CN109804099B

CN109804099B - Method for repairing backing plate for sputtering target, backing plate after repair, and sputtering target

Info

Publication number: CN109804099B
Application number: CN201780061583.0A
Authority: CN
Inventors: 大内康裕; 畠英雄; 中根靖夫
Original assignee: Kobelco Research Institute Inc
Current assignee: Kobelco Research Institute Inc
Priority date: 2016-12-28
Filing date: 2017-08-22
Publication date: 2021-05-07
Anticipated expiration: 2037-08-22
Also published as: JP6649245B2; WO2018123132A1; KR20190086010A; JP2018109202A; CN109804099A; TW201823491A; TWI660059B

Abstract

An embodiment of the invention is a method for repairing a back plate (20) comprising a copper base (22) with a defect part (24), wherein the method comprises the following steps: a step of polishing the surface of the defective portion (24); and a step of spraying and depositing repair particles containing copper particles and ceramic particles on the defect part (24) after the polishing step.

Description

Method for repairing backing plate for sputtering target, backing plate after repair, and sputtering target

Technical Field

The present invention relates to a method of repairing a backing plate used for a sputtering target and a backing plate repaired by the method.

Background

Fig. 2A is a sectional view of a general sputtering target 1 used in a film deposition apparatus. The sputtering target 1 includes a target base material 50 for forming a sputtered film, and a backing plate 10 for holding and cooling the target base material 50. The target base 50 is soldered (bonded) to a predetermined position on the back plate upper surface 10a with a solder such as indium. The backing plate 10 has a water passage 18 provided therein, and the water passage 18 is used for flowing cooling water for cooling the target base material 50 during use of the sputtering target 1.

The sputtering target 1 is placed on the mounting table 90 so that the lower surface 10b of the backing plate 10 contacts the mounting table 90 of the film deposition apparatus, and then is fixed to the mounting table 90 by bolts using bolt holes formed in the backing plate 10. At this time, a sealing material such as an O-ring is disposed between the mounting table 90 and the back plate lower surface 10b to seal the atmosphere in the film forming apparatus. Further, an O-ring or the like is disposed at a connection portion between the water passage 18 formed in the back plate and the water passage 98 formed in the mounting table 90 to prevent water leakage.

As is clear from fig. 2A, since the upper surface 10a of the backing plate 10 is wider than the bottom surface 50b of the target base 50, a part of the backing plate upper surface 10a is exposed around the target base 50. When the sputtering target 1 is used in the film forming apparatus, the target base material 50 sputtered around the target base material 50 is deposited (reattached) on the backing plate upper surface 10a, and the reattached film 40 is formed as shown in fig. 2B.

If the target substrate 50 is consumed like in fig. 2B, the target substrate 50 is peeled off from the backing sheet 10. Then, the re-adhesion film 40 attached to the back plate upper surface 10a is mechanically removed, and after a polishing process, a new target substrate 50 is fixed (fig. 2C). When the reattachment film 40 is removed, a small depression (defective portion 24) may occur on the back plate upper surface 10 a.

In the sputtering target 1 shown in fig. 2A to 2C, a backing plate 10 and a target base 50 are separately prepared and are joined by brazing. Sputtering targets of different types from these are also known.

For example, patent document 1 discloses a sputtering target in which a backing plate is deposited on the back surface of a target by a cold spray method.

Further, patent document 2 discloses a sputtering target that does not use a backing plate. The sputtering target of patent document 2 is formed by depositing a target layer on a base by a cold spray method.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-245635

Patent document 2: international publication No. 2008/081585

When the target base material 50 on the backing plate is replaced a plurality of times, the reattachment film 40 is removed every time of replacement, so the depth of the defective portion 24 is increased. As a result, if defective portion 24 reaches water channel 18 in the back plate, water leakage occurs from defective portion 24. Further, if the chipped portion 24 reaches the bolt hole of the backing plate 10, there is a possibility that a problem may occur when the sputtering target is bolt-fixed to the film forming apparatus.

In addition, in a process of attaching and detaching a sputtering target to and from a film forming apparatus, a back plate may be dented (a chipped portion) such as a scratch. If a defective portion is formed on a sealing surface where a sealing material such as an O-ring contacts, there is a possibility that leakage of cooling water or leakage of atmospheric gas in a film forming apparatus may occur.

