JP2009242173A - Method for joining silicon carbide sintered compact - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for joining a silicon carbide sintered compact which can obtain a joined body in which a position shift after joining is reduced, further joining strength and airtightness are high, and, even in the case of being provided with a hollow part, the dimensional precision of the hollow part is excellent. <P>SOLUTION: The method for joining the first member composed of a silicon carbide sintered compact having a counter boring part and the second member composed of a silicon carbide sintered compact into which the counter boring part is inserted by metal silicon includes: a melting stage where metal silicon is packed into the counter boring part, and thereafter, heating is caused, so as to melt the metal silicon in the counter boring part; a working stage where the melted metal silicon is cooled and solidified, and thereafter, the metal silicon layer formed at the counter boring part is ground, so as to control its thickness; and a joining stage where the second member is inserted into the counter boring part, and heating is caused. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a method for joining silicon carbide sintered bodies. In particular, the present invention relates to a joined body suitable for a member that requires airtightness and high adhesion at a joint. For example, the present invention can be applied to a liquid recovery unit in an immersion exposure apparatus and a shower plate which is a gas supply unit such as a CVD apparatus.

SiC is excellent in heat resistance and corrosion resistance, and is widely used as a member for semiconductor manufacturing equipment. However, SiC has a high sintering temperature, and the atmosphere is also carried out under an inert gas. Is limited in size. In particular, in an immersion exposure apparatus, a CVD apparatus, or the like, there is a member having a shape that is difficult to be integrally formed such that a minute groove or hole for supplying or recovering liquid or gas is formed and a hollow portion is formed. In order to solve such a problem, various joining techniques have been proposed.

For example, in Patent Document 1, a first part that provides a female joint member for receiving and a second part that provides a male joint member for insertion are each in a direction in which the male member is inserted into the female member. Having opposite side walls substantially parallel to each other and shaped to provide an average gap of up to about 0.003 inch (0.076 mm) between the side walls, the female member further comprising a male member Reservoir means for containing silicon when inserted into the reservoir means, the reservoir means is filled with solid silicon, the male member is inserted into the female member, and the first and second parts are above the melting point of silicon. A method is disclosed in which heated and melted silicon is drawn into the gap by capillary action, and then both members are joined by cooled and solidified silicon.

Further, Patent Document 2 discloses that both of the carbonized carbons are solidified by solidifying molten Si present in a gap formed by loosely fitting the second silicon carbide sintered body in the loosely fitting recess of the first silicon carbide sintered body. The silicon sintered body is joined, and a horizontal gap and a vertical gap are formed in the gap. The vertical gap is 0.1 mm or more and 0.2 mm or less, and the first and second silicon carbide sintered bodies 1, A method of joining 2 in the horizontal direction and the vertical direction simultaneously is disclosed.

JP-A-10-87376 JP 2007-302500 A

However, as disclosed in these documents, it is difficult to make the filling rate of the metal silicon powder constant in the method of filling and bonding the metal silicon powder, and the positional deviation in the height direction is controlled after the bonding. It was difficult. In addition, since the amount of metallic silicon that melts and oozes out cannot be controlled, there is a problem that in joining of members having fine and complicated shapes, shape accuracy cannot be obtained due to oozing, and grooves and holes are buried. It was happening.

Further, when the metal silicon powder is melted, voids are likely to be generated inside the metal silicon due to bubbles or the like, thereby causing a problem that the bonding strength and airtightness are lowered.

Furthermore, Patent Document 2 also gives an example in which metal silicon of a plate material is used as a bonding material. However, when the plate material is sandwiched, shape accuracy such as thickness and parallelism of the plate material is strictly required. Furthermore, since the shape of the plate material cannot be completely matched with the shape of the joint, there is inevitably a gap between the members in the state before melting, so there is no way to reliably fill this when melting, As with the method of filling, the bonding strength and the airtightness may not be obtained.

In particular, when joining a plurality of locations at the same time, if even a slight misalignment occurs, a gap is generated at any location, making it very difficult to ensure airtightness at all locations. In addition, in order to prevent gaps, if a large amount of bonding material is used, the amount of seepage from the bonded portion increases.For example, in the case of a bonded body having a hollow portion, the shape accuracy of the hollow portion cannot be obtained and is blocked. There was a problem.

The present invention has been made in view of these problems, and has a small positional deviation after joining, a high joining strength and airtightness, and a joined body excellent in shape accuracy of the hollow part even when it has a hollow part. A method for joining silicon carbide sintered bodies is obtained.

