JP6975598B2 - Manufacturing method of silicon carbide member - Google Patents

Description

The present invention relates to a method for manufacturing a silicon carbide member.

Silicon carbide (SiC) sintered bodies are widely used as fixing members in semiconductor manufacturing equipment, liquid crystal manufacturing equipment, and the like in view of their characteristics of high strength, high rigidity, and high wear resistance. However, since the silicon carbide sintered body is obtained by sintering silicon carbide powder, pores (voids) are inevitably present on the surface or inside of the structure, and the bonding force between particles is locally inferior. There was a risk of dust being generated by particles from the surrounding area.

Therefore, it has been studied to use a silicon carbide body formed by a chemical vapor deposition (CVD) method, which has higher strength and rigidity than a silicon carbide sintered body. However, this silicon carbide body is inferior in productivity and high cost as compared with the case of producing a silicon carbide sintered body. Therefore, it has been proposed to suppress low productivity and high cost by using a member in which a silicon carbide body formed by a CVD method is bonded to a silicon carbide sintered body.

For example, Patent Document 1 discloses that a base material portion made of a silicon carbide sintered body and a molded surface portion made of a silicon carbide body formed by a CVD method are joined via a bonding material.

Japanese Patent No. 4917844

However, structural members used in semiconductor manufacturing equipment and the like are often exposed to a corrosive environment such as a plasma etching process or a high temperature environment such as a film forming process, and are exposed to a bonding material as in Patent Document 1 above. Since the bonded material is inferior in plasma corrosion resistance and heat resistance as compared with a silicon carbide sintered body or the like, there is a problem that the structural member as a whole is inferior in plasma corrosion resistance and heat resistance.

The present invention has been made in view of the above-mentioned conventional problems, and manufactures a silicon carbide member capable of bonding a silicon carbide sintered body and a silicon carbide body formed by a CVD method without using a bonding material. The purpose is to provide a method.

The method for producing a silicon carbide member of the present invention includes a first polishing step of polishing the joint surface of a first silicon carbide member made of a silicon carbide sintered body, and a second carbonization formed by a chemical vapor phase growth method. The second polishing step of polishing the joint surface of the silicon member, and the joint surface of the first silicon carbide member polished and the joint surface of the polished second silicon carbide member in an inert atmosphere. By directly contacting the first silicon carbide member and pressing the second silicon carbide member toward the respective joint surfaces, the contacted surface is heated while applying pressure. By doing so, it has a joining step of joining the first silicon carbide member and the second silicon carbide member, and the first silicon carbide member and the second silicon carbide member in the pressed direction. It is characterized in that the dimensional reduction rate is 0.125 to 1%.

According to the method for manufacturing a silicon carbide member of the present invention, as can be seen from Examples described later, a first silicon carbide member made of a silicon carbide sintered body and a chemical vapor phase growth method are used without using a bonding material. It becomes possible to directly join the formed second silicon carbide member. If the dimensional reduction rate of the first and second silicon carbide members is less than 0.125%, the first silicon carbide member and the second silicon carbide member are not sufficiently bonded. On the other hand, if the dimensional reduction rate of the first and second silicon carbide members exceeds 1%, the deformation of the first and second silicon carbide members becomes too large, and the desired shape cannot be maintained, so that many additional operations are performed. Is required. The smaller the dimensional reduction rate of the first and second silicon carbide members, the easier it is to design the shape of the silicon carbide member after joining.

The method of manufacturing a silicon carbide member of the present invention, in the bonding step, heated at 2,000 to 2,200 ° C..

This is because if the bonding temperature is less than 2000 ° C, the first silicon carbide member and the second silicon carbide member are not sufficiently bonded, and if the bonding temperature exceeds 2200 ° C, the first and second silicon carbide members are carbonized. This is because the deformation of the silicon member becomes too large, the desired shape cannot be maintained, and a large amount of additional machining is required, which leads to a decrease in productivity and an increase in cost.

In the method of manufacturing the silicon carbide member of the present invention, in the bonding step, Ru applying a pressure of 0.1~10MPa to the joint surface in contact with.

This is because if the bonding pressure is less than 0.1 MPa, the first silicon carbide member and the second silicon carbide member are not sufficiently bonded, and if the bonding pressure exceeds 10 MPa, the first and second silicon carbide members are carbonized. This is because the deformation of the silicon member becomes too large, the desired shape cannot be maintained, and additional machining is required.

