of the sputtering apparatus, and is not particularly limited. However, it is not necessary to surround a part far away from the deepest part of the erosion, and a region where the erosion is relatively fast may be used. For example, a predetermined condition (hereinafter referred to as “standard target member”) for a target member (hereinafter referred to as “standard target member”) having a predetermined shape (for example, a rectangular shape or a disk shape) manufactured by allowing to cool in a room temperature environment (25 ° C.) after melt casting. The sputtering conditions at this time are referred to as “standard sputtering conditions”), and when the depth of the deepest portion is set to 100% in the erosion profile when sputtering is performed until the depth of the deepest portion is 50% or more of the target thickness. In addition, when an area where the erosion depth of the portion is 30% or more and 100% or less is an erosion-promoting area and the other area is an erosion-progressing area, a member that is not easily eroded with respect to the erosion-promoting area is obtained. It is possible to use a member that is easily eroded in the erosion difficult progress region.

Here, the standard sputtering conditions are as follows.
・ Sputtering equipment: DC magnetron sputtering equipment ・ Sputtering gas: Ar
・ Sputtering gas pressure: 0.5Pa
・ Sputtering gas flow rate: 50 SCCM
Sputtering temperature: T.A. (No heating)
・ Sputtering power density: 1.1 W / cm ²

  Therefore, in one embodiment of the indium target member according to the present invention, when the crystal structure of indium in the erosion-promoting region and the crystal structure in the erosion-prone region are compared, the erosion-promoting region is more resistant to erosion. Therefore, when the sputtering is performed under the same conditions, the average sputtering rate is slow and the crystal structure is difficult to erosion.

  In one embodiment of the indium target member according to the present invention, when comparing the erosion profile when sputtered under standard sputtering conditions with the standard target member, the indium target member according to the present invention having the same shape as the standard target member is more The difference between the erosion depth in the erosion difficult progress region and the erosion depth in the erosion easy progress region is small on average.

  Although it may be possible to extend the life of the target by increasing the thickness of the erosion-prone area compared to the non-erosion-prone area, there is a step at the boundary between the thick and thin areas, which causes arcing during sputtering. Further, it is preferable that the plate thickness of the target member is constant because it may cause chain growth of nodules.

  Indium sputtering targets have different resistance to erosion depending on the crystal structure. Specifically, when the structures of the sputtering targets made of indium are arranged in the order in which erosion is likely to occur, that is, in the descending order of the sputtering rate, the plastic working structure >> casting structure (crystal grain size)> casting structure (crystal grain size). By utilizing this characteristic, a target member having a cast structure (low rate) is placed in a region where erosion is likely to occur, and a target member having a plastic texture (high rate) is placed in a region where erosion is difficult, or a region where erosion is likely to occur. By placing a target member having a cast structure with a small crystal grain (low rate) and a target member having a large cast structure (high rate) in a region where erosion is difficult to occur, an erosion easily progressing region and an erosion difficult progress region The sputtering rate difference between the two is reduced, and the use efficiency of the target member is improved.

  The target member having a plastic working structure can have crystal grains having a linear grain boundary on the surface subjected to sputtering, in which the average grain diameter of crystal grains in surface observation is in the range of 0.1 to 40 mm. Further, in the target member having a plastic working structure, the influence of the particle diameter is smaller than the difference in the film forming rate between the plastic working product and the cast product. On the other hand, for a target member having a cast structure, with respect to the average particle diameter of crystal grains in surface observation, if the average particle diameter is defined as large crystal grains of 5 mm or more and small crystal grains of 0.1 mm or more and less than 5 mm, It is preferable that the target member having a small particle size is disposed in a region where erosion is difficult and the target member having a small particle size is disposed in a region where erosion is likely to occur. Further, a larger difference in average particle size between large crystal grains and small crystal grains is preferable for increasing the use efficiency of the target. For example, a difference of 10 mm or more is desirable, and a difference of 20 mm or more is more desirable. . However, since it is difficult to make an excessively large crystal grain, it is generally 40 mm or less, and typically a difference of 30 mm or less.