In order to solve these problems, a first member made of a silicon carbide sintered body having a counterbore part and a second member made of a silicon carbide sintered body inserted into the counterbore part are joined by metallic silicon. A melting step of filling the counterbored portion with metal silicon and heating to melt the metal silicon in the counterbored portion; and a metal silicon layer formed on the counterbored portion after cooling and solidifying the molten metal silicon A bonding method of a silicon carbide sintered body is provided that includes a processing step of adjusting the thickness by grinding and a bonding step of inserting and heating a second member into the counterbore portion.

In the present invention, metallic silicon is used as the bonding material, but it is once melted at the bonded portion. As described in Patent Documents 1 and 2, when the silicon carbide sintered bodies are joined together with the melting of the metal silicon powder, the positional deviation when the metal silicon powder is melted is remarkable, and the shape after the joining is distorted. Is likely to occur. On the other hand, as in the present invention, once melted, misalignment can be suppressed to a minimum even if remelted, so that the shape after joining is not likely to go wrong.

In the present invention, the metal silicon layer formed in the melting step is ground to adjust its thickness. By grinding the surface of the metal silicon layer by grinding and removing the layer that hinders the melting of the oxide film, the carbide film, etc., the melting occurs smoothly and the adhesion with the second member can be enhanced. .

After the molten metal silicon is cooled and solidified, the metal silicon layer before grinding is preferably formed by wetting and adhering at least the entire bottom surface and part of the side surface of the counterbore part, more preferably the metal It is desirable for the silicon layer to fill the counterbore. As described above, since the metal silicon layer without voids is formed in advance along the shape of the counterbored portion before bonding, adhesion can be improved without voids entering in the bonding step.

In the processing step, the thickness of the metal silicon layer is preferably 0.1 to 0.3 mm. This is for suppressing the seepage of the bonding material. Within such a range, the thickness can be easily adjusted, and it is possible to prevent problems such as inaccuracy and blockage of fine holes due to bleeding. Furthermore, even when it has a plurality of joints, it is possible to reliably join without causing gaps in some places due to positional misalignment.

In the present invention, it is desirable that the gap formed when the second member is inserted into the counterbore is smaller than 0.1 mm. If it is 0.1 mm or more, not only the positional deviation in the horizontal direction but also the positional deviation in the height direction becomes large, which is not preferable. The gap is preferably 0.02 mm or more. This is because, if it is smaller than this, the amount of seepage increases. In addition, the clearance gap here means the average of the clearance gap which can be formed in the both sides of the insertion part of a 2nd member. Accordingly, it is desirable that the difference between the width of the counterbore part and the width of the portion into which the second member is inserted is smaller than 0.2 mm and 0.04 mm or more.

According to the present invention, a bonding layer in close contact with the first member and the second member is formed. The joining layer here is a layer formed between the bottom surface of the counterbore part of the first member and the surface of the second member substantially parallel thereto. There is no gap between the bonding layer and the first and second members, and the airtightness is extremely high because there is no gap inside the bonding layer.

As described above, a dense and tightly bonded bonding layer without voids is obtained by previously melting before bonding to form a dense metal silicon layer without voids in the counterbore part and further grinding. This is because the contact with the member is enhanced.

As described above, in the present invention, since the metal silicon layer is processed to a predetermined thickness, even if there are two or more joint portions between the first member and the second member, some locations are displaced due to misalignment. It becomes possible to join without generating a gap.

Therefore, the joining method of the present invention can be suitably used for joining in which a hollow portion is formed by joining the first member and the second member.

Provided is a method for joining silicon carbide sintered bodies in which a positional deviation after joining is small, joining strength and airtightness are high, and a joined body having a hollow portion having excellent shape accuracy can be obtained even when the hollow portion is provided. it can.

Hereinafter, the silicon carbide sintered body joining method of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic view showing a joining method of the present invention.

FIG. 1A shows a first member 11 made of a silicon carbide sintered body having a counterbore portion 11a.

The silicon carbide sintered body can be produced by a molding method such as press molding, CIP molding, or cast molding, and a sintering method such as atmospheric pressure sintering, pressure sintering, or reactive sintering. The counterbore part may be processed by processing the green body before sintering, or by grinding the sintered body with a machining center or the like. However, it is desirable to grind the sintered body from the viewpoint of shape accuracy.

About the depth of a counterbore part, it is preferable to set it as the depth of 10 to 30% with respect to the width | variety of the counterbore part 11a. This is because if the depth is too shallow, exudation occurs, and if it is too deep, voids are likely to occur.

In FIG. 1B, after filling the counterbore part 11a of the first member 11 with metal silicon, the metal silicon layer 13 (the metal silicon layer before processing is formed as 13a) is heated and melted in the counterbore part. It is the figure which showed the fusion | melting process which forms.

