bonded body

Abstract

The present application provides a ceramic plate and MMC plate joint body with high joint strength. The joint body comprises: a ceramic plate; an MMC plate disposed opposite one side of the ceramic plate and composed of a metal matrix composite (MMC) containing (i) Si, C and Ti, or (ii) Al, Si and C; and a joint layer disposed between the ceramic plate and the MMC plate, joining the ceramic plate and the MMC plate, and containing Al as a main component. The MMC plate has an Al-rich layer with Al distributed at a higher concentration than other parts of the MMC plate, and the depth D of the Al-rich layer is 40 μm or more. Al The Al-rich layer has a depth D of 40 μm or more. Al ​

Description

Technical Field

[0001] This invention relates to a joint. Background Technology

[0002] Circuit formation in semiconductor device manufacturing is typically performed using plasma etching. Plasma etching is achieved by introducing an inert gas into a vacuum chamber within a plasma etching apparatus to create plasma. An electrostatic chuck assembly, which serves as a base for holding the wafer to be etched, is installed within the plasma etching apparatus. A typical electrostatic chuck assembly includes an electrode-embedded ceramic plate that functions as an electrostatic chuck, and a cooling plate that supports the bottom surface of the electrode-embedded ceramic plate. The wafer is electrostatically attracted to the electrode-embedded ceramic plate, thereby performing plasma etching while it is fixed to the electrostatic chuck assembly. The cooling plate, located on the bottom surface of the electrode-embedded ceramic plate, dissipates heat generated on the wafer during plasma etching. The electrode-embedded ceramic plate typically has the following configuration: internal electrodes such as electrostatic chuck (ESC) electrodes, RF electrodes, and heater electrodes are embedded within a ceramic substrate made of materials with excellent heat resistance and corrosion resistance, such as alumina or aluminum nitride.

[0003] As an example of an electrostatic chuck assembly, Patent Document 1 (Japanese Patent Application Publication No. 2009-141204) discloses a substrate holder, which is formed by bonding a first substrate made of a first ceramic sintered body and a second substrate made of a second ceramic sintered body using a bonding film containing an Al metal. This document discloses that the bonding film containing an Al metal is sandwiched between the first and second substrates, and while heating the metal, hot-pressing is performed at a pressure of 4 to 20 MPa, thereby bonding the first and second substrates using the bonding film. The Al-containing metal is preferably an Al alloy containing Mg in the range of 0.5 to 5% by weight.

[0004] However, in recent years, metal matrix composites (MMCs) have attracted much attention. Metal matrix composites are materials obtained by combining a metal matrix composed of metals such as Al and Si with ceramic reinforcing materials such as SiC and TiC. They are known to have advantages such as lightweight, high rigidity, high thermal conductivity, and low thermal expansion. Methods for bonding metal matrix composites (MMCs) and ceramic materials have been proposed. Patent Document 2 (Japanese Patent No. 4373538) discloses a joint in which an MMC containing an aluminum alloy as a matrix and a ceramic material are bonded together using a solder composed of an Al alloy containing Mg.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-141204

[0008] Patent Document 2: Japanese Patent No. 4373538

[0009] Patent Document 3: Japanese Patent Application Publication No. 2006-196864 Summary of the Invention

[0010] As a cooling plate for electrostatic chuck assemblies, MMC plates are preferred due to their advantages such as high thermal conductivity and low thermal expansion. Therefore, it is necessary to improve the bonding strength between the MMC plate and the ceramic plate.

[0011] The inventors of this invention have recently discovered that by providing a specified bonding layer between an MMC board and a ceramic board, and by having an Al-rich layer in the MMC board from the bonding interface between the bonding layer and the MMC board to a specified depth (thickness), it is possible to provide a joint between a ceramic board and an MMC board with high bonding strength.

[0012] Therefore, the object of the present invention is to provide a joint between a ceramic plate and an MMC plate with high bonding strength.

[0013] According to the present invention, the following solution is provided.

[0014] [Option 1]

[0015] A joint comprising:

[0016] Ceramic slab;

[0017] An MMC plate, configured to face one side of the ceramic plate, and composed of a metal matrix composite (MMC) comprising (i) Si, C, and Ti, or (ii) Al, Si, and C; and

[0018] A bonding layer is disposed between the ceramic plate and the MMC plate to bond the ceramic plate and the MMC plate, and the bonding layer contains Al as the main component.

[0019] The MMC board extends from the bonding interface between the bonding layer and the MMC board to a specified depth D. Al The Al-enriched layer has an Al concentration distributed at a higher level than other parts of the MMC plate, and the depth D of the Al-enriched layer is... Al It is above 40μm.

[0020] [Option 2]

[0021] According to the joint described in Scheme 1, wherein...

[0022] The metal matrix composite (MMC) contains Si, C and Ti, as well as Al, or Al and N.

[0023] [Option 3]

[0024] According to the joint described in scheme 1 or 2, wherein,

[0025] The metal matrix composite (MMC) contains Al, Si, and C.

[0026] [Option 4]

[0027] According to any one of Schemes 1 to 3, the joint wherein,

[0028] The bonding layer also contains Si as a secondary component.