In the present invention, the average diameter of the crystal grains of the target member is measured as follows. The surface of the target member to be measured is photographed with a digital camera, and the number (N) of crystal grains existing in an arbitrary region (arbitrary shape and area S of 2500 mm ² ) of the surface of the image is counted. In order to make the surface easy to see, polishing, electrolytic polishing, or etching may be used. However, the number of crystal grains existing across the boundary of the region was 0.5. The average area (s) of the crystal grains is calculated by dividing the area (S) of the measurement target region by N. Assuming that the crystal grains are spheres, the average crystal grain size (A) is calculated by the following formula.
A = 2 (s / π) ^1/2

In the present invention, the term “linear grain boundary” means that the protrusion in the perpendicular direction of the line segment formed when the adjacent corners of the grain boundary forming the crystal grain are connected by a straight line on the surface subjected to sputtering is less than 0.1 mm. The grain boundary is This evaluation is performed on an image photographed at a magnification of 50 times with a digital microscope, and the thickness of the line segment to be evaluated is 0.01 mm. Further, the straight line means a case where there is a linear region of 50 μm or more, and when it is less than 50 μm, it is not included in the straight line. When the grain boundary is made easier to see by etching, the grain boundary may be scraped depending on the degree of etching, but the linear shape is not impaired. Therefore, in the present invention, in such a case, the side edge of the cut grain boundary is defined as the grain boundary in the crystal grain to be observed.
In the present invention, “a crystal grain having a linear grain boundary” is a crystal grain having a grain boundary satisfying the definition of the linear grain boundary in one or more of the grain boundaries forming the crystal grain.

  The straight grain boundary must be observed in such a way that the structure is sufficiently visible. For example, the work-affected layer present on the target surface is removed and observed by etching with acid, electropolishing, sputtering, or the like. Observation may be performed by visual observation, or a digital camera, digital microscope, electron microscope, or the like may be used.

  The greater the difference in erosion susceptibility between the target members used in the erosion-prone region and the erosion-prone region, the more the difference in sputter rate between the erosion-prone region and the erosion-prone region is reduced. . Therefore, in a preferred embodiment of the present invention, a target member having a cast structure (small crystal grains) can be disposed in the erosion-promoting region, and a target member having a plastic working structure can be disposed in the erosion-promoting region.

  The plastic working structure can be produced by rolling, pressing, and extruding an ingot obtained by melt casting. The total rolling reduction is preferably 15% or more, and the total rolling reduction is 35% or more. It is more preferable that the total rolling reduction is 50% or more. The total rolling reduction is not particularly limited, but is generally 95% or less, preferably 93% or less, and more preferably 90% or less, because the effect of improving the film formation rate is saturated.

  As described above, the indium target member used in the present invention changes the crystal structure depending on the site, but it can also be composed of a plurality of members or a single member.

In the case of being composed of a plurality of members, for example, a plurality of indium target members having different erosion susceptibility are prepared, and a target member having a crystal structure that is relatively resistant to erosion is surrounded by the deepest part of the erosion, preferably On the other hand, the target member having a crystal structure that is relatively susceptible to erosion can be disposed in another region, preferably in the erosion difficult progress region, while being disposed in the erosion easy progress region. In this case, the divided target members are arranged on the backing plate to constitute the sputtering target. Each member is preferably bonded with an adhesive such as a brazing material so as not to be separated.

  It is the simplest to prepare two types of indium target members, one type for the region surrounding the deepest part of the erosion and one type for the other region. Depending on the frequency at which ions that cause spattering sometimes reach the target member, these regions are further divided, and the average diameter in the plate thickness direction of the crystal grains is increased stepwise from the region where the arrival frequency is high to the region where it is low. You can also do it. Thereby, the difference in the sputtering rate between the erosion region and the non-erosion region is further reduced, and the use efficiency of the indium target member and the degree of improvement in the uniformity of the sputtered film can be increased.

  However, since the erosion easy progress region and the erosion difficult progress region also change depending on the sputtering conditions, if the region is divided very finely according to the sputtering conditions, a sufficient effect can be exhibited only under the specific sputtering conditions, and the target member The versatility will be reduced. Moreover, it is not preferable to change the target member according to the sputtering conditions in consideration of productivity and economy. Therefore, it is not necessary to divide it excessively, and it is appropriate to keep it in about 2 to 4 areas even when each area is further divided.

In the case of a single member, a crystal structure that is relatively less susceptible to erosion is disposed in a region surrounding the deepest part of the erosion, preferably an erosion- promoting region, while a crystal structure that is relatively susceptible to erosion is disposed. It can be arranged in another area, preferably an erosion difficult progress area. In this case, a single target member having no connection portion is arranged on the backing plate to constitute the sputtering target. In the method using a plurality of target members described above, since the target members are divided, a gap is formed between adjacent target members, and this gap may cause arcing during sputtering. However, such a problem does not occur in the case of a single member because there is no division.

