JP5540948B2 - Sputtering target - Google Patents

Description

  The present invention relates to a sputtering target used for manufacturing a recording layer or the like of a magnetic recording medium.

  As a sputtering method for producing a recording layer or the like of a magnetic recording medium, in recent years, a magnetron sputtering method in which a magnetic field is applied to a target has become mainstream. The magnetron sputtering method enables high-speed film formation by sputtering in a concentrated manner by applying a voltage with a magnet placed on the back side of the target and converging the plasma in a magnetic flux region that leaks to the surface of the target. (See Patent Document 1).

  Sputtering conditions in a magnetron sputtering apparatus have become stricter as the apparatus becomes larger and has higher performance. For this reason, a large number of coarse particles are generated even in a short operation, and there is a problem of shortening the life of the target due to the particles.

  On the other hand, in order to prevent the sputtered product deposited on the non-erosion region (non-sputtered portion) of the sputtering surface of the target from peeling and becoming particles, the non-erosion is compared with the erosion region (sputtered portion). It has been proposed to increase the surface roughness of the region so that the sputtered product adheres to the non-erosion region and does not peel off (see Patent Document 2).

JP 62-60867 A JP-A-6-306597

  On the sputtering surface of the target, the erosion region is formed in a ring shape, and the non-erosion region surrounds the periphery. For this reason, even if the non-erosion region is roughened and the sputter product is adhered, the sputter product adhering to the non-erosion region is re-sputtered near the erosion region to generate particles and contaminate the sputtered film. This may cause

  This invention is made | formed in view of such a situation, and it aims at suppressing generation | occurrence | production of the particle | grains of a sputtering target in a magnetron sputtering apparatus.

The present invention, ZnO to become by the 0.1～3.0Wt% or Ga ₂ O ₃ and Al ₂ O ₃ was added 0.5~6.0wt%, oxidation of AZO-based or GZO system used in the magnetron sputtering A surface target (sputter surface) having a surface roughness of Ra 1.0 μm or less and set to an erosion region to be sputtered and a non-sputtered non-erosion region, the non-erosion region being the erosion region A first non-erosion region having a surface roughness Ra of 3.0 μm to 6.0 μm and a region between the first non-erosion region and the erosion region and having a surface roughness of Ra1. It is 0 μm or less, and is set to a second non-erosion region provided with a width of 5 to 15 mm around the erosion region

  According to this sputtering target, since the first non-erosion region is roughened, the sputter product adhering to the first non-erosion region is firmly fixed and can be prevented from being peeled off. Generation can be effectively suppressed.

  In this case, the lower limit of the surface roughness of the first non-erosion region is set to Ra 3.0 μm in order to ensure sufficient adhesion between the sputtering target and the sputtered product, and the upper limit Ra 6 to prevent abnormal discharge. .0 μm is set.

In addition, since the second non-erosion region between the first non-erosion region and the erosion region is set to be a smooth surface, it is difficult to increase the thickness even if the sputter product adheres to the second non- erosion region, By being set in a narrow area of 5 to 15 mm, the attached sputtered product is difficult to peel off. That is, the reason why the width of the second non-erosion region is set to 5 mm or more is to prevent the adhered sputtered product from being re-sputtered due to the influence of the erosion space. The reason why the width is set to 15 mm or less is to prevent the sputtered product adhering to the second non-erosion region from becoming excessively large and peeling off.

  In this sputtering target, it is preferable that the first non-erosion region is provided so as to be separated from an edge portion of the sputtering target. In this case, since the surface roughness of the edge part of a sputtering target is small, generation | occurrence | production of a crack and a chip | tip here and abnormal discharge can be suppressed.

  According to the present invention, in magnetron sputtering, generation of particles due to sputter products can be suppressed, and high-quality film formation can be achieved.

It is a figure which shows the surface (sputtering surface) of the sputtering target of this invention. It is a side view which shows a magnetron sputtering apparatus provided with the sputtering target which concerns on this invention. It is sectional drawing which follows the AA line in FIG.