If a back plate in which water leakage or atmospheric gas leakage is likely to occur is used, there is a possibility that serious problems such as failure of the film forming apparatus and deterioration of the quality of the sputtered film may occur. Therefore, such a back plate is discarded.

Since the back plate is very expensive, it is desirable to repair the defect for reuse. However, such a defect repair technique has not yet been established.

Disclosure of Invention

Accordingly, an object of an embodiment of the present invention is to provide a method of repairing a backing plate having a defective portion, a reusable repaired backing plate, and a sputtering target using the repaired backing plate.

In the embodiment 1 of the present invention,

a method for repairing a back plate having a base made of copper and having a defective portion, comprising the steps of:

a polishing step of polishing the surface of the defective portion;

a step of spraying and depositing particles for repair on the defect part after the polishing step,

the particles for repairing contain copper particles and ceramic particles.

Scheme 2 of an embodiment of the present invention, the method for repairing a back sheet according to scheme 1, wherein,

when the particles for repairing are sprayed, the pressure of working gas is more than 0.3MPa, and the gas temperature of the working gas is 200-700 ℃.

Scheme 3 of an embodiment of the present invention, the method for repairing a back sheet according to scheme 1 or 2, wherein,

the particles for repair contain more than 0 vol% and 60 vol% or less of ceramic particles.

The method for repairing a back sheet according to any one of claims 1 to 3, in accordance with embodiment 4 of the present invention,

the average particle size of the copper particles is 10-80 μm, and the average particle size of the ceramic powder is 0.5-30 μm.

The method for repairing a back sheet according to any one of claims 1 to 4, wherein in embodiment 5 of the present invention,

the ceramic particles contain at least one selected from the group consisting of alumina (aluminum oxide) particles, silica (silicon dioxide) particles, silicon carbide particles, zirconia (zirconium oxide) particles and titanium oxide (titanium oxide) particles.

The method for repairing a back sheet according to any one of claims 1 to 5, wherein in embodiment 6 of the present invention,

the polishing step includes a step of adjusting the surface roughness of the defective portion to Rz1.6 to 50.

Embodiment 7 of the present invention is a repaired back plate, characterized in that,

comprises a base made of copper and having a defective portion, and a repair member arranged inside the defective portion,

the repair member contains ceramic particles, has a hardness of Hv 70-150, and an average porosity of 5% or less.

Embodiment 8 of the present invention is the repaired back sheet according to embodiment 7, wherein,

the content of the ceramic particles in the repair member is higher than 0 vol% and 30 vol% or less.

Embodiment 9 of the present invention is the repaired back sheet according to embodiment 7 or 8, wherein,

the average particle diameter of the ceramic particles is 0.5 to 30 μm.

Embodiment 10 of the present invention is a sputtering target comprising:

a repaired back plate repaired by the repairing method according to any one of the schemes 1 to 6, or the repaired back plate according to any one of the schemes 7 to 9; and

and a target substrate fixed to the repaired backing plate.

According to the repairing method of the embodiment of the present invention, the back plate which is not usable due to abrasion or the like can be repaired to be reusable.

In the repaired backplate according to the embodiment of the present invention, the repair member is firmly fixed to the base of the backplate and has a sufficiently high strength, so that it can be reused as the backplate.

The sputtering target according to the embodiment of the present invention can reduce the cost of the sputtering target by using the repaired backing plate.

Drawings

Fig. 1A is a schematic sectional view for explaining a method of repairing a defective portion of a base of a back plate.

Fig. 1B is a schematic sectional view for explaining a method of repairing a defective portion of a base of a back plate.

Fig. 1C is a schematic sectional view for explaining a method of repairing a defective portion of a base of a back plate.

Fig. 1D is a schematic sectional view for explaining a method of repairing a defective portion of a base of a back plate.

Fig. 1E is a schematic sectional view for explaining a method of repairing a defective portion of the base of the back plate.

Fig. 2A is a schematic sectional view for explaining a sputtering target.

Fig. 2B is a schematic sectional view for explaining a used sputtering target.

Fig. 2C is a schematic sectional view for explaining a sputtering target including a reused backing plate.