[0029] [Option 5]

[0030] According to any one of Schemes 1 to 4, the joint wherein,

[0031] The bonding layer also contains Mg as a secondary component.

[0032] [Option 6]

[0033] According to the joint described in Scheme 5, wherein...

[0034] The MMC board extends from the bonding interface between the bonding layer and the MMC board to a specified depth D. Mg A Mg diffusion layer derived from the Mg diffusion of the bonding layer.

[0035] [Option 7]

[0036] According to the joint described in Scheme 6, wherein...

[0037] The depth D of the Al enrichment layer Al The depth D of the Mg diffusion layer is greater than that of the Mg diffusion layer. Mg That is, satisfying D Al >D Mg .

[0038] [Option 8]

[0039] According to any one of Schemes 1 to 7, the joint wherein,

[0040] The ceramic plate comprises aluminum oxide and / or aluminum nitride and has internal electrodes embedded therein.

[0041] [Option 9]

[0042] According to any one of Schemes 1 to 8, the joint wherein,

[0043] The ceramic plate, the bonding layer, and the MMC plate are joined by thermoforming.

[0044] [Option 10]

[0045] According to any one of schemes 1 to 9, the joint wherein,

[0046] The surface of the MMC plate on the interface side has an arithmetic mean roughness Ra of 0.01 to 1.0 μm.

[0047] [Option 11]

[0048] The joint according to any one of schemes 1 to 10, wherein,

[0049] The joint strength exhibited above 200 MPa in the 4-point bending test. Attached Figure Description

[0050] Figure 1 This is a simplified cross-sectional view showing an example of the joint involved in the present invention.

[0051] Figure 2 This is a simplified cross-sectional view showing another example of the joint involved in the present invention.

[0052] Figure 3A The image shows a SEM image (Compo image) of a cross section of the joint including the ceramic plate 12, the joint interface 20 and the joint layer 16 in Example 7, and Si, C and Ti mapping images of the corresponding regions.

[0053] Figure 3B The SEM image (Compo image) of the cross section of the joint including the ceramic plate 12, the joint interface 20 and the joint layer 16 in Example 7 is shown, along with the O, Mg and Al mapping images of the corresponding regions.

[0054] Figure 4A The SEM image (Compo image) of the cross section of the joint including the bonding layer 16, the bonding interface 22 and the MMC plate 14 in Example 7 is shown, along with Si, C and Ti mapping images of the corresponding regions.

[0055] Figure 4B The SEM image (Compo image) of the cross section of the joint body in Example 7, including the joint layer 16, the joint interface 22 and the MMC plate 14, and the corresponding O, Mg and Al mapping images of the region are shown.

[0056] Figure 5A The SEM image (Compo image) of the cross section of the joint including the bonding layer 16, the bonding interface 22 and the MMC plate 14 in Example 7 is shown, along with a reduced-concentration scale version of the Si, C and Ti mapping images of the corresponding regions.

[0057] Figure 5B The SEM image (Compo image) of the cross section of the joint including the bonding layer 16, the bonding interface 22 and the MMC plate 14 in Example 7 is shown, along with a reduced concentration scale version of the O, Mg and Al mapping images of the corresponding regions. Detailed Implementation

[0058] joint

[0059] Figure 1 An example of the joint involved in the present invention is shown in the figure. Figure 1 The shown bonding assembly 10 includes a ceramic plate 12, an MMC plate 14, and a bonding layer 16. Preferably, the ceramic plate 12 comprises alumina and / or aluminum nitride and has an internal electrode 18 embedded therein. The MMC plate 14 is a plate made of metal matrix composite (MMC) and is positioned opposite one side of the ceramic plate 12. The metal matrix composite (MMC) comprises (i) Si, C, and Ti, or (ii) Al, Si, and C. The bonding layer 16 is a layer that bonds the ceramic plate 12 and the MMC plate 14, and is disposed between the ceramic plate 12 and the MMC plate 14. The bonding layer 16 comprises Al as the main component. Figure 2 More specifically, the MMC board 14 extends from the bonding interface 22 between the bonding layer 16 and the MMC board 14 to a specified depth D. Al An Al-enriched layer 26 has Al distributed at a higher concentration than other parts of MMC plate 14. The depth D of the Al-enriched layer 26 is... Al The thickness is 40 μm or more. By providing a predetermined bonding layer 16 between the MMC plate 14 and the ceramic plate 12, and by having an Al-rich layer 26 from the bonding interface 22 between the bonding layer 16 and the MMC plate 14 to a predetermined depth (thickness), a joint 10 with high bonding strength between the ceramic plate 12 and the MMC plate 14 can be provided. That is, by not only using the predetermined bonding layer 16, but also providing the Al-rich layer 26, high bonding strength can be achieved between the MMC plate 14 and the ceramic plate 12.