The metal silicon to be filled may have any shape such as powder, particle, block, plate, etc., but as shown in FIG. 1B, the metal silicon layer 13a has a sufficient amount to fill the counterbore. It is desirable to fill. By forming the metal silicon layer so as to fill the counterbore in this way, it is possible to reliably adjust the thickness of the subsequent metal silicon layer. The purity of the metal silicon is preferably 97% or more, more preferably 99 %% or more, and still more preferably 99.9% or more. This is because when there are many impurities, the melting temperature is lowered, and problems such as seepage occur.

The heating in the melting step is preferably in a vacuum, the heat treatment temperature is preferably 1410 to 1500 ° C. at which metal silicon is melted, and the heat treatment time is preferably 10 to 60 minutes.

As shown in FIG. 1B, the shape of the counterbored portion of the metal silicon layer 13a obtained by cooling after melting is preferably filled, and at least the entire bottom surface 111 and a predetermined height from the bottom surface. It is preferable that a part of the side surface 112 and the metal silicon are formed so as to be in close contact with each other. In order to form the metal silicon layer in this manner, it is preferable that a sufficient amount of metal silicon is melted than the volume of the counterbore part, or that the wettability is improved on the bottom and side surfaces of the counterbore part. Such treatment includes applying carbon.

FIG. 1C is a view showing a state after a processing step in which a metal silicon layer is processed to form a metal silicon layer 13b having a predetermined thickness. By performing processing in this way, airtight joining with sufficient strength with the second member becomes possible. A known processing method such as a machining center can be applied to form the metal silicon layer 13b. By setting the thickness of the metal silicon layer to 0.1 to 0.3 mm in the processing step, even when there are a plurality of joints, it is possible to reliably join without causing gaps in some locations due to misalignment. It becomes possible to do. In addition, since the bleeding of the bonding material can be suppressed, it is possible to prevent inconveniences such as inaccuracy and blockage of fine holes, and it is possible to obtain a bonded body having excellent hollow portion shape accuracy even when it has a hollow portion. it can.

In addition, in FIG. 1, although the counterbore part 11a of a junction part has shown the example of the same height, this invention is not limited to this, As it comprises several junction parts from which height differs It can also be applied to bonding.

Next, the 2nd member 12 is inserted in the counterbore part in which the metal silicon layer 13b was formed, and it heats and joins. Since the thickness of the metal silicon layer 13b is adjusted, as shown in FIG. 1D, when the second member 12 is inserted, the metal silicon layer 13b reliably contacts the metal silicon layer 13b. Then, when the metal silicon layer is remelted, the metal silicon can be reliably bonded without oozing out or without the gap of the bonding layer becoming uneven. In the step of FIG. 1D, it is desirable that the gap G formed when the second member is inserted into the counterbore part is smaller than 0.1 mm. If it is 0.1 mm or more, not only the positional deviation in the horizontal direction but also the positional deviation in the height direction becomes large, which is not preferable. The gap G is preferably 0.02 mm or more. This is because, if it is smaller than this, the amount of seepage increases.

As in the melting step, the heating in the joining step is preferably in vacuum, the heat treatment temperature is preferably 1410 to 1500 ° C. at which the metal silicon is melted, and the heat treatment time is preferably 30 to 60 minutes. Moreover, it is desirable to apply a load of 4 to ²⁰ g / cm ² at the time of joining. If a load larger than this is applied, silicon carbide is generated at the joint and the joint strength is likely to be lowered, which is not preferable.

It is preferable to adjust the thickness of the bonding layer L after bonding to 0.05 to 0.2 mm. It is possible to adjust the thickness of the metal silicon layer to the above range by adjusting the thickness, and further adjusting the heat treatment temperature, time, and load.

In FIG. 1E, a hollow portion 14 is formed in the joined body 10. Thus, the joining method of the present invention is suitable for joining having a hollow portion. The hollow portion may be a box shape that forms a closed space or a groove shape that forms a through hole. Since the metallic silicon of the bonding material does not ooze out and close the hollow portion, it is suitable for manufacturing a bonded body having a fine hollow portion.

Hereinafter, the present invention will be described with reference to examples and comparative examples.

The silicon carbide sintered body to be bonded was produced by using a commercially available silicon carbide powder (UF-10 manufactured by Stark Co.), molded by CIP method, and fired at 2100 ° C. in argon.