Hereinafter, embodiments of the sputtering target according to the present invention will be described. This sputtering target 10 is formed by adding 0.1 to 3.0 wt% of Al ₂ O ₃ or 0.5 to 6.0 wt% of Ga ₂ O ₃ to ZnO, and is an AZO-based oxide used for magnetron sputtering. As shown in FIG. 1, the target is a rectangular plate-like material in which a surface 10a is a sputter surface and a rectangular hole 10b is formed at the center.

  Here, the magnetron sputtering apparatus 100 using the sputtering target 10 will be described. As shown in FIG. 2, the magnetron sputtering apparatus 100 holds a sputtering target 10 in a vacuum chamber 101, a stage 103 that holds a processing substrate 102 in a lower state of the vacuum chamber 101, and an upper portion of the vacuum chamber 101. The target holder 104 is provided.

  The processing substrate 102 and the sputtering target 10 face each other vertically with a space therebetween. Inside the target holder 104, a magnet 105 disposed on the back surface of the sputtering target 10 is provided.

  The target holder 104 is attached to the wall of the vacuum chamber 101 in an insulated state, and is connected to an external power source 106 for applying a voltage to the sputtering target 10. The vacuum chamber 101 is provided with a gas inlet 101a for introducing an inert gas such as Ar gas, and a gas outlet 101b for exhausting and evacuating.

  In the magnetron sputtering apparatus 100, when the vacuum chamber 101 is kept in a vacuum state, a voltage is applied between the sputtering target 10 and the processing substrate 102 from the external power source 106, and an inert gas is introduced into the vacuum chamber 101. The magnetic field from the magnet 105 on the back of the sputtering target 10 leaks to the surface 10a side of the sputtering target 10 as shown by the two-dot chain line.

  As a result, the discharge plasma converges on the surface 10a of the sputtering target 10 with high density as shown by the broken line. When ions of the inert gas are accelerated in this plasma and enter the sputtering target 10, sputter atoms are knocked out from the surface 10 a of the sputtering target 10 to reach the processing substrate 102, and a thin film is formed on the surface of the processing substrate 102. Is done.

  As shown in FIG. 1, the surface 10 a of the sputtering target 10 used in the magnetron sputtering apparatus 100 has a surface roughness Ra of 1.0 μm or less and a sputtered erosion region 20 and a non-sputtered non-erosion region 21. Is set. FIG. 3 shows a cross section of the sputtering target 10 along the line AA in FIG.

  The non-erosion region 21 is separated from the erosion region 20 and has a first non-erosion region (rough surface region) 21 a having a surface roughness of Ra 3.0 μm to 6.0 μm, and the first non-erosion region 21 a and the erosion region. 20 and a second non-erosion region (smooth surface region) 21b provided with a width of 5 to 15 mm around the erosion region 20 and having a surface roughness Ra of 1.0 μm or less. Is set.

  The first non-erosion region (rough surface region) 21 a is provided so as to be separated from the end edge portion 10 c of the sputtering target 10 by, for example, 1 to 2 mm. In other words, a smooth edge region 21c having a width of 1 to 2 mm from the edge portion 10c and a surface roughness of Ra 0.1 μm to 1.0 μm and not sputtered is provided. In addition, the edge part 10c here is the outer peripheral part of the sputtering target 10, and the peripheral part of the rectangular hole 10b, as shown in FIG.

  The surface 10a of the sputtering target 10 is processed into the desired surface roughness described above, for example, by the following process. That is, first, the entire surface 10a is polished so that Ra is 1.0 μm or less. Thereby, the smooth surface region 21b and the smooth edge region 21c of the erosion region 20 and the non-erosion region 21 are set to have desired surface roughness.

  Next, the erosion region 20, the smooth surface region 21b, and the smooth edge region 21c are masked and subjected to blasting so that Ra becomes 3.0 μm to 6.0 μm, and the rough surface region 21a is roughened to a desired surface roughness. Turn into. At this time, since the blasting is not performed on the region having a width of 1 to 2 mm (that is, the smooth edge region 21c) from the edge portion 10c where the chipping is likely to occur, the abnormal discharge due to the chipping of the sputtering target 10 can be prevented.

  When the entire surface 10a of the sputtering target 10 is processed by surface grinding, columnar crystals are likely to be formed due to the direction of processing scratches, and the sputtered product attached along this crystal direction may be easily peeled off. is there. However, the surface shape is randomized by blasting, thereby preventing the sputtered product from peeling off.