[0060] The ceramic plate 12 is a plate-shaped component containing a ceramic sintered body, and can have the same configuration as ceramic plates used in known ceramic substrates (e.g., electrostatic chuck assemblies, ceramic heaters, etc.). Typically, an internal electrode 18 is embedded in the ceramic plate 12. The ceramic sintered body constituting the main part of the ceramic plate 12 (i.e., the ceramic matrix), excluding the internal electrode 18, preferably contains alumina and / or aluminum nitride from the viewpoints of excellent thermal conductivity, high electrical insulation, and thermal expansion characteristics close to those of silicon. In addition to alumina and / or aluminum nitride, the ceramic sintered body constituting the ceramic plate 12 may also contain additives such as MgO. In this case, the content of alumina and / or aluminum nitride in the ceramic sintered body constituting the ceramic plate 12 is typically 50 to 100% by mass, with the balance being additives such as MgO. The thickness of the ceramic plate 12 can be the thickness of a typical ceramic plate, without particular limitation, and can typically be 2 to 10 mm, more typically 2 to 5 mm.

[0061] Examples of internal electrodes 18 implanted in the ceramic plate 12 include: ESC electrodes, heater electrodes, and RF electrodes. Two types of internal electrodes 18 can be provided within the ceramic plate 12. An ESC electrode is short for Electrostatic Chuck (ESC) electrode, also known as an electrostatic electrode. The ESC electrode is preferably a thin, circular electrode with a diameter slightly smaller than the ceramic plate 12; for example, it can be a mesh-like electrode obtained by weaving fine metal wires into a mesh and forming it into a sheet. The ESC electrode can be used as a plasma electrode. That is, by applying a high frequency to the ESC electrode, it can also be used as a plasma electrode, and film deposition based on plasma CVD processes can be performed. When a voltage is applied to the ESC electrode by an external power source, the wafer placed on the surface of the ceramic plate 12 is held by the Johnson-Label force. The heater electrode is not particularly limited; for example, it can be obtained by wiring a conductive coil across the entire surface of the ceramic plate 12 in a single stroke. The heater electrode heats up when powered by a heater power source, heating the wafer placed on the surface of the ceramic plate 12. The heater electrode is not limited to a coil; for example, it can be a strip (a thin, elongated plate) or a mesh. Strip-shaped heater electrodes can be formed by printing.

[0062] MMC plate 14 is composed of a metal matrix composite (MMC). The MMC can be any known material in which a ceramic reinforcing material is incorporated into a metal matrix, and is not particularly limited. Examples of metal matrices include aluminum and metallic silicon. Examples of ceramic reinforcing materials include SiC and TiC. In a preferred embodiment of the present invention, the MMC may contain Si, C, and Ti. Examples of MMC containing Si, C, and Ti include a composite material containing 37-60% by mass of silicon carbide and containing titanium silicon carbide and titanium carbide in amounts less than the content (by mass) of silicon carbide. Another example of MMC containing Si, C, and Ti is a composite material containing 42-65% by mass of titanium silicide (TiSi2) and containing SiC, titanium silicon carbide, and titanium carbide in amounts less than the content of titanium silicide (TiSi2). The MMC containing Si, C, and Ti may further contain Al, or Al and N. That is, the MMC containing Si, C, and Ti can further contain Al, which can be contained in the form of AlN or other forms accompanied by N. By further containing Al, the bonding strength is increased. Examples of MMCs containing Si, C, Ti, Al, and N include composite materials containing 42-60% by mass of titanium silicide and containing SiC, titanium silicon carbide, titanium carbide, alumina, and aluminum nitride in amounts less than the content (by mass%) of titanium silicide. In another preferred embodiment of the invention, the MMC contains Al, Si, and C. Examples of MMCs containing Al, Si, and C include composite materials containing 60-80% by volume of SiC and containing aluminum in amounts less than the content (by volume%) of SiC. The thickness of the MMC plate 14 is not particularly limited, but is typically 5-35 mm.

[0063] The surface of the bonding interface 22 side of the MMC plate 14 preferably has an arithmetic mean roughness Ra of 0.01 to 1.0 μm, more preferably 0.05 to 0.70 μm. If the arithmetic mean roughness Ra is within the above range, the bonding strength can be improved more effectively. This is believed to be because: by ensuring Ra is not too high, the adhesion between the MMC plate 14 and the bonding layer 16 is improved; furthermore, by ensuring Ra is not too low, an anchoring effect can be obtained from the surface roughness or unevenness of the MMC plate 14.

[0064] The bonding layer 16 is a metal layer containing Al as the main component. The bonding layer 16 preferably also contains Si and / or Mg as secondary components, more preferably it also contains Si, or Si and Mg as secondary components. Here, "main component" refers to a component that occupies 80% by weight or more of the bonding layer 16. "Secondary component" refers to a component contained in a lower content than the main component (excluding unavoidable impurities). Therefore, the bonding material constituting the bonding layer 16 is preferably an Al alloy containing Si and free of Mg, or an Al alloy containing Si and Mg. The Si content in this Al alloy is preferably 5 to 15% by weight. When Mg is included, the Mg content in the aluminum alloy is preferably 0.1 to 5.0% by weight. That is, the bonding layer 16 is preferably composed of an Al alloy containing 5 to 15% by weight of Si, 0.5 to 5.0% by weight of Mg, and the balance containing Al and unavoidable impurities. When Mg is not included, the bonding layer 16 is preferably composed of an Al alloy containing 5 to 15% by weight of Si, and the balance containing Al and unavoidable impurities.

