JP2007246319A - Ceramic joined body having hollow structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic joined body having a hollow structure excellent in airtightness. <P>SOLUTION: The ceramic joined body having the hollow structure is formed by joining the joining surfaces of ceramic members to each other with a joining layer comprising a ceramic joining material having a melting temperature lower than that of the ceramic members. The joining layer has 0.01-0.2 mm thickness in a direction vertical to the joining surface, a corner part formed from a side wall surface adjacent to one joining surface and a planar surface adjacent to another joining surface is covered with a joining material meniscus having a recessed curved surface and a ratio δ/t of the distance (δ) between the corner part of the side wall surface and the shortest part on the joining material meniscus surface to the thickness (t) of the joining material is ≥0.5 and ≤10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a ceramic joined body having a hollow structure that is suitably used in a semiconductor manufacturing apparatus, a liquid crystal panel manufacturing apparatus, an inspection device, and the like.

Ceramics have the characteristics of light weight, high rigidity, high strength, and high hardness, and also take advantage of their excellent heat resistance and corrosion resistance, especially as structural members, wear resistant members, and corrosion resistant members. It is used in liquid crystal panel manufacturing equipment.
In recent years, with the increase in size and speed of the apparatus, there has been a demand for weight reduction of the member for the apparatus, and as a means for weight reduction, the member is made to have a hollow structure. Further, as a cooling mechanism for a member used at a high temperature, a method of allowing a cooling medium to flow into the hollow structure portion may be taken.
As a method of manufacturing a ceramic member having a hollow structure, there are a method of manufacturing by dividing into a plurality of parts, sealing each part with an O-ring, etc., and mechanically fixing with a bolt or the like, and a method of joining each part. It has been adopted. At this time, in the method of mechanically fixing, the use environment such as temperature is limited, the reliability of the hollow portion of the member is low, and a ceramic joining technique is adopted for a member that requires high airtightness. Often.

Examples of techniques for joining ceramics to obtain a joined body include brazing, diffusion / compression bonding, and sintering.
For example, a method in which a bonded body of a molded body obtained by applying a slurry of the same type as the ceramic molded body to the butted surfaces of the unfired ceramic molded bodies is fired (see, for example, Patent Document 1). Known is a method of applying and bonding glass as a bonding material to the bonding surfaces of ceramic sintered bodies (see, for example, Patent Document 2).
JP-A-2-258205 Japanese Patent Laid-Open No. 5-4876

As a manufacturing method of a ceramic joined body having a hollow structure, when the above-described joining technique is adopted, since ceramic is a brittle material, when heat is applied, defects such as cracks and peeling occur in the joint, There are problems that the wettability of the material is poor and voids are formed in the joint, and that the joint is not completely performed. When a hollow structure ceramic joined body is used in a vacuum, the degree of vacuum decreases due to gas leaking from the hollow structure part or the cooling medium flowing into the hollow structure part flowing out of the hollow structure part. However, contamination of the device is a problem. As described above, while the quality and reliability of the bonded portion of the ceramic bonded member are questioned, the current situation is that attention has not been paid to the shape and structure of the bonded portion so as to improve the airtightness. .

As a result of intensive studies to solve the above problems, the present inventors have achieved excellent airtightness when the shape of the bonding material meniscus adjacent to the bonding layer of the ceramic member has a certain relationship with the bonding layer thickness. As a result, the present invention has been completed.
That is, an object of the present invention is to provide a ceramic joined body having a hollow structure excellent in airtightness.

An object of the present invention described above is a ceramic joined body having a hollow structure in which joining surfaces of ceramic members are joined via a joining layer made of a ceramic joining material having a melting temperature lower than that of the ceramic member, The bonding layer has a thickness t of 0.01 to 0.2 mm in a direction perpendicular to the bonding surface, and is formed of a side wall surface adjacent to one bonding surface and a plane adjacent to the other bonding surface. And the corner delta facing the hollow portion is covered with a concave curved bonding material meniscus, and the distance δ from the corner edge of the side wall surface to the shortest portion on the bonding material meniscus surface, and the bonding layer thickness This is achieved by a ceramic joined body having a hollow structure, wherein the ratio δ / t to t is 0.5 or more and 10 or less.