Detailed Description

An embodiment of the present invention is a method for repairing a defective portion (defective portion) when the defective portion is dented due to scratches, abrasion, or the like on a copper base included in a back plate. In the repairing method according to the embodiment of the present invention, the particles for repairing are deposited on the defect portion by a so-called cold spray method in which the particles for repairing are sprayed at a temperature not higher than the melting point. Since the cold spray method does not heat the substrate, deformation of the substrate (for example, warpage of the substrate) accompanying thermal expansion can be avoided. Further, since the particles for repair contain not only copper particles but also ceramic particles harder than copper, the ceramic particles can be nailed to the surface of the defect portion to function as an anchor bolt. The ceramic particles can remove the copper oxide film formed on the surface of the defective portion. Therefore, when the particles for repair are sprayed and deposited on the defect portion, the adhesion force between the deposit (repair member) and the surface of the defect portion can be increased. In addition, the ceramic particles are taken into the interior of the repair member, and the hardness of the repair member is increased.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, terms indicating specific directions and positions (for example, "upper", "lower", "right", "left" and other terms including these terms) are used as necessary. These terms are used for the purpose of facilitating understanding of the present invention with reference to the drawings, and are not intended to limit the technical scope of the present invention. In addition, portions with the same reference numerals shown in the drawings denote the same portions or members.

< embodiment 1 >

The method of repairing the back plate will be described with reference to fig. 1A to 1E.

1. Peeling of the target substrate 50 and removal of the reattachment film 40

Fig. 1A is a partially enlarged sectional view of a used sputtering target 1 in the vicinity of a defect portion 24. The defect 24 is recessed from the surface 22x (indicated by the dashed line) of the substrate 22 prior to use.

The back plate 10 comprises a substrate 22 made of copper. On the base 22, the consumed target substrate 50 is fixed via a brazing material 55. The defective portion 24 is formed around the target base material 50 on the surface of the base 22, and the back plate 10 is reused. The surface of the defective portion 24 is covered with a reattachment film 40.

Before the repair of the backing sheet 10, first, the target substrate 50 is peeled off. The target base 50 is removed in a state where the base 22 is heated to melt the brazing material 55. Thereafter, the reattachment film 40 on the surface of the defective portion 24 is mechanically removed by cutting, grinding, polishing, or the like (fig. 1B).

2. Grinding of the surface of the defect 24

After the reattachment film 40 is removed, the surface of the defective portion 24 is polished. Since the base 22 is made of copper which is easily oxidized, the surface of the defect portion 24 is usually covered with an oxide film. In the subsequent step, the particles for repair are attached to the defect portion 24 by the cold spray method, but if the surface of the defect portion 24 is covered with an oxide film, the particles for repair are difficult to attach. Therefore, as a pretreatment for cold spray, the surface of the defective portion 24 is polished to remove the oxide film. As the polishing method, mechanical polishing (a disc grinder, sandpaper, or the like) or chemical polishing can be used.

When the surface of the defective portion 24 is polished with a surface roughness rz1.6 to 50, the adhesion of the particles for repair is improved by the anchor bolt effect, which is preferable. If the surface roughness is too coarse, pores tend to remain at the interface between the surface of the defect portion 24 and the particles for repair.

3. Repair of defective portion 24 (Cold spray method)

After polishing the surface of the defective portion 24, particles for repair are sprayed to the defective portion 24. Thereby, particles for repair are deposited on the defective portion 24, and the repair member 30 is formed. When the prosthetic member 30 is deposited in the defect portion 24, it is preferably deposited so as to be raised from the surface 22a of the base 22 as shown in fig. 1C. This enables the entire defective portion 24 to be reliably repaired.

As the particles for repair, particles containing copper (particularly, pure copper having a purity of 99.9% or more) of the same material as the base 22 and ceramic particles are used. By containing the ceramic particles, the adhesion between the repair member 30 and the defective portion 24 can be improved. The reason is assumed to be as follows.

When the particles for repair are sprayed to the defective portion 24, the ceramic particles included in the particles for repair collide with the surface of the defective portion 24. At this time, it is considered that the ceramic particles having a higher hardness than copper are stuck into the surface of the defect portion 24 and act as anchors. It is also considered that the copper oxide formed after polishing can be peeled off by the ceramic particles. Therefore, when the copper particles contained in the particles for repair are attached to the surface of the defective portion 24 to form the repair member 30, the repair member 30 can be firmly adhered to the defective portion 24.

Since the particles for repair contain copper particles and ceramic particles, the repair member 30 is a mixed repair member 30 containing copper particles and ceramic particles. By containing the ceramic particles, the repaired member 30 having a higher hardness can be formed than a repaired member formed only of copper particles.

The particles for repair may contain particles other than copper particles and ceramic particles.