  When the sputtering target 10 is sputtered using the magnetron sputtering apparatus 100, the erosion region 20 of the sputtering target 10 is sputtered, and a sputtered product is generated by sputtering and adheres to the surface 10 a of the sputtering target 10. Note that the sputtered product includes particles generated from the sputtering target 10, components that did not reach the processing substrate 102 and were not deposited, and the like.

  The sputtered product is thick and easily adheres to the rough surface area 21a, but since the adhesion force to the rough surface is strong, there is little possibility that the processed substrate 102 is peeled off and contaminated. Further, the smooth surface region 21b having a width of 5 to 15 mm and the smooth edge region 21c having a width of 1 to 2 mm which are adjacent to each other so as to surround the erosion region 20 are thick because the sputter product is a smooth surface. Difficult to peel off due to narrow area. Since the thickness of the adhering sputtered product is relatively small and about 0.1 mm, the sputtered product adhering thereto hardly prevents the erosion region 20 from being sputtered or re-sputtered to generate particles. .

As described above, according to the sputtering target 10 according to the present invention, it is difficult to drop off the sputtered product attached by sputtering, and resputtering of the attached sputtered product does not easily occur. Film formation by magnetron sputtering over a long time is possible.
In addition, this invention is not limited to the thing of the structure of the said embodiment, In a detailed structure, it is possible to add a various change in the range which does not deviate from the meaning of this invention.

(Examples and Comparative Examples)
Here, examples and comparative examples of the sputtering target according to the present invention will be described.

(AZO-based sputtering target)
First, for Examples A1 to A4 and Comparative Examples A1 to A6 in the AZO-based sputtering target, each surface roughness of the erosion region, the first non-erosion region, and the second non-erosion region, and the width of the second non-erosion region The distance from the first non-erosion region to the edge of the sputtering target was varied as shown in Table 1.

First, sputtering targets in AZO-based Examples A1 to A4 and Comparative Examples A1 to A6 were prepared as follows. That is, as a raw material powder, commercially available ZnO powder and Al ₂ O ₃ powder having an average particle diameter of 0.5 μm and a purity of 99.9% or more were prepared. These raw material powders were blended so that ZnO was 98.0% by mass and Al ₂ O ₃ was 2.0% by mass. It was.

After drying the obtained mixed powder, it is filled into a rubber mold and subjected to cold isostatic pressing under a pressure of ² Ton / cm ² to produce a molded body. The molded body has a diameter of 180 mm and a thickness of 20 mm. It processed into the disk-shaped molded object which has a dimension, and obtained the disk-shaped molded object. The obtained disk-shaped molded body was heated at 1400 ° C. in the atmosphere to produce a sintered body having a theoretical density ratio of 95% or more. Furthermore, the obtained sintered body was ground to produce an AZO-based sputtering target having a diameter of 125 mm and a thickness of 10 mm. The composition of the target is 2.0% by mass for Al ₂ O _{3 and} 98.0% by mass for ZnO by ICP analysis.

The adjustment method of the surface roughness of the sputtering target in each Example and Comparative Example is, for example, as follows. That is, with an abrasive (mainly # 46 in accordance with JIS rules) containing alumina (Al ₂ O ₃ ) as a blast grain, the blast injection pressure is 0.3 ± 0.05 MPa, and the blast time is 30 to 90 seconds. Blasting. The injection pressure and blasting time vary depending on the blasting device used.

  A mask made of a vinyl chloride plate is fixed to a portion of the sputtering target that is not blasted. Masking can also be performed with an adhesive tape, a metal mask, or the like. Blasting may cause abrasive particles to adhere to the target, which is removed by ultrasonic cleaning.

Then, the sputtering targets of Examples A1 to A4 and Comparative Examples A1 to A6 were used for sputtering with a DC sputtering apparatus with a sputtering time of 1 hour, a power density of 10 Wh / cm ² , a sputtering time of 1 hour, and an integrated power amount of 10 WHr / cm ² . The evaluation test to be used was conducted. Each sputtering target is confirmed in advance by X-ray transmission images after bonding to be free of bonding defects, cracks and cracks. Table 2 shows the number of occurrences of abnormal discharge during sputtering, the presence or absence of cracks in the target, and the presence or absence of peeling of the film attached by sputtering.