Further, in the method for manufacturing a silicon carbide member of the present invention, in the first polishing step, the joint surface of the first silicon carbide member is polished to a surface roughness Ra of 0.005 to 0.4 μm, and the first polishing step is performed. In the polishing step 2, it is preferable to polish the joint surface of the second silicon carbide member until the surface roughness is 0.001 to 0.4 μm.

This is because if the surface roughness Ra of the bonded surfaces exceeds 0.4 μm, insufficient contact between the bonded surfaces occurs in the bonding process, the bonding becomes insufficient, and peeling may occur. On the other hand, since the surface roughness of the joint surface is affected by the pores contained in the first and second silicon carbide members, the surface roughness Ra of the joint surface of the first silicon carbide member is less than 0.005 μm, or It is difficult to make the surface roughness Ra of the joint surface of the second silicon carbide member less than 0.001 μm.

A schematic cross-sectional view of a method for manufacturing a silicon carbide member according to an embodiment of the present invention is shown, FIG. 1A shows the first and second polishing steps, FIG. 1B shows a joining step, and FIG. 1C shows a state after the joining step. The flowchart of the manufacturing method of the silicon carbide member which concerns on embodiment of this invention. The graph which shows the dimensional reduction rate of the 1st silicon carbide member. A photograph of the bonding interface of the silicon carbide member observed with a microscope is shown, FIG. 4A shows Example 1 and FIG. 4B shows Example 2.

A method for manufacturing a silicon carbide (SiC) member according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. The present manufacturing method includes first and second polishing steps S1 and S2 and a joining step S3.

First, as shown in FIG. 1A, a first polishing step S1 for polishing the joint surface 11 of the first silicon carbide member 10 made of a silicon carbide sintered body is performed. The silicon carbide sintered body uses granules granulated from a raw material obtained by adding a binder, a dispersant, etc. to silicon carbide powder, and forms such as atmospheric pressure molding, press molding, CIP molding, and atmospheric pressure sintering, addition. It may be manufactured by a sintering method such as pressure sintering or reaction sintering. Boron carbide, graphite and the like may be added to the raw material powder as a sintering aid.

In the first polishing step S1, it is preferable to polish the joint surface 11 of the first silicon carbide member 10 until the surface roughness Ra is 0.005 to 0.4 μm.

In addition, a second polishing step S2 for polishing the joint surface 21 of the second silicon carbide member 20 formed by the chemical vapor deposition (CVD) method is performed. The second silicon carbide member 20 may be formed by a conventionally known CVD method such as a thermal CVD method, a plasma CVD method, a super growth method, or an alcohol CVD method.

In the second polishing step S2, it is preferable to polish the joint surface 21 of the second silicon carbide member 20 until the surface roughness is 0.001 to 0.4 μm.

The polishing in the first and second polishing steps S1 and S2 is preferably performed by grinding with a surface grinder, a machining center or the like, and then polishing with a grindstone. Further, it is also preferable to polish with a grindstone and then further polish with a lapping machine, a polishing machine or the like. If the surface roughness Ra of the joint surfaces 11 and 21 exceeds 0.4 μm, insufficient contact between the joint surfaces 11 and 21 will occur in the joint step S3, resulting in insufficient joining and peeling may occur. be.

Further, the flatness of the joint surfaces 11 and 12 is preferably 10 μm or less, and more preferably 5 μm or less. When the flatness of the joint surfaces 11 and 12 exceeds 10 μm, even if the first silicon carbide member 10 and the second silicon carbide member 20 are pressed toward the joint surfaces 11 and 21, respectively, in the joining step S3 described later. This is because the contact between the joint surfaces 11 and 21 may be insufficient, the joint may be insufficient, and peeling may occur.

Then, as shown in FIG. 1B, N _2, Ar, under an inert atmosphere such as a vacuum atmosphere, the second silicon carbide member 20 which is polished and the joining surface 11 of the first silicon carbide member 10 which is polished The contact surface 11 is brought into direct contact with the joint surface 21 and the first silicon carbide member 10 and the second silicon carbide member 20 are pressed toward the respective joint surfaces 11 and 21 respectively. , 21 is heated while applying pressure to join the first silicon carbide member 10 and the second silicon carbide member 20 to perform the joining step S3 to obtain the silicon carbide member 30. As a result, the silicon carbide member 30 that is not joined via the joining material can be obtained.

In the joining step S3, it is preferable to heat at a temperature of 2000 to 2200 ° C. If the bonding temperature is less than 2000 ° C., the first silicon carbide member 10 and the second silicon carbide member 20 are not sufficiently bonded. On the other hand, if the joining temperature exceeds 2200 ° C., the deformation of the first and second silicon carbide members 10 and 20 becomes too large, the desired shape cannot be maintained, and additional machining is required.