[0065] The bonding interface 20 between the ceramic plate 12 and the bonding layer 16 may include a Mg-containing layer 24. It is believed that the presence of the Mg-containing layer 24 at the bonding interface 20 improves the bonding strength between the ceramic plate 12 and the bonding layer 16, resulting in high bonding strength between the ceramic plate 12 and the MMC plate 14. The Mg-containing layer 24 is defined as a layer containing Mg at a higher concentration than its surroundings in an elemental mapping image obtained using EPMA (electron probe microanalysis). The Mg-containing layer 24 preferably also contains Al and O. In this case, the Al:Mg:O weight ratio in the Mg-containing layer 24 is preferably in the range of 1:0.01 to 0.50:0.001 to 0.100, more preferably in the range of 1:0.05 to 0.30:0.005 to 0.050. The Al:Mg:O weight ratio can be determined using EPMA. From the viewpoint of improving bonding strength, the thickness of the Mg-containing layer 24 is preferably 1 to 10 μm, more preferably 1 to 7 μm.

[0066] The bonding of the ceramic plate 12, the bonding layer 16, and the MMC plate 14 is preferably hot-pressed. Hot-pressing refers to the following method: the metal bonding film (equivalent to the bonding layer 16) is sandwiched between the two components to be bonded, and the two components are bonded under pressure while heated to a temperature lower than the liquidus temperature of the metal bonding film (see Patent Document 1).

[0067] MMC board 14 is preferably: such as Figure 2 As shown, from the bonding interface 22 between the bonding layer 16 and the MMC plate 14 to the specified depth D AlAn Al-enriched layer 26 is provided, in which Al is distributed at a higher concentration than in other parts of the MMC plate 14. As described above, by providing the Al-enriched layer 26, high bonding strength can be achieved between the MMC plate 14 and the ceramic plate 12. The Al-enriched layer 26 can typically be referred to as a layer obtained by the diffusion and enrichment of Al originating from the bonding layer 16; however, the MMC plate 14 itself can contain Al, therefore the source of Al in the Al-enriched layer 26 is irrelevant. The Al-enriched layer 26 is defined as follows: Figure 5B As illustrated, in the Al elemental mapping image obtained using EPMA, a layer containing Al at a high concentration (compared to other areas of the MMC plate 14) is observed in the region adjacent to the bonding interface 22 in the MMC plate 14. That is, it can be said that in the Al elemental mapping image, where pixels representing high Al concentration are continuously distributed from the bonding layer 16 to the region adjacent to the bonding interface 22 of the MMC plate 14, the Al observed at a high concentration in the aforementioned adjacent region of the MMC plate 14 originates from the bonding layer 16. Thus, the Al-enriched layer 26 is determined. The depth D of the Al-enriched layer 26... Al Preferably, it is 40 μm or more, more preferably 40 to 600 μm, even more preferably 50 to 500 μm, and particularly preferably 250 to 500 μm.

[0068] MMC board 14 can be like Figure 2 As shown, in addition to having an Al-enriched layer 26, the bonding interface 22 between the bonding layer 16 and the MMC plate 14 extends to a specified depth D. Mg It also includes a Mg diffusion layer 28 derived from Mg diffusion originating from the bonding layer 16. In this case, the Al enriched layer 26 and the Mg diffusion layer 28 at least partially overlap (i.e., portions belonging to both the Al enriched layer 26 and the Mg diffusion layer 28 exist in the MMC plate 14). It is believed that the Mg diffusion layer 28 can also contribute to the achievement of high bonding strength together with the Al enriched layer 26. The Mg diffusion layer 28 is defined as follows: as described later. Figure 5B As illustrated, in the Mg elemental mapping image obtained using EPMA, a layer containing a high concentration of Mg was observed in the region of MMC plate 14 adjacent to the bonding interface 22 (compared to other regions of MMC plate 14). That is, it can be said that in the Mg elemental mapping image, where pixels representing high Mg concentration are continuously distributed from the bonding layer 16 to the region of MMC plate 14 adjacent to the bonding interface 22, the Mg observed at a high concentration in the aforementioned adjacent region of MMC plate 14 originates from the bonding layer 16. This determines the Mg diffusion layer 28. The depth D of the Mg diffusion layer 28... Mg Preferably, the depth is 10–300 μm, more preferably 20–200 μm, and even more preferably 90–180 μm. Typically, the depth D of the Al-enriched layer 26 is… Al Depth D greater than Mg diffusion layer 28Mg (That is, satisfying D) Al >D Mg ).

[0069] The MMC plate 14 may have internal spaces such as flow paths for refrigerant to pass through. Accordingly, the MMC plate 14 becomes a configuration suitable for a cooling plate in an electrostatic chuck assembly.

[0070] The joint 10 exhibits a joint strength preferably of 200 MPa or more, more preferably 250 MPa or more, and even more preferably 300 MPa or more in a 4-point bending test. The 4-point bending test is performed in the order and conditions disclosed in the embodiments described later, and the maximum bending stress obtained therefrom is used as the joint strength. Since a high joint strength is desired, the upper limit is not particularly limited, typically 500 MPa or less, and more typically 450 MPa or less.