As for the shape of the silicon carbide sintered body, as shown in the first member 11 of FIG. 1, the counterbore part (width 2.5 mm, depth 0.5 mm, length 80 mm) is formed at a width of 20 mm, depth. A plate-shaped first member having a thickness of 80 mm and a thickness of 25 mm is used, and the other part is formed at a substantially central portion with a width of 5.1 mm, a depth of 5 mm, and a length of 80 mm as shown in the second member 12 of FIG. A second member having a width of 9.9 mm, a depth of 80 mm, and a thickness of 7.5 mm having a groove to be formed was formed. These shape processings were performed by known methods such as surface grinding and machining centers.

Next, in order to form a metal silicon layer on the counterbore, a slurry obtained by adding distilled water to metal silicon powder (purity 99.9%, D50 by laser diffraction particle size distribution meter): 2.23 μm is used. The counterbore was filled. At this time, a wall was provided around the counterbore so that a sufficient amount of metal silicon could be filled. After drying to remove moisture, the mixture was held at 1450 ° C. in a vacuum for 10 minutes, melted and then cooled. Metallic silicon was formed so as to fill the counterbore part.

Thereafter, as shown in FIG. 1D, the metal silicon layer was processed to a thickness of 0.15 mm by a machining center. The joining process was performed by holding at 1450 ° C. for 60 minutes in a vacuum as in the case of melting. As a result, a joined body having a hollow portion (through hole: width 5.1 mm, height 4.6 mm, length 80 mm) was obtained as shown in FIG.

For comparison, a joined body was manufactured using the first member and the second member having the same shape without going through the melting step and the processing step in the present invention. As the bonding material, the above-described metal silicon powder and a metal silicon substrate (thickness 0.2 mm) were used. In the case of metallic silicon powder, a powder in which the powder was simply filled in the counterbore part and a paste in which a binder was added to form a paste were prepared. In any of the examples, after filling the bonding material, the second member was inserted and the heat treatment for bonding was performed under the same conditions as in the above manufacturing example without performing the melting step.

The results are shown in Table 1. In the airtight test, jigs for testing were attached to both ends of the through hole, high pressure air of 0.5 MPa was introduced, and it was examined whether there was any leakage from the joint. About the joining layer, the cut surface was observed with the optical microscope, and the thickness and the presence or absence of the space | gap were investigated. For the joint strength, a joint for a joint strength test is separately prepared under the same conditions, a test piece (3 mm × 4 mm × 40 mm) is cut out from the joint, and a four-point bending test with a lower span of 30 mm and an upper span of 10 mm (conforms to JISR1624). ) To obtain the bonding strength.

In Production No. 1 which is an example of the present invention, the adhesion between the member and the bonding layer was good, and the bonding layer had no voids such as bubbles, so that it had sufficient bonding strength and good airtightness. There was no blockage due to seepage of the bonding material, and the shape accuracy of the inner surface of the through hole was good. On the other hand, in Production No. 2 of the comparative example, since the powder filling rate was poor, voids were generated and the bonding strength was insufficient. In Production No. 3 using a paste, the added binder and metal silicon reacted to generate silicon carbide. Since this reaction sintered silicon carbide is brittle, its bonding strength was insufficient. Further, since the binder was volatilized, the air gap was generated, and airtightness was not obtained. In Production No. 4 using the metal silicon substrate, the counterbore part and the wettability were poor, and a gap was generated between the bonding layer and the member. Moreover, in these comparative examples, the space | gap concentrated on one side among two counterbore parts, and the location where the joining material oozed out to the through-hole was seen many. The shape accuracy of the inner surface of the through hole could not be obtained at the location where the bleeding occurred.

Schematic which showed the joining method of this invention.

Explanation of symbols

10; joined body 11; first member 11a; counterbore part 111; bottom face 112 of counterbore part; side surface 12 of counterbore part; second member 13a; metal silicon layer 13b before processing; metal silicon layer 14 after processing; G; gap L; bonding layer

Claims (4)

A method of joining a first member made of a silicon carbide sintered body having a counterbore part and a second member made of a silicon carbide sintered body inserted into the counterbore part with metallic silicon,
A melting step in which the silicon silicon is melted in the counterbore part by heating after filling the counterbore part with metal silicon;
After cooling and solidifying the molten metal silicon, a processing step of adjusting the thickness by grinding the metal silicon layer formed in the counterbore part,
A joining step of inserting and heating the second member into the counterbore part;
A method for joining a sintered silicon carbide body. 2. The carbonization according to claim 1, wherein the metal silicon layer after being cooled and solidified before being ground in the processing step is formed in close contact with at least the entire bottom surface and a part of the side surface of the counterbore portion. A method for joining silicon sintered bodies. The joining method according to claim 1 or 2, wherein there are two or more joint portions between the first member and the second member. The joining method according to claim 1, wherein a hollow portion is formed by joining the first member and the second member.

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