The average particle diameter of the copper particles used for the particles for repair is preferably 10 to 80 μm. If the average particle diameter is too small, the mass of the particles becomes small, the kinetic energy becomes insufficient, and the deposition efficiency (deposition yield) may decrease. If the average particle size is too large, pores are likely to be generated in the interior of the deposited repair member 30. When the average particle diameter of the copper particles is 10 to 80 μm, the appropriate deposition efficiency can be achieved in combination with the reduction of the porosity in the repair member 30. The average particle diameter of the copper particles is more preferably 50 μm or less.

As the copper particles, atomized powder, electrolytic powder, or the like can be used.

The average particle diameter of the ceramic particles used for the particles for repair is preferably 0.5 to 30 μm. If the average particle diameter is too small, the mass of the particles becomes small, the kinetic energy becomes insufficient, and the oxide film removing effect and the anchoring effect are hardly exhibited. If the average particle size is too large, the kinetic energy becomes too large, and there is a possibility that cracks may occur when the particles collide with the deposited repair member 30, and the base 22 and the repair member 30 may be peeled off.

The particles for repair preferably contain ceramic particles in an amount of more than 0 vol% and 60 vol% or less. Particularly, it is preferably contained in an amount of 5% by volume or more and 50% by volume or less.

If the content of the ceramic particles is large, the hardness of the repair member 30 tends to be too high, and cracks tend to be easily generated. In addition, when the content of the alumina particles is large, the content of the copper particles is relatively small. Since the copper particles are plastically deformed by the cold spray method and adhere to the surface of the defective portion 24, the adhesion of the repair member 30 is easily reduced when the content of the copper particles is small. That is, when the content of the ceramic particles is large, the adhesion of the repair member 30 is reduced, and the repair member is easily peeled from the defective portion 24. If the content of the ceramic particles is 60 vol% or less, the repaired member 30 having appropriate hardness can be obtained, and the detachment of the repaired member 30 can be suppressed. The content of the ceramic particles is more preferably 25 vol%.

The content of the ceramic particles in the repair member 30 is about half of the content (volume fraction) of the ceramic particles in the particles for repair. This is because the specific gravity of ceramic (e.g., alumina) is smaller than that of copper, and therefore the proportion of ceramic particles blown off by the high-speed gas flow is high at the time of cold spraying, and the deposition yield of ceramic particles is lower than that of copper particles. Therefore, when the repair member 30 is formed using the particles for repair containing the ceramic particles in an amount of more than 0 vol% and 60 vol% or less, the content of the ceramic particles in the repair member 30 is assumed to be more than 0 vol% and about 30 vol% or less. Note that, since the deposition yield varies depending on the type of ceramic particles used, the content of the ceramic particles in the repair member 30 is not limited to 30 vol% or less even if the content of the ceramic particles in the repair particles is 60 vol% or less.

As the ceramic particles, alumina (aluminum oxide) particles, silica (silicon dioxide) particles, silicon carbide particles, zirconia (zirconium oxide) particles, titanium oxide (titanium oxide) particles, and the like can be used.

The average particle diameters of the copper particles and the ceramic particles contained in the particles for repair are measured by a particle size distribution measuring instrument, and the particle diameter at 50 wt% in terms of cumulative particle size distribution is defined as the "average particle diameter". As the particle size distribution measuring device, for example, a laser diffraction type particle size distribution measuring device (e.g., Blue Raytrac manufactured by マイクロトラックベル) can be used.

For the injection of the particles for repair, a working gas is used. By transporting the particles for repair with the high-speed working gas, the particles for repair collide with the defect portion 24 and are deposited. As the working gas, an atmospheric gas, an inert gas (nitrogen gas and helium gas), or the like can be used.

The pressure of the working gas is preferably 0.3 to 1 MPa. If the gas pressure is too low, the particles for repair cannot be sufficiently accelerated, and the porosity of the repair member 30 tends to increase. The higher the gas pressure is, the lower the porosity of the repair member 30 is, and a dense repair member 30 can be obtained, which is preferable. On the other hand, if the gas pressure becomes high, it is necessary to use expensive devices and equipment that can withstand high pressure for the devices and peripheral equipment used for cold spraying. Therefore, the repair cost of the back plate becomes high. When the gas pressure is 0.3 to 1MPa, the cost can be suppressed and a dense repair member 30 having a low porosity can be formed.