[0071] Method for manufacturing the joint

[0072] Regarding the joint of the present invention, as long as a joint with a specified layer structure is obtained, it can be manufactured by any method. Hereinafter, a preferred manufacturing method will be described.

[0073] First, prepare a ceramic plate, an MMC plate, and a bonding layer with internal electrodes implanted. Details of each component are as described above. The ceramic plate, MMC plate, and bonding layer can all use known components; however, they can also be appropriately manufactured based on known methods.

[0074] Next, the ceramic plate, MMC plate, and bonding layer are ultrasonically cleaned using organic solvents. Ultrasonic cleaning removes contaminants adhering to the surfaces of each component, improving the adhesion between the components and the bonding layer, resulting in high bonding strength. Preferred examples of organic solvents include acetone and isopropanol (IPA). By increasing the ultrasonic cleaning time, contaminants can be removed more thoroughly, promoting the movement and diffusion of elements such as Mg and Al during hot pressing. Therefore, by controlling the ultrasonic cleaning time, the formation / non-formation of a Mg-containing layer can be controlled during subsequent hot pressing, and the depth (thickness) of the Al-enriched layer and the Mg-containing layer can be varied. For example, by increasing the ultrasonic cleaning time, a Mg-containing layer can be formed, or the depth of the Al-enriched layer and the Mg-containing layer can be increased. From the viewpoint of more effectively removing contaminants adhering to the surfaces of each component, ultrasonic cleaning using acetone and ultrasonic cleaning using isopropanol (IPA) are preferred. The ceramic plate and MMC plate subjected to ultrasonic cleaning are preferably further cleaned by rinsing with running water using pure water, purging with N2 gas, wiping with cleaning paper impregnated with organic solvents (IPA, etc.), and drying. Furthermore, the bonding layer subjected to ultrasonic cleaning is preferably further cleaned by purging with N2 gas.

[0075] Using separately cleaned ceramic plates, MMC plates, and bonding layers, a bonded body is fabricated by hot pressing. For example, the bonding layer is sandwiched between the ceramic plate and the MMC plate, and hot pressing is performed at a pressure of 4 MPa to 30 MPa while heating to a temperature below the liquidus temperature of the bonding material film, thus bonding the ceramic plate and the MMC plate together via the bonding layer. The hot pressing temperature is preferably below the liquidus temperature of the bonding layer and at least about 30°C lower than the solidus temperature. For example, the liquidus temperature of an aluminum alloy containing 10 wt% Si and 1 wt% Mg is about 590°C, and its solidus temperature is about 560°C. Therefore, it can be said that the preferred hot pressing temperature is in the range of about 520°C or higher and below about 540°C. This allows for the formation of the bonded body of the present invention, in which the ceramic plate and the MMC plate are bonded together via the bonding layer.

[0076] Example

[0077] The invention will be further illustrated by the following examples. However, the invention is not limited to these examples.

[0078] Examples 1 to 9

[0079] (1) Production of ceramic slabs

[0080] As a ceramic plate, a circular alumina sintered body (thickness: 5 mm, diameter: 300 mm) with embedded ESC electrodes is manufactured as follows. First, first and second green sheets of disc-shaped alumina are prepared. An ESC electrode is formed on one surface of the first green sheet using screen printing, and a heater electrode is formed on one surface of the second green sheet using screen printing. Next, another green sheet of alumina (hereinafter referred to as a third green sheet) is stacked on the surface of the first green sheet where the ESC electrode is formed, and the second green sheet is stacked on top of the third green sheet with the heater electrode in contact with the third green sheet. The resulting laminate is fired using a hot pressing method, thereby obtaining a ceramic sintered body with embedded ESC electrodes and heater electrodes. Both sides of the obtained ceramic sintered body are subjected to grinding, sandblasting, etc., thereby adjusting the shape and thickness to obtain a flat electrostatic chuck as a ceramic plate. The specific manufacturing conditions for this electrostatic chuck are set with reference to the conditions described in Japanese Patent Application Publication No. 2006-196864.

[0081] (2) Fabrication of MMC board

[0082] As an MMC board, a board containing Si, C, and Ti (SiSiCTi board) is fabricated as follows. First, as raw materials, prepare commercially available SiC raw material (purity ≥ 97%, average particle size 15.5 μm), commercially available metallic Si raw material (purity ≥ 97%, average particle size 9.0 μm), and commercially available metallic Ti raw material (purity ≥ 99.5%, average particle size 31.1 μm). Weigh the SiC, metallic Si, and metallic Ti raw materials according to the following ratio: SiC: 49.5% by mass, Si: 20.0% by mass, Ti: 30.5% by mass. Place them together with isopropanol as a solvent in a nylon container and wet mix for 4 hours using nylon balls with an iron core and a diameter of 10 mm. Remove the resulting slurry, dry it in a nitrogen atmosphere at 110°C, and then pass it through a 30-mesh sieve to obtain a blended powder. The blended powder is then subjected to a 200 kgf / cm³ pressure... 2 The pressure is applied uniaxially to form a disc-shaped molded body with a diameter of approximately 50 mm and a thickness of approximately 17 mm, which is then placed in a graphite mold for firing. The disc-shaped molded body is then hot-pressed and fired to obtain the MMC board. This hot-pressing and firing process is performed as follows: 200 kgf / cm² is applied under a vacuum atmosphere. 2 The pressure is applied while maintaining the firing temperature (maximum temperature) at 1400℃ for 4 hours.