In the joining step S3, it is preferable to apply a pressure of 0.1 to 10 MPa to the contacted joint surfaces 11 and 21. If the joining pressure is less than 0.1 MPa, the first silicon carbide member 10 and the second silicon carbide member 20 are not sufficiently joined. On the other hand, if the joining pressure exceeds 10 MPa, the deformation of the first and second silicon carbide members 10 and 20 becomes too large, the desired shape cannot be maintained, and additional machining is required.

In the joining step S3, it is preferable to press the first silicon carbide member 10 and the second silicon carbide member 20 so that the dimensional reduction rate T is 0.125 to 1% in the pressing direction. Here, the dimensional reduction rate T of the first silicon carbide member 10 and the second silicon carbide member 20 is the first in the pressing direction (in the case of pressing in the thickness direction, the thickness direction) before the joining step S3. The sum of the length of the silicon carbide member 10 and the length of the second silicon carbide member 20 of the above, and L2 is the silicon carbide member 30 in the pressing direction (thickness direction when pressed in the thickness direction) after the joining step S3. It is expressed by the formula (L1-L2) / L1 × 100 in the case of “the length of”.

When the dimensional reduction rate T of the first silicon carbide member 10 and the second silicon carbide member 20 is less than 0.125%, the first silicon carbide member 10 and the second silicon carbide member 20 are sufficiently bonded. do not. On the other hand, when the dimensional reduction rate T of the first silicon carbide member 10 and the second silicon carbide member 20 exceeds 1%, the deformation of the first and second silicon carbide members 10 and 20 becomes too large, which is desired. The shape cannot be maintained and a lot of additional machining is required.

The dimensional reduction rate T of the first silicon carbide member 10 and the second silicon carbide member 20 depends on the joining temperature, the joining pressure, the joining time, and the like. The dimensional reduction rate T of the first silicon carbide member 10 and the second silicon carbide member 20 increases as the bonding temperature increases, the bonding pressure increases, and the bonding time increases.

FIG. 3 is a graph showing the dimensional reduction rate T of the first silicon carbide member 10 and the second silicon carbide member 20 when the joining temperature and the joining pressure are changed and the other joining conditions are constant. As can be seen from this graph, the first silicon carbide member 10 made of the silicon carbide sintered body and the second silicon carbide member 20 formed by the CVD method are compared with the case where the silicon carbide sintered bodies are joined to each other. It can be seen that the dimensional reduction rate T of the first silicon carbide member 10 and the second silicon carbide member 20 becomes smaller when the first silicon carbide member 10 and the second silicon carbide member 20 are joined.

The present invention is not limited to the above-described embodiment. For example, a plurality of joint surfaces 11 of the first ceramic member 10, for example, the front and back surfaces may be used as the joint surfaces 11, and the second ceramic member 20 may be bonded to the respective joint surfaces 11.

Hereinafter, the present invention will be described in detail with reference to specific examples of the present invention.

(Example)
First, the first silicon carbide member 10 was manufactured by a well-known process for forming a silicon carbide sintered body. _{Specifically, B 4} C is 0.1 to 0.5% by mass, C (carbon black) is 2 to 4% by mass as a sintering aid, and molding aid is added to the silicon carbide powder having an average particle size of 1 μm or less. The raw material powder was prepared by adding a binder such as PVA as an agent. As the silicon carbide powder, α-type (hexagonal) powder was used.

Next, this raw material powder was granulated by a spray dryer or the like and then molded under atmospheric pressure. Then, the first silicon carbide member 10 was obtained from the silicon carbide sintered body by firing at 2000 ° C. to 2200 ° C. in an argon atmosphere. The obtained first silicon carbide member 10 was α-type (hexagonal).

The first silicon carbide member 10 was formed into a disk shape having a diameter of 100 mm and a thickness of 3.5 mm by grinding. Then, in the first polishing step S1, one surface (lower surface of FIG. 1A) was polished with a # 800 grindstone until the surface roughness Ra became 0.4 μm. Then, the surface roughness Ra was further polished to 0.01 μm using free abrasive grains of diamond having a particle size of 1 μm. At the center of the first silicon carbide member 10, a through hole having a diameter of 5 mm was formed so as to penetrate between the upper surface and the lower surface of FIG. 1A. This through hole is a test port used for the airtightness evaluation described later.