In the embodiment of the present invention, since the repair member 30 is formed by the cold spray method, the gas temperature of the working gas is lower than the melting point of the particles for repair. That is, the particles for repair collide with the surface of the defective portion 24 in a non-melted state and are accumulated thereon. However, if the particles for repair are at room temperature, they are difficult to deposit, and it is difficult to form a dense repair member 30. Therefore, the particles for repair are preferably heated to some extent. Specifically, when the temperature of the working gas for transporting the particles for repair is, for example, 200 to 700 ℃, the dense repair member 30 having low porosity can be formed. The porosity of the repair member 30 can be reduced as the temperature of the working gas is higher, but if the temperature is too high, the copper base 22 may be excessively heated and softened.

4. Planarization of repair member 30

As shown in fig. 1C, the repairing member 30 is stacked in a state of being raised with respect to the surface 22a of the base 22, and thus, the raised portion (excess thickness portion) is removed by a mechanical removal method such as cutting, grinding, or polishing (fig. 1D and 1E). For example, for the excess thickness portion of the repair member 30, most of it is first removed by cutting (fig. 1D), and thereafter, it is polished flush with the surface 22a of the substrate 22 (fig. 1E).

Next, the characteristics of the repaired backing plate 20 shown in fig. 1E, in which the member 30 is repaired, will be described.

Hardness of the repair member 30: hv 70-150

The backing plate 20 is reused by replacing the target substrate. In recycling, after the spent target base material is peeled off, and before a new target base material is welded, the surface 22a of the base 22 of the backing plate 20 is polished to be clean. In this case, if the hardness of the repair member 30 is Hv70 to 150, only the repair member 30 can suppress abnormal wear. If the hardness is higher than Hv150, ductility is insufficient, and therefore the repair member 30 easily penetrates into cracks and easily peels off from the defective portion 24 of the base 22.

Average porosity of the repair member 30: less than 5%

The backing plate 20 is mounted on a high vacuum apparatus such as a film forming apparatus (sputtering apparatus). Therefore, it is important that the backing plate 20 be clean and that no gas be generated from the backing plate 20. If the porosity of the repair member 30 is high (a large amount of pores are contained), impurities are accumulated in the pores, and therefore the impurities may diffuse into the apparatus during film formation. Further, since the inner surface in the gas hole can adsorb gas, if the porosity is high, the amount of adsorbed gas may increase. The gas in the gas hole is released into the apparatus during film formation. Impurities and gases in the gas holes may adversely affect the quality of the sputtered film.

Since the porosity of the repair member 30 is as low as 5% or less, the quality of the sputtered film can be suppressed from deteriorating even when the repaired backing plate 20 is used.

The porosity can be measured by observing the cross section of the repair member 30 with an SEM (scanning electron microscope). Specifically, first, the area Sp of the pores included in the field of view of 500 μm × 500 μm is determined from an SEM image of the cross section of the repair member 30 taken at a magnification of 100 times. By the area Sp (μm) of the pores²) Divided by the area of the field of view 500X 500(μm)²) And obtaining the porosity. Namely, the porosity (%) is Sp/(500 × 500) × 100 (%).

The SEM images each measured 1 field at 5 different positions of the cross section of the repair member 30. The average porosity obtained in the total of 5 fields is referred to as "average porosity".

Content of ceramic particles in the repair member 30: above 0% and below 30% by volume

In the repaired backing plate 20, the repair member 30 contains copper and ceramic particles. In addition, copper particles contained in the particles for repair are adhered by plastic deformation at the time of cold spraying, and therefore the particle state is often not maintained. On the other hand, most of the ceramic particles contained in the particles for repair are present in the repair member 30 in a state of maintaining the particle shape.

The greater the content of the ceramic particles, the higher the hardness of the repair member 30. When the content of the ceramic particles in the repaired member 30 is higher than 0 vol% and 30 vol% or less, the repaired member 30 having an appropriate hardness, for example, Hv70 to 150 can be obtained. The content of the ceramic particles is more preferably 25 vol%.

The SEM images each measured 1 field at 5 different positions of the cross section of the repair member 30. The average porosity obtained in the total of 5 visual fields was determined to obtain "average porosity".

Average particle size of ceramic particles: 0.5 to 30 μm

The average particle diameter of the ceramic particles is substantially equal to the average particle diameter of the particles for repair when contained in the particles. As described above, the average particle diameter of the ceramic particles contained in the particles for repair is preferably 0.5 to 30 μm. Therefore, the average particle diameter of the ceramic particles in the repair member 30 is also preferably 0.5 to 30 μm.