[0083] For the surfaces of the MMC boards prepared in this way that are to be bonded to the bonding layer, the arithmetic mean roughness Ra was measured using a stylus-type surface roughness meter according to JIS B 0601-2001. The results are shown in Table 1.

[0084] (3) Preparation of the bonding layer

[0085] To form the bonding layer, a 0.12 mm thick Al alloy sheet containing Si and Mg was prepared (alloy composition: Si: 10 wt%, Mg: 1 wt%, balance: Al and unavoidable impurities).

[0086] (4) Cleaning process

[0087] For ceramic plates and MMC plates, the following cleaning processes (i) to (vi) are performed in sequence. On the other hand, for Al alloy sheets containing Si and Mg, only the following cleaning processes (i), (ii) and (iv) are performed in sequence.

[0088] <Cleanliness Process>

[0089] (i) Ultrasonic cleaning with acetone (not performed in Example 9)

[0090] (ii) Ultrasonic cleaning using isopropyl alcohol (IPA) (not performed in Example 9)

[0091] (iii) Cleaning with pure water

[0092] (iv) Purging with N2 gas

[0093] (v) Drying at 120°C for 10 minutes

[0094] At this point, the total cleaning time for (i) ultrasonic cleaning using acetone and (ii) ultrasonic cleaning using isopropanol (IPA), i.e., the ultrasonic cleaning time in organic solvents, varied in each experimental example, as shown in Table 1. Therefore, as described above, for Example 9, ultrasonic cleaning as described in (i) and (ii) was not performed.

[0095] (5) Hot pressing

[0096] Using a cleaned ceramic plate, an MMC plate, and a bonding sheet, hot pressing is performed as follows: The bonding sheet is sandwiched between the ceramic plate and the MMC plate as a bonding layer. While heating to 530°C (a temperature lower than the liquidus temperature of the Al alloy containing Si and Mg but approximately 30°C lower than the solidus temperature), hot pressing is performed in a vacuum at a pressure of 20 MPa to bond the ceramic plate, bonding sheet (bonding layer), and MMC plate together. This results in a composite body where the ceramic plate and MMC plate are bonded together by means of the bonding layer.

[0097] (6) Evaluation of the joint

[0098] The following evaluation is made regarding the fabricated joint.

[0099] <Obtaining Element Mapping Images Using EPMA>

[0100] The cross-section of the obtained joint was cut out, mirror-polished, and then subjected to planar ion milling using Ar ions to obtain the observation section. A 75μm × 75μm region, including the ceramic plate 12, the joint interface 20, and the joint layer 16, was observed using a scanning electron microscope (SEM). Elemental analysis of this region was performed using an EPMA (manufactured by Nippon Electron Ltd.) under a measurement condition with an accelerating voltage of 15kV, yielding elemental mapping images of Si, C, Ti, O, Mg, and Al. Figure 3A and Figure 3B The table shows SEM images (Compo images) of cross-sections of the joint including ceramic plate 12, joint interface 20, and joint layer 16 in Example 7, as well as element-mapped images of the corresponding regions. The results are shown in Table 1. Figure 3A and Figure 3B As shown, in the joints of Examples 1 to 7, a Mg-containing layer 24 with a high concentration of Mg compared to its surroundings was observed at the joint interface 20, and it was also confirmed that the Mg-containing layer 24 also contained Al and O. On the other hand, no such Mg-containing layer was observed in the joints of Examples 8 and 9 (comparative examples).

[0101] In addition, the 75μm×75μm region in the obtained observation section, including the bonding layer 16, the bonding interface 22 and the bonding interface 22 with the MMC plate 14, was observed by SEM and analyzed by EPMA elemental analysis in the same manner as described above. Figure 4A and Figure 4B The diagram shows a SEM image (Compo image) of a cross-section of the joint including the bonding layer 16, the bonding interface 22, and the MMC plate 14 in Example 7, along with element-mapped images of the corresponding regions. As a result, in the joints of Examples 1-9, as... Figure 4A and Figure 4B As shown, a microstructure of TiC particles (black particles in the figure), TiSi2 matrix phase (gray portion in the figure), and SiC particles (white particles in the figure) was observed within the MMC plate 14 (SiSiCTi plate). Furthermore, in the conjugates of Examples 1-7, it was also confirmed that Mg and Al diffused into the SiSiCTi constituting the MMC plate 14.