  In the case of a single member, for example, there is a method of changing the crystal grains by changing the cooling rate during casting between the erosion-promoting region and the erosion-promoting region. If the cooling rate during casting is high, the crystal grain size tends to be fine. Therefore, the cooling rate may be increased in the region surrounding the deepest erosion portion, and the cooling rate may be decreased in the other regions. This can be achieved, for example, by bringing a coolant having a higher cooling effect than the other regions into contact with the surface of the region surrounding the deepest erosion portion. FIG. 3 is a schematic cross-sectional view of the target member. Here, a state is shown in which a cooling medium is brought into contact with the erosion easily progressing region at the time of casting so that the cooling rate is higher than that of the erosion difficult progressing region.

  It is simplest to divide the crystal structure into two stages by setting two types of cooling rates for the region surrounding the deepest part of the erosion and for other regions. These regions are further divided according to the frequency with which ions that cause the sputtering phenomenon at the time of sputtering reach the target member, and the cooling rate is reduced from the region with high arrival frequency to the region with low erosion. You can also change the ease step by step. However, as described in the explanation of the first means, since the versatility of the target member is reduced if the area is divided too finely, even when each area is further divided, about 2 to 4 areas are provided. It is reasonable to keep it at

  Moreover, it is also possible to increase a linear grain boundary by rolling or pressing a part or every part. Partial plastic working is possible.

  Next, a preferred example of the method for producing an indium target according to the present invention will be described step by step. First, indium which is a raw material is dissolved and poured into a mold. The raw material indium to be used preferably has a high purity because the conversion efficiency of a solar cell produced from the raw material is reduced when impurities are contained. For example, 99.99 mass A raw material having a purity of at least% can be used. Then, it cools to room temperature and forms an indium ingot.

  By changing the cooling rate at this time, the crystal structure is made differently and the average grain size of the crystal grains is controlled. Furthermore, the crystal structure is controlled by plastic working. When the plastic working is performed, the above-described linear grain boundary develops, so that it can be easily distinguished from the cast structure. When manufacturing a divided target member, the cooling rate and the presence or absence of rolling are set for each target member, and when manufacturing an integrated target member, the cooling rate is set for each part. The control of the structure and the average diameter is mainly performed from the time when the heating of indium in the liquid state is finished and the cooling is started and the indium material temperature (molten metal) reaches 166 ° C. until the indium material temperature reaches 156 ° C. (Hereinafter referred to as “phase change completion time”). The phase change completion time can be controlled by changing the type and temperature of the refrigerant in contact with the material surface. Although there is no restriction | limiting in particular as a refrigerant | coolant, Cold air, water, ice, oil, alcohol, etc. are mentioned.

  The cooling rate for melting and casting for the region surrounding the deepest part of erosion is that the effect of slowing the sputter rate (erosion resistance) is insufficient if the crystal grain size is not sufficiently refined, so the phase change completion time Is preferably within 30 seconds, more preferably within 20 seconds. The phase change completion time is more preferably within 10 seconds, even more preferably within 8 seconds, and most preferably within 5 seconds. Although there is no lower limit in particular, it is generally 1 second or more, and typically 3 seconds or more, because it is costly to increase the cooling capacity.

  On the other hand, the cooling rate during melt casting for other regions may be slower than the phase change completion time during melt casting in the erosion region in order to make the grains coarser than the erosion region. In order to sufficiently obtain the effect of speeding up the cooling, it is preferable that the cooling is performed so as to be 60 seconds or longer, more preferably 90 seconds or longer than the phase change completion time during melting and casting in the erosion region. The cooling rate during melt casting for the other regions can typically be 90 seconds or more, more typically 120 seconds or more. Although there is no particular upper limit, it is generally 1500 seconds or less and typically 1000 seconds or less from the viewpoint of production efficiency.

  The thickness of the target is not particularly limited and may be appropriately set according to the sputtering apparatus to be used, the film formation use time, and the like, but is usually about 3 to 30 mm, and typically about 5 to 20 mm.

  The indium target member obtained in this way can be bonded to the backing plate via a bonding material to form a sputtering target. Moreover, if the indium melt | dissolved at the time of melt | dissolution casting is poured on a backing plate and it cools, a bonding material will become unnecessary. The indium sputtering target thus obtained can be suitably used as a sputtering target for preparing a light absorption layer for a CIGS thin film solar cell.

  Examples of the present invention will be described below together with comparative examples, but these examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

<Comparative Example 1>
A cylindrical mold having an inner diameter of 205 mm and a height of 15 mm is fixed on a copper disk-shaped backing plate having a diameter of 226 mm and a thickness of 5 mm, and an indium raw material (purity 4N) melted at 200 ° C. is deepened to a depth of 10 mm. After pouring, the mixture was allowed to cool in a temperature environment of 25 ° C., and the lathe was removed after removing the mold to form a disk-shaped indium sputtering target (diameter 203 mm × thickness 5 mm). The phase change completion time and the average crystal grain size at this time were as shown in Table 1.