The average particle diameter of the ceramic particles in the repair member 30 can be measured by observing the cross section of the repair member 30 with an SEM. Specifically, in an SEM image of a cross section of the repair member 30 taken at 400 × magnification, the particle diameter of each particle was measured for all ceramic particles contained in a 175 × 225 μm field of view. The particle size is defined as the maximum size of particles having a shape other than a circle. 1 field was measured at each of 5 different sites, and the average particle diameter was determined using data of particle diameters measured in 5 fields in total.

Since the repaired backing plate 20 shown in fig. 1E has the damaged portion 24 repaired by the repair member 30, the repaired backing plate can be reused as a sputtering target without causing any trouble due to the damaged portion 24, such as water leakage or gas leakage.

Example 1

1. Preparation of test piece

25 base materials were prepared to simulate a back plate having a defective portion, and the base materials were repaired under different conditions to prepare test pieces.

A copper plate having a length of 100mm, a width of 100mm and a thickness of 10mm was prepared, and a V-shaped groove having a depth of 5mm, a width of 10mm and a length of 100mm was formed on the upper surface of the copper plate by end milling to obtain a substrate. The V-shaped groove was formed such that the longitudinal direction of the V-shaped groove was parallel to 1 side of the pure copper plate.

The inner surface of the V-groove of the substrate is processed to a predetermined surface roughness by a disc grinder or sandpaper. The surface roughness of each test piece is shown in table 1.

Thereafter, the interior of the V-shaped groove was sprayed with particles for repair using a DYMET423 type cold spray apparatus manufactured by OCPS. The particles for repair are prepared by mixing copper particles and alumina particles as ceramic particles. Table 1 shows the type (electrolytic powder or atomized powder) and the average particle size of the copper particles, and the content and the average particle size of the ceramic particles, as conditions of the particles for repair used in each sample.

The conditions (gas pressure and gas temperature) of the cold spraying are shown in Table 1.

In tables 1 to 2, underlined numerical values indicate ranges that deviate from the ranges of the embodiments of the present invention or preferred ranges of the embodiments of the present invention.

[ Table 1]

The repairing particles sprayed to the V-shaped groove form a repairing member. The repairing member is buried in the V-shaped groove, and particles for repairing are further sprayed until the repairing member rises from the upper surface of the test piece. Thereafter, the swelling portion (excess thickness portion) of the repaired member was removed by a disc grinder and a sand paper, and the surface of the repaired member was processed into a flat surface.

The samples thus obtained (examples 1 to 25 and comparative examples 1 to 8) were evaluated as follows.

Average particle size of ceramic particles, content (volume fraction) of ceramic particles, and porosity of the repair member:

the test piece was cut out in a square shape with a side of 20mm in a plan view. The test piece had 4 cross sections elongated in a direction perpendicular to the upper surface of the test piece (thickness direction of the test piece). 2 of the cross sections are parallel to the extending direction of the V-shaped groove and are opposite to each other through the V-shaped groove. The remaining 2 cross sections were perpendicular to the extending direction of the V-groove, and the interface between the repair member and the base material was observed from these cross sections. The latter cross section (i.e., the cross section including the repair member and the interface with the base material) was mirror-polished and observed by SEM. SEM images of 5 visual fields were taken for each test piece by 400-magnification observation, and the particle size of the ceramic, the content of the ceramic, and the porosity of the repair member were determined.

Particle size of ceramic:

in the repairing member in the SEM image, a range of 175. mu. m.times.225. mu.m was defined, and the particle size of the ceramic in this range was measured. In each field, the length of all the ceramic particles in the horizontal direction (direction parallel to the upper surface of the sample piece) was measured, and the average value of the measured lengths was determined based on the total number of particles of the ceramic. Then, the 5 "average values of the measured lengths" obtained for the 5 fields of view were averaged to obtain "the particle size of the ceramic" of the repair member.

The measurement results of the ceramic particle diameter are shown in table 2.

Content of ceramic:

in the repairing member in SEM image, 175 μm × 225 μm (39375 μm) is specified²) The area of the ceramic particles that can be confirmed in this range is determined. The area of the ceramic was divided by the area of the range (39375 μm)²) The value of (c) is multiplied by 100 to obtain "ceramic content" of the repaired component.