[0102] In addition, regarding the wider 300μm×300μm cross-sectional area including the bonding layer 16, the bonding interface 22 and the bonding interface 22 with the MMC plate 14, the magnification was reduced and the concentration scale was narrowed. Otherwise, SEM observation and EPMA elemental analysis were performed in the same manner as described above. Figure 5A and Figure 5BThe diagram shows a reduced-scale version of the SEM image (Compo image) of a cross-section of the joint including the bonding layer 16, the bonding interface 22, and the MMC plate 14 in Example 7, along with elemental mapping images of the corresponding regions. As a result, in the joints of Examples 1-9, the presence of a partially Al-enriched layer 26 and a partially Mg-diffused layer 28, identified as originating from Al and Mg from the bonding interface 22 diffused along the depth direction of the MMC plate 14, was confirmed. The depth D of the Al-enriched layer 26 from the bonding interface 22 is shown. Al and the depth D of the Mg diffusion layer 28, calculated from the self-bonding interface 22. Mg The measurements were performed, and the results are shown in Table 1.

[0103] <Weight ratio of Al:Mg:O in the Mg-containing layer>

[0104] Based on the EPMA measurement results, semi-quantitative values ​​of each element per pixel equivalent to 0.24μm × 0.24μm were calculated. The weight ratio of Al:Mg:O was calculated using the average value of 300 pixels. The results showed that the Al:Mg:O weight ratios in the Mg-containing layer were 1:0.134:0.0238 (Example 1), 1:0.413:0.0961 (Example 2), 1:0.253:0.0479 (Example 3), 1:0.250:0.0532 (Example 4), 1:0.233:0.0196 (Example 5), 1:0.018:0.0099 (Example 6), and 1:0.141:0.0321 (Example 7).

[0105] <Joint strength>

[0106] From the obtained joint, a strip-shaped specimen was cut with the joint layer located at the center along its length. The surface of the specimen was ground to produce a test piece with dimensions of 1.5 mm × 2.0 mm × 20 mm. For this test piece, a four-point bending test was conducted with the joint interface as the center, under the conditions of a lower span of 15 mm, an upper span of 5 mm, and a crosshead speed of 0.5 mm / min. The maximum bending stress (MPa) obtained was taken as the joint strength. The results are shown in Table 1.

[0107] Table 1

[0108]

[0109] Examples 10~12

[0110] i) As the MMC board, a board containing Si, C, Ti, and Al (SiSiCTi+Al board) was used as shown below; ii) The ultrasonic cleaning time in the organic solvent was as shown in Table 2. Otherwise, the fabrication and evaluation of the bond were carried out in the same manner as in Example 1. The results are shown in Table 2.

[0111] (MMMC board manufacturing)

[0112] As an MMC board, a board containing Si, C, Ti, and Al (where Al can be in the form of AlN) is fabricated as follows. First, as raw materials, prepare commercially available SiC raw materials (purity ≥ 97%, average particle size 15.5 μm), commercially available metallic Si raw materials (purity ≥ 97%, average particle size 9.0 μm), commercially available metallic Ti raw materials (purity ≥ 99.5%, average particle size 31.1 μm), and commercially available AlN raw materials (purity ≥ 97%, average particle size 1.1 μm). Weigh the SiC raw materials, metallic Si raw materials, metallic Ti raw materials, and AlN raw materials according to the following proportions: SiC: 49.5% by mass, Si: 10.0% by mass, Ti: 30.5% by mass, AlN: 10.0% by mass. Place them together with isopropanol as a solvent into a nylon container and wet mix for 4 hours using nylon balls with an iron core and a diameter of 10 mm. The obtained slurry was removed and dried at 110°C in a nitrogen stream, then passed through a 30-mesh sieve to obtain a blended powder. The blended powder was then subjected to a nitrogen flow rate of 200 kgf / cm³. 2 The pressure is applied uniaxially to form a disc-shaped molded body with a diameter of approximately 50 mm and a thickness of approximately 17 mm, which is then placed in a graphite mold for firing. The disc-shaped molded body is then hot-pressed and fired to obtain the MMC board. This hot-pressing and firing process is performed as follows: 200 kgf / cm² is applied under a vacuum atmosphere. 2 The pressure is applied while maintaining the firing temperature (maximum temperature) at 1400℃ for 4 hours.

[0113] Examples 13~18

[0114] i) Use the Mg-free Al-Si bonding layer prepared as follows; ii) Perform hot pressing as follows; iii) Perform ultrasonic cleaning in organic solvent for the times shown in Table 2. Otherwise, the bonding assembly was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0115] (Preparation of the bonding layer)

[0116] To form the bonding layer, a Si and Al alloy sheet with a thickness of 0.12 mm was prepared (alloy composition: Si: 10% by weight, balance: Al and unavoidable impurities).

[0117] (Hot pressing)

[0118] Using a cleaned ceramic plate, an MMC plate, and a bonding sheet, hot pressing is performed as follows: The bonding sheet is sandwiched between the ceramic plate and the MMC plate as a bonding layer. While heating to 560°C (a temperature lower than the liquidus temperature of Si and Al alloys and approximately 30°C lower than the solidus temperature), hot pressing is performed in a vacuum at a pressure of 20 MPa to bond the ceramic plate, bonding sheet (bonding layer), and MMC plate together. This results in a composite body where the ceramic plate and MMC plate are bonded together by means of the bonding layer.

[0119] Examples 19~21

[0120] i) As an MMC board, a board containing Si, C, Ti, and Al (AlN) was used, similar to that in Example 10 (SiSiCTi+Al(AlN) board); ii) The ultrasonic cleaning time in the organic solvent was as shown in Table 2. Otherwise, the bonding assembly was fabricated and evaluated in the same manner as in Example 13. The results are shown in Table 2.