The average crystal grain size was measured by the following method.
The obtained indium target surface was etched with hydrochloric acid to make the grain boundaries easy to see. Of the surface, one arbitrary place to be measured was photographed with a digital camera and measured by the method described above.

Next, the obtained indium sputtering target was sputtered under the following sputtering conditions until the depth of the deepest part was about 4.5 mm. A region where erosion was as severe as the deepest erosion part (B in FIG. 1) appeared concentrically. The erosion deepest part on the line passing through the target center, points 10 mm apart from the deepest part to the left and right (A and C in FIG. 1), and points symmetric to the target centers of A, B, and C (D, E, F) ) In total, and the use efficiency was calculated from the weight loss before and after sputtering. The region 2 shown in FIG. 1 is a region including a region that is eroded by 30% to 100% when the deepest part depth is 100%, that is, an erosion easily progressing region, and has a radius of 58. This is an annular region surrounded by a circle having a radius of 6 mm and a radius of 70.6 mm. This region 1 was a portion other than the region 2 in the target. The input sputtering power density described in the following sputtering conditions is a value obtained by dividing the output during sputtering by the area of the sputtering surface of the target.
The sputtering conditions are as follows.
Sputtering device: DC magnetron sputtering device (manufactured by Canon Anelva, SPF-313H)
・ Target size: 203mm × 5mmt
・ Sputtering gas: Ar
・ Sputtering gas pressure: 0.5Pa
・ Sputtering gas flow rate: 50 SCCM
Sputtering temperature: T.A. (No heating)
・ Sputtering power density: 1.1 W / cm ²
-Substrate: Corning Eagle 2000, φ4 inch x 0.7 mmt

  Table 1 shows the measurement results of Comparative Example 1. The use efficiency was 15.0%.

<Example 1>
A cylindrical mold having an inner diameter of 205 mm and a height of 15 mm is fixed on a copper disk-shaped backing plate having a diameter of 226 mm and a thickness of 5 mm, and an indium raw material (purity 4N) melted at 200 ° C. is deepened to a depth of 10 mm. Poured. Furthermore, in order to develop a fine crystal structure from the surface to the backing plate only in the erosion-promoting region (region 2 in FIG. 1), water is poured into a cooling bat having the same shape as the bottom surface and pressed from the surface side. Forced water cooling. As soon as solidification in region 2 was confirmed, the cooling vat was removed. Then, it stood to cool like other area | regions. Thereafter, the mold was removed and turned to form a disk-shaped indium target (diameter 203 mm × thickness 5 mm). The phase change completion time at this time and the average value of the crystal grain size were as shown in Table 2.
The sputter test was performed in the same manner as in Comparative Example 1. The measurement results are shown in Table 2.

  Compared to Comparative Example 1, it can be seen that the erosion of the erosion difficult progress region 1 is deeper. The usage efficiency of this target increased to 15.3%. Note that it is easily expected that the effect is further increased in a rectangular target having a large erosion area.

<Example 2>
A cylindrical mold having an inner diameter of 205 mm and a height of 15 mm is fixed on a copper disk-shaped backing plate having a diameter of 226 mm and a thickness of 5 mm, and an indium raw material (purity 4N) melted at 200 ° C. is deepened to a depth of 10 mm. Poured. Furthermore, in order to develop a fine crystal structure from the surface to the backing plate only in the erosion region (region 2 in FIG. 1), ice water is put into a cooling bat having the same shape as that of region 2 and pressed from the surface side. Ice-cooled. As soon as solidification in region 2 was confirmed, the cooling vat was removed and the other regions were allowed to cool. Thereafter, the mold was removed and turned to form a disk-shaped indium target (diameter 203 mm × thickness 5 mm). The phase change completion time at this time and the average value of the crystal grain size were as shown in Table 3.
The sputter test was performed in the same manner as in Comparative Example 1. Table 3 shows the measurement results.

  Compared to Comparative Example 1, it can be seen that the erosion of the erosion difficult progress region 1 is deeper. The use efficiency of this target was 15.6%. Since the difference in resistance to erosion between the members in the region 1 and the members in the region 2 was larger than that in the example 1, the use efficiency was higher than that in the example 1.

<Example 3>
A total of two sheets (one disk and one ring) were cut out in the shape of region 1 in FIG. 1 from an indium plate rolled to 6 mm after producing a 40 mm indium ingot by melt casting (cooling). Moreover, the ingot produced with the thickness of 6 mm by casting (cooling) to the shape (annular) of the area | region 2 was cut out. Each member was bonded with a brazing material, and a disk-shaped indium target (diameter 203 mm × thickness 5 mm) was formed by lathe processing. The phase change completion time and the average value of the crystal grain size at this time were as shown in Table 4. Moreover, when the surface to be sputtered of the member manufactured by rolling was etched with hydrochloric acid and observed with a digital camera, linear grain boundaries were developed.