The measurement results of the content of the ceramic are shown in table 2.

Porosity of repaired part

In the repairing member in SEM image, 175 μm × 225 μm (39375 μm) is specified²) The area of the pores that can be confirmed in this range was determined. The area of the pores was divided by the area of the range (39375 μm)²) The value of (d) is multiplied by 100 to obtain "porosity of the repair member".

The measurement results of the porosity are shown in table 2.

Hardness measurement of repaired parts

Using a test piece used for measurement of porosity of a repair member, the porosity was measured in accordance with JIS Z2244: 2009, the hardness of the repair member was measured. After mirror polishing of a cross section including the repaired member (coating portion) and the interface with the base material, the portion of the repaired member (the vicinity of the center of the repaired member) in the cross section was measured by pressing a indenter with a load of 1 kg. The measurement results are shown in table 2.

Peeling test and crack test

The strength of the bonding force between the repair member and the base material and the crack difficulty of the repair member were examined.

The excess thickness portion of the mending member was removed by a disc grinder to make the upper surface of the sample piece flat. The upper surface of the repair member, which was flat, was sequentially polished with sandpaper having abrasive grains of #150, #300, and # 600. A punch made of steel having a tip diameter of 3mm was vertically pressed at 400kgf against the upper surface (polished surface) of the polished repair member. The presence or absence of separation and cracking was confirmed by visual observation of a range of a radius of 20mm, centering on the position where the punch was pressed (punch position). In the test, the punches were pressed at different 10 points. Each punch position is shifted by 40mm or more from the other punch positions so that the observation ranges do not overlap. In the 10-point observation range, the repaired member was found to be defective (NG) when the repaired member was peeled from the base material at 1 point or more, or when the repaired member was cracked. The results of the observation at 10 were that peeling and cracking did not occur in all the regions and that the results were "OK" and are shown in Table 2.

Stacking yield

The stacking yield (%) was calculated as (weight increase by repair)/(weight of particles for repair used) × 100. The "weight gain by repair" is obtained by subtracting the weight of the base material before repair from the weight of the base material after repair.

The results of calculation of the stacking yield are shown in Table 2.

[ Table 2]

In examples 1 to 25, since the repair was performed by appropriately controlling the conditions of the repair method (particularly, the average particle size of the copper particles, the content of the ceramic particles, the pressure of the cold spray and the gas temperature), the hardness and the porosity of the coating portion of the obtained repaired back sheet satisfy the scope of the present invention.

Examples 1 to 21 are particularly preferable examples, and all the preferable conditions (specifically, the average particle size of the copper particles, the content and the average particle size of the ceramic particles, the surface roughness of the defect portion of the repaired portion, and the gas pressure and the gas temperature of the cold spray) in the repairing method according to the embodiment of the present invention are satisfied. Therefore, the coating portions obtained in examples 1 to 21 were suitable in hardness and porosity, and were free from peeling and cracking. Therefore, it is understood that the excellent repair can be performed by the repair methods of examples 1 to 21. In addition, in examples 1 to 21, the deposition yield was as high as 40% or more, and the repair time was shortened.

The coating portions obtained in examples 22 to 24 were inferior to those obtained in examples 1 to 21 in peeling and crack generation. However, in examples 22 to 24, "hardness" and "porosity" of the coating portion, which are essential features in the embodiment of the present invention, satisfy the range of the embodiment of the present invention, and therefore, can be used for actual repair. Examples 22 to 24 are described in detail.

In example 22, the particle size of the ceramic particles contained in the particles for repair was larger than the preferable particle size in the embodiment of the present invention. Therefore, the ceramic particles contained in the formed coating portion had a large particle size, and peeling was confirmed in a peeling/cracking test.

In example 23, since the surface roughness of the defect portion was smaller than the preferable surface roughness of the embodiment of the present invention (i.e., the surface was smooth), the anchoring effect was not obtained, and peeling was confirmed in the peeling/cracking test.

In example 24, since the surface roughness of the defective portion was larger than the preferable surface roughness (i.e., surface roughness) of the embodiment of the present invention, a gap was left between the defective portion and the coating portion, and peeling was confirmed in the peeling/cracking test.

In example 25, the physical properties (hardness, porosity, and results of peeling/cracking test) of the obtained coating portion were excellent as in examples 1 to 21. However, since the average particle diameter of the copper particles in the particles for repair is small, the deposition yield is as low as less than 40%. Therefore, the time taken for repair is long.