  In addition, the presence or absence of the generation | occurrence | production of a crack was confirmed visually after the target was ultrasonically cleaned. Further, the number of abnormal discharges was counted as the cumulative number of arcing during the sputtering.

  The sputtering targets of Examples A1 to A3 were confirmed to be capable of film formation by magnetron sputtering over a long period of time without any abnormal discharge, cracks, and peeling of the attached film, and without reducing film formation performance.

  In Example A4, the first non-erosion region is provided without being separated from the edge of the sputtering target. That is, the surface roughness of the edge portion of the sputtering target is large. Although no crack was seen from the appearance, two abnormal discharges occurred due to the large surface roughness up to the edge.

  In the sputtering target of Comparative Example A1 in which the width of the second non-erosion region was too small, abnormal discharge occurred six times when the processing time passed during sputtering. Further, since resputtering occurs, particles are generated, which may cause contamination of the sputtered film.

  On the other hand, in the sputtering target of Comparative Example A2 in which the width of the second non-erosion region is too large, since the film attached to the second non-erosion region is peeled off, the peeled material may become particles and contaminate the processing substrate.

  In the sputtering target of Comparative Example A3 in which the surface roughness of the erosion region and the surface roughness of the second non-erosion region were too large, abnormal discharge occurred 53 times in the second non-erosion region.

  In the sputtering target of Comparative Example A4 in which the surface roughness of the first non-erosion region is too small, the film attached to the first non-erosion region was peeled off by sputtering. is there.

  In the sputtering target of Comparative Example A5 where the surface roughness of the first non-erosion region was too large, abnormal discharge occurred 12 times. Moreover, collapse occurred on the target surface.

  In the sputtering target of Comparative Example A6 where the surface roughness of the erosion region was too large, abnormal discharge occurred 84 times in the erosion region.

  As described above, according to the AZO-based sputtering target of the embodiment according to the present invention, there is almost no abnormal discharge, cracking, and peeling of the attached film, and film formation by magnetron sputtering for a long time without deteriorating film formation performance. It was confirmed that it was possible.

(GZO-based sputtering target)
Next, for Examples B1 to B4 and Comparative Examples B1 to B6 in the GZO-based sputtering target, each surface roughness of the erosion region, the first non-erosion region, and the second non-erosion region, and the width of the second non-erosion region And the distance from the first non-erosion region to the edge of the sputtering target were varied as shown in Table 3.

The sputtering targets in GZO-based Examples B1 to B4 and Comparative Examples B1 to B6 were prepared as follows. That is, commercially available ZnO powder and Ga ₂ O ₃ powder each having an average particle size of 0.5 μm and a purity of 99.9% or more were prepared as raw material powders. These raw material powders were blended so that ZnO was 99.5% by mass and Ga ₂ O ₃ was 0.5% by mass. It was.

After drying the obtained mixed powder, it is filled into a rubber mold and subjected to cold isostatic pressing under a pressure of ² Ton / cm ² to produce a molded body. The molded body has a diameter of 180 mm and a thickness of 20 mm. It processed into the disk-shaped molded object which has a dimension, and obtained the disk-shaped molded object. The obtained disk-shaped molded body was heated at 1400 ° C. in the atmosphere to produce a sintered body having a theoretical density ratio of 95% or more. Further, the obtained sintered body was ground to prepare a GZO-based sputtering target having a diameter of 125 mm and a thickness of 10 mm. The composition of the target is 0.5% by mass for Ga ₂ O _{3 and} 99.5% by mass for ZnO by ICP analysis.

The adjustment method of the surface roughness of the sputtering target in each Example and Comparative Example is, for example, as follows. That is, with an abrasive (mainly # 46 in accordance with JIS rules) containing alumina (Al ₂ O ₃ ) as a blast grain, the blast injection pressure is 0.3 ± 0.05 MPa, and the blast time is 30 to 90 seconds. Blasting. The injection pressure and blasting time vary depending on the blasting device used.