  The sputter test was performed in the same manner as in Comparative Example 1. Table 4 shows the measurement results.

  Compared to Comparative Example 1, it can be seen that the erosion of the erosion difficult progress region 1 is deeper. The use efficiency of this target was 16.1%. Since the difference in resistance to erosion between the members in the region 1 and the members in the region 2 was larger than that in Example 2, the use efficiency was higher than that in Example 2.

<Example 4>
A total of two sheets (one disk and one ring) were cut out in the shape of region 1 in FIG. 1 from an indium plate rolled to 6 mm after producing a 40 mm indium ingot by melt casting (cooling). Moreover, the ingot produced with the thickness of 6 mm by the casting (ice cooling) to the shape (annular) of the area | region 2 was cut out. Each member was bonded with a brazing material, and a disk-shaped indium target (diameter 203 mm × thickness 5 mm) was formed by lathe processing. The phase change completion time and the average value of the crystal grain size at this time are shown in Table 5. Moreover, when the surface to be sputtered of the member manufactured by rolling was etched with hydrochloric acid and observed with a digital camera, linear grain boundaries were developed.
The sputter test was performed in the same manner as in Comparative Example 1. Table 5 shows the measurement results.

  Compared to Comparative Example 1, it can be seen that the erosion of the erosion difficult progress region 1 is deeper. The use efficiency of this target was 16.7%. Since the difference in resistance to erosion between the members in the region 1 and the members in the region 2 was further increased as compared with Example 3, the use efficiency was higher than that in Example 3.

11, 21 Backing plate 12, 22 Sputtering target

Claims (11)

  An indium target member having an indium crystal structure in a partial region of the indium target member and at least a region surrounding the deepest erosion portion, which is less easily eroded on average than the crystal structure in other regions of the indium target member An indium sputtering target comprising: 2. The crystal structure of indium in the erosion-promoting region including the deepest part of erosion is compared with the crystal structure in the erosion-promoting region, and the erosion-promoting region has a crystal structure that is less easily eroded on average. The indium sputtering target described.
Here, the erosion facilitating region refers to a target member manufactured by allowing it to cool in a room temperature environment after melting and casting, and the depth of the deepest portion is 50% of the target thickness under standard sputtering conditions defined in the specification. In the erosion profile when sputtering is performed until it reaches 100% or more, when the depth of the deepest part is 100%, the erosion depth of the part is 30% or more and 100% or less. Refers to other areas. A member that is not plastically processed after melt casting is disposed in a part of the indium target member that surrounds at least the deepest part of erosion, and a member that is plastically processed after melt casting in the other region of the indium target member The manufacturing method of the indium sputtering target of Claim 1 or 2 including arrange | positioning. Grain boundary in which the crystal structure of the surface of the plastically processed member is less than 0.1 mm in the perpendicular direction of a line segment formed when adjacent corners of the grain boundary forming a crystal grain are connected by a straight line And a structure having a linear grain boundary with a linear region of 50 μm or more, and the non- plastic processed member has a structure in which the crystal grain size is 0.1 mm or more and less than 5 mm, and the crystal grain size is 5 mm or more. The manufacturing method of the indium sputtering target of Claim 3 selected from a certain structure | tissue. A part of the indium target member that surrounds at least the deepest part of the erosion is a member that is not plastically processed after melt casting and has a structure with a crystal grain size of 0.1 mm or more and less than 5 mm. 3. The indium according to claim 1 , further comprising disposing a member that is not plastically processed after melt casting and has a structure having a crystal grain size of 5 mm or more in another region of the indium target member. A method for producing a sputtering target. Indium target member, indium sputtering target according to claim 1 or 2 consisting of a single member. Indium target member, indium sputtering target according to claim 1 or 2 comprising a plurality of members.   A method for producing an indium target member by melting and casting an indium raw material, wherein a cooling rate at the time of melt casting in a partial region of the indium target member and surrounding at least the deepest erosion portion is determined by A method including increasing the cooling rate during melt casting in another region.   The method according to claim 8, further comprising plastically processing an area of the indium target member other than an area surrounding at least the deepest erosion portion. The method according to claim 9, wherein the plastic working is a method selected from rolling, pressing, and extrusion.   9. The method according to claim 8, comprising bonding indium plastically processed to a region of the indium target other than at least a region surrounding the deepest erosion portion.