[0121] Examples 22~24

[0122] i) As an MMC board, an AlSiC board containing Si, C, and Al was used (AlSiC board); ii) The ultrasonic cleaning time in the organic solvent was as shown in Table 2. Otherwise, the fabrication and evaluation of the bond were performed in the same manner as in Example 13. The results are shown in Table 2.

[0123] (MMMC board manufacturing)

[0124] As an MMC board, a board containing Si, C, and Al is produced as follows. First, 5 parts by mass of PVB (polyvinyl butyral) and 5 parts by mass of colloidal silica are added as a binder to 100 parts by mass of SiC raw material as raw material powder. The resulting mixture is extruded to produce a porous ceramic molded body (preform). The obtained preform is preheated to 700°C and placed inside a mold of a pressure device. Next, aluminum alloy (AC3A) set to a molten state at 750°C is placed inside the mold, and a pressure of 30 MPa is applied to allow the molten aluminum alloy to permeate into the preform. The permeation treatment is performed for 10 minutes. Afterward, the composite material with aluminum alloy permeated into SiC is removed from the mold, and excess Al alloy adhering to the composite material is ground off to obtain an MMC board composed of an Al-SiC composite material with SiC accounting for 70% by volume.

[0125] Examples 25~27

[0126] i) An aluminum nitride sintered body prepared as follows was used as the ceramic plate; ii) The ultrasonic cleaning time in the organic solvent was as shown in Table 2. Otherwise, the preparation and evaluation of the joint were carried out in the same manner as in Example 19. The results are shown in Table 2.

[0127] (Making of ceramic slabs)

[0128] As a ceramic plate, a circular aluminum nitride sintered body (thickness: 5 mm, diameter: 300 mm) with embedded ESC electrodes is fabricated as follows. First, first and second green sheets of disc-shaped aluminum nitride are prepared. An ESC electrode is formed on one surface of the first green sheet using screen printing, and a heater electrode is formed on one surface of the second green sheet using screen printing. Next, another green sheet of aluminum nitride (hereinafter referred to as a third green sheet) is stacked on the surface of the first green sheet where the ESC electrode is formed, and the second green sheet is stacked on top of the third green sheet with the heater electrode in contact with the third green sheet. The resulting laminate is fired using a hot pressing method to obtain a ceramic sintered body with embedded ESC electrodes and heater electrodes. The two sides of the obtained ceramic sintered body are ground and sandblasted to adjust the shape and thickness, resulting in a flat electrostatic chuck as a ceramic plate.

[0129] Table 2

[0130]

[0131] Explanation of reference numerals in the attached figures

[0132] 10. Assembly

[0133] 12 Ceramic Plates

[0134] 14 MMC Board

[0135] 16 Bonding Layer

[0136] 18 Internal Electrodes

[0137] 20, 22 Joint interface

[0138] 24 Mg-containing layer

[0139] 26 Al-enriched layer

[0140] 28 Mg diffusion layer

Claims

1. A joint comprising: Ceramic slab; An MMC plate, configured to face one side of the ceramic plate, and composed of a metal matrix composite (MMC) comprising (i) Si, C, and Ti, or (ii) Al, Si, and C; and A bonding layer is disposed between the ceramic plate and the MMC plate to bond the ceramic plate and the MMC plate, and the bonding layer contains Al as the main component. The MMC board extends from the bonding interface between the bonding layer and the MMC board to a specified depth D. Al The Al-enriched layer has an Al concentration distributed at a higher level than other parts of the MMC plate, and the depth D of the Al-enriched layer is... Al It is above 40μm.

2. The joint according to claim 1, wherein, The metal matrix composite (MMC) contains Si, C and Ti, as well as Al, or Al and N.

3. The joint according to claim 1, wherein, The metal matrix composite (MMC) contains Al, Si, and C.

4. The joint according to claim 1, wherein, The bonding layer also contains Si as a secondary component.

5. The joint according to claim 4, wherein, The bonding layer also contains Mg as a secondary component.

6. The joint according to claim 5, wherein, The MMC board extends from the bonding interface between the bonding layer and the MMC board to a specified depth D. Mg A Mg diffusion layer derived from the Mg diffusion of the bonding layer.

7. The joint according to claim 6, wherein, The depth D of the Al enrichment layer Al The depth D of the Mg diffusion layer is greater than that of the Mg diffusion layer. Mg That is, satisfying D Al >D Mg .

8. The joint according to any one of claims 1 to 7, wherein, The ceramic plate comprises aluminum oxide and / or aluminum nitride and has internal electrodes embedded therein.

9. The joint according to any one of claims 1 to 7, wherein, The ceramic plate, the bonding layer, and the MMC plate are joined by thermoforming.

10. The joint according to any one of claims 1 to 7, wherein, The surface of the MMC plate on the interface side has an arithmetic mean roughness Ra of 0.01 to 1.0 μm.

11. The joint according to any one of claims 1 to 7, wherein, The joint strength exhibited above 200 MPa in the 4-point bending test.

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