On the other hand, comparative examples 1 to 8 are comparative examples in which the hardness and/or porosity of the coating portion does not satisfy the range of the embodiment of the present invention.

In comparative example 1, since the gas temperature of the cold spray was high, the hardness of the coating portion was low.

In comparative example 2, the content of the ceramic particles in the particles for repair was large, so that the content of the ceramic particles in the coating portion was large, and the hardness of the coating portion was high. Further, since the gas temperature of the cold spraying is low, the porosity of the coating portion is high. Since the coating portion had hard hardness and large porosity, cracks and separation were observed in the separation/crack test.

In comparative example 3, the average particle diameter of the copper particles contained in the particles for repair was large, and therefore the porosity of the coating portion was large. In addition, since the porosity is large, peeling occurs.

In comparative example 4, since the gas pressure of the cold spraying was low, the porosity of the coating portion was large. In addition, since the porosity was large, peeling was confirmed in the peeling/cracking test.

In comparative example 5, since the gas temperature of the cold spray was low, the porosity of the coating portion was large. In addition, since the porosity was large, peeling was confirmed in the peeling/cracking test.

In comparative example 6, since the particles for repair do not contain ceramic particles, the ceramic particles are not contained in the coating portion, and as a result, the hardness of the coating portion is lowered. Further, since the particles for repair do not contain ceramic particles, the anchoring effect from the ceramic particles is not obtained, and peeling is confirmed in the peeling/cracking test.

In comparative example 7, the content of the ceramic particles contained in the particles for repair was large, and therefore the content of the ceramic particles contained in the coating portion was large. As a result, the hardness of the coating portion was hardened, and cracks were observed in the peel/crack test.

In comparative example 8, the content of the ceramic particles in the coating portion was increased because the content of the ceramic particles in the particles for repair was increased. Therefore, the hardness of the coating portion becomes hard, and cracks are observed in the peeling/cracking test.

In the examples and comparative examples, the content of the ceramic particles in the coating portion was about half of the content of the ceramic particles in the particles for repair. This is because the specific gravity of ceramic (alumina) is smaller than that of copper, and therefore the proportion of ceramic particles blown away by the high-speed gas flow during cold spraying is high, and the deposition yield of ceramic particles is lower than that of copper particles.

This application is accompanied by the claims of priority based on 2016-. Japanese patent application No. 2016 & 256356 is incorporated herein by reference.

Description of the symbols

1 sputtering target

10 backboard

18 waterway

20 repaired backboard

22 base

24 defective part

30 repair member

40 reattachment film

50 target base material

55 brazing filler metal

Claims

1. A method for repairing a back plate including a base made of copper having a defective portion, the method comprising:

a polishing step of polishing the surface of the defective portion; and

the particles for repairing contain copper particles and ceramic particles.

2. The method for repairing a back plate according to claim 1, wherein a gas pressure of a working gas is 0.3MPa or more and a gas temperature of the working gas is 200 ℃ to 700 ℃ at the time of spraying the particles for repairing.

3. The method of repairing a back sheet according to claim 1 or 2, wherein the particles for repair contain more than 0 vol% and 60 vol% or less of ceramic particles.

4. The method for repairing a back sheet according to claim 1 or 2, wherein the average particle size of the copper particles is 10 to 80 μm, and the average particle size of the ceramic particles is 0.5 to 30 μm.

5. The method for repairing a back sheet according to claim 1 or 2, wherein the ceramic particles contain at least one selected from the group consisting of alumina particles, silica particles, silicon carbide particles, zirconia particles and titania particles.

6. The method for repairing a back plate according to claim 1 or 2, wherein the polishing step includes a step of adjusting the surface roughness of the defect portion to rz1.6 to 50.

7. A backboard after repair is characterized in that,

comprises a copper base having a defective portion and a repair member disposed in the defective portion,

8. The repaired backplate of claim 7, wherein the ceramic particles in the repair member are present in an amount greater than 0 vol% and less than 30 vol%.

9. The repaired back sheet according to claim 7 or 8, wherein the ceramic particles have an average particle diameter of 0.5 to 30 μm.

10. A sputtering target, comprising:

a repaired back plate repaired by the repair method according to claim 1 or 2, or the repaired back plate according to claim 7 or 8; and

and a target substrate fixed to the repaired backing plate.