Further, the second silicon carbide member 20 was manufactured by a well-known process for forming a silicon carbide body by a CVD method. Specifically, the second silicon carbide member 20 was formed by a thermal CVD method in which a silicon carbide body was formed on a high-purity isotropic graphite material by heat film formation. As a raw material gas, _{a mixed gas of trichloromethylsilane (CH 3} SiCl ₃ : MTS) and hydrogen gas was used. A second silicon carbide member 20 was obtained by removing the graphite material after the film formation. The obtained second silicon carbide member 20 was β-type (cubic).

The second silicon carbide member 20 was formed into a disk shape having a diameter of 100 mm and a thickness of 4.5 mm by grinding. Then, in the second polishing step S2, one surface (upper surface of FIG. 1A) was polished with a # 800 grindstone until the surface roughness Ra became 0.4 μm. Then, the surface roughness Ra was further polished to 0.005 μm using free abrasive grains of diamond having a particle size of 1 μm.

Next, in the joining step S3, the first and second silicon carbide members 10 and 20 are placed in a firing furnace in a state of being in contact with the joining surfaces 11 and 21, and reach the maximum temperature in an Ar atmosphere. Then, it was fired for 6 hours to obtain a silicon carbide member 30.

The firing temperature and firing pressure in the joining step S3, and the thickness change amount (pressing direction change amount) L1-L2 and the thickness change rate (dimension decrease rate) T of the first silicon carbide member 10 and the second silicon carbide member 20 are determined. It is shown in Table 1.

When the silicon carbide member 30 was cut and the interface between the originally first silicon carbide member 10 and the second silicon carbide member 20 was observed with a microscope microscope, the α-type originally first silicon carbide member 10 was observed. It was observed that no local gap was formed at the bonding interface with the β-type originally second silicon carbide member 20 due to insufficient pressing, and the bonding was good.

FIG. 4A shows a photograph of the interface of Example 1 and FIG. 4B shows a photograph of the interface of Example 2 observed with a microscope.

Table 1 shows the results of evaluating the airtightness of the bonding interface of the first and second silicon carbide members 10 and 20 using the He leak detector as the leak amount. As a method for evaluating the airtightness, a pipe for a He leak detector was arranged at the test port of the silicon carbide member 30, and the amount of leakage when helium was sprayed on the side surface of the silicon carbide member 30 was measured. In Examples 1 to 6 in which the thickness change rate was 0.125% or more, the leak amount was suppressed to 10-9 Pa · m3 / s or less, so that sufficient airtightness was obtained and good bonding was obtained. I was able to confirm that it was there. In Examples 1 to 4 and 6 in which the bonding was performed at 2000 ° C. or higher, the leak amount was 10-10 Pa · m3 / s or less, and it was confirmed that more excellent airtightness could be obtained. Example 5 in which the bonding was performed at a temperature lower than 2000 ° C. is outside the scope of the present invention.

(Comparative example)
The silicon carbide member 30 of Comparative Example 1 was produced by the same method as in Example 1 except that the bonding temperature was changed. In Comparative Example 1, since the thickness change rate was too small, the amount of leakage was large, and the first silicon carbide member 10 and the second silicon carbide member 20 could not be satisfactorily bonded.

10 ... 1st silicon carbide member, 11 ... joint surface, 20 ... second silicon carbide member, 21 ... joint surface, 30 ... silicon carbide member, S1 ... first polishing step, S2 ... second polishing step, S3 ... Joining process.

Claims (2)

The first polishing step of polishing the joint surface of the first silicon carbide member made of the silicon carbide sintered body, and
A second polishing step of polishing the joint surface of the second silicon carbide member formed by the chemical vapor deposition method, and
In an inert atmosphere, the bonded surface of the polished first silicon carbide member and the bonded surface of the polished second silicon carbide member are directly brought into contact with the first silicon carbide member. By pressing the second silicon carbide member toward the respective joint surfaces, the first silicon carbide member and the second silicon carbide member are heated while applying pressure to the abutted joint surfaces. Has a joining process to join the silicon carbide member of
The dimensional reduction rate of the first silicon carbide member and the second silicon carbide member in the pressed direction is 0.125 to 1%.
Wherein in the bonding step, only one pressure 0.1~10MPa to the joint surface in contact with, the method for manufacturing the silicon carbide member, which comprises heating at a temperature of from 2000 to 2,200 ° C.. In the first polishing step, the joint surface of the first silicon carbide member is polished to a surface roughness Ra of 0.005 to 0.4 μm.
The production of the silicon carbide member according to claim 1 , wherein in the second polishing step, the joint surface of the second silicon carbide member is polished to a surface roughness Ra of 0.001 to 0.4 μm. Method.

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