  A mask made of a vinyl chloride plate is fixed to a portion of the sputtering target that is not blasted. Masking can also be performed with an adhesive tape, a metal mask, or the like. Blasting may cause abrasive particles to adhere to the target, which is removed by ultrasonic cleaning.

And the evaluation test which uses each sputtering target of these Examples B1-B4 and Comparative Examples B1-B6 for sputtering of the power density 10Wh / cm < ² > by a DC sputtering apparatus, the sputtering time 1 hour, and the integrated electric energy 10WHr / cm < ² >. went. Each sputtering target is confirmed in advance by X-ray transmission images after bonding to be free of bonding defects, cracks and cracks. Table 4 shows the number of occurrences of abnormal discharge during sputtering, the presence or absence of cracks in the target, and the presence or absence of peeling of the film attached by sputtering.

  In addition, the presence or absence of the generation | occurrence | production of a crack was confirmed visually after the target was ultrasonically cleaned. Further, the number of abnormal discharges was counted as the cumulative number of arcing during the sputtering.

  It was confirmed that the sputtering targets of Examples B1 to B3 were free from abnormal discharge, cracks, and peeling of the attached film, and could be formed by magnetron sputtering for a long time without deteriorating the film forming performance.

  In Example B4, the first non-erosion region is provided without being separated from the edge of the sputtering target. That is, the surface roughness of the edge portion of the sputtering target is large. Although no crack was seen from the appearance, two abnormal discharges occurred due to the large surface roughness up to the edge.

  In the sputtering target of Comparative Example B1 in which the width of the second non-erosion region was too small, abnormal discharge occurred three times when the processing time passed during sputtering. Further, since resputtering occurs, particles are generated, which may cause contamination of the sputtered film.

  In the sputtering target of Comparative Example B2 in which the width of the second non-erosion region is too large, since the film attached to the second non-erosion region is peeled off, the peeled material may become particles and contaminate the processing substrate.

  In the sputtering target of Comparative Example B3 in which the surface roughness of the erosion region and the surface roughness of the non-erosion region were too large, abnormal discharge occurred 57 times in the second non-erosion region.

  In the sputtering target of Comparative Example B4 in which the surface roughness of the first non-erosion region is too small, since the film attached to the first non-erosion region was peeled off by sputtering, there is a possibility that the peeled material becomes particles and contaminates the processing substrate. is there.

  In the sputtering target of Comparative Example B5 in which the surface roughness of the first non-erosion region was too large, abnormal discharge occurred 21 times. Moreover, collapse occurred on the target surface.

  In the sputtering target of Comparative Example B6 in which the surface roughness of the erosion region was too large, abnormal discharge occurred 98 times in the erosion region.

  As described above, according to the GZO-based sputtering target of the embodiment according to the present invention, there is almost no abnormal discharge, cracking, and peeling of the attached film, and film formation by magnetron sputtering for a long time without deteriorating film formation performance. It was confirmed that it was possible.

10 sputtering target 10a surface 10b rectangular hole 10c edge 20 erosion region 21 non-erosion region 21a first non-erosion region (rough surface region)
21b Second non-erosion region (smooth surface region)
21c Smooth edge region 100 Magnetron sputtering apparatus 101 Vacuum chamber 101a Gas inlet 101b Gas outlet 102 Processing substrate 103 Stage 104 Target holder 105 Magnet 106 External power source

Claims (2)

It was added 0.5～6.0Wt% of 0.1～3.0Wt% or Ga ₂ O ₃ and Al ₂ O ₃ to ZnO, there in AZO-based or GZO based oxide target used in the magnetron sputtering And
The surface is set to an erosion region to be sputtered with a surface roughness Ra of 1.0 μm or less and a non-erosion region to be not sputtered,
The non-erosion region is separated from the erosion region and has a surface roughness Ra of 3.0 μm to 6.0 μm, and a region between the first non-erosion region and the erosion region. A sputtering target having a surface roughness of Ra 1.0 μm or less and a second non-erosion region provided with a width of 5 to 15 mm around the erosion region.   The sputtering target according to claim 1, wherein the first non-erosion region is provided so as to be separated from an edge portion of the sputtering target.

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