According to the ceramic joined body of the present invention, the joining material for joining the joining surfaces of the ceramic members has a constant corner corner adjacent to the joining layer in the joining region facing the hollow portion in relation to the joining layer thickness. Since the structure is covered by the shape, the occurrence of defects in the bonded portion is suppressed, and the airtightness of the bonded portion in the ceramic bonded body having a hollow structure can be improved.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
The ceramic joined body 1 of the present invention shown in FIG. 1 has a hollow box structure in which the joining surfaces of ceramic members are joined together via a joining layer made of a ceramic joining material having a melting temperature lower than that of the ceramic member. As shown in FIG. 2, this bonding layer has a thickness t (also referred to as a bonding layer thickness) of 0.01 to 0.20 mm in the direction perpendicular to the bonding surface, and one bonding surface. Formed by a side wall surface adjacent to the other bonding surface and a corner corner facing the hollow portion covered with a concave curved bonding material meniscus, and from the corner edge of the side wall surface to the bonding material The ratio δ / t between the distance δ (also referred to as the meniscus coating distance) to the shortest portion on the meniscus surface and the bonding material thickness t is 0.5 or more and 10 or less.

1A is a perspective view showing a ceramic joined body 1 according to an embodiment of the present invention, as shown in FIG. It is comprised from the member 12 which provided the rib previously by processing, and the joining material 13 which joins these members.

As shown in FIG. 2 in which the portion X in FIG. 1B is enlarged, the bonding material meniscus formed at the corners of the bonding portion has a concave curved surface 13b (also referred to as a bonding material meniscus surface). The bonding material concave curved surface 13b is such that the bonding material 13 has sufficient wettability with the ceramic members 11 and 12, and the side wall surface 12b adjacent to the bonding surface of the rib portion and the bonding surface of the substrate member. It is formed by the contact angle of the bonding material fused with the flat surface 11b becoming an acute angle.

Here, specifically, the contact angle may be smaller than 45 °, and more desirably smaller than 30 °. Thus, by ensuring the wettability between the ceramic member and the bonding material and forming the concave curved bonding material meniscus so as to surround the bonding layer, the above-described defects in the bonding layer are less likely to occur. In addition, even when an internal defect occurs in the bonding layer, there is an effect that the airtightness can be secured by the bonding material meniscus surrounding the bonding layer. Furthermore, sufficient bonding strength can be imparted to the bonded portion by the bonding material meniscus.
Here, the “corner corner facing the hollow portion formed by the side wall surface adjacent to one bonding surface and the plane adjacent to the other bonding surface” is precisely the bonding layer on the side wall surface of the rib portion. The side wall surface of the bonding layer is virtually assumed on the side extension, and is regarded as a corner portion formed by the rib portion adjacent to the bonding surface and the side wall surface of the bonding layer and the substrate plane.

Further, this bonding material meniscus is bonded to the distance δ from the corner edge of the side wall surface adjacent to the bonding surface of one ceramic member, that is, the corner edge 12c of the rib portion to the shortest portion 13c on the bonding material meniscus surface. The ratio δ / t with respect to the layer thickness t is 0.5 or more and 10 or less.
Here, when δ / t is less than 0.5, the bonding material meniscus cannot sufficiently cover the bonding layer and the corner portion adjacent to the bonding layer, which is not preferable because airtightness is lowered. On the other hand, if δ / t is greater than 10, the influence of the difference in thermal expansion between the bonding material and the ceramic member increases, and cracks occur in the bonding material meniscus part or bonding layer, resulting in a decrease in airtightness and bonding strength. Therefore, it is not preferable.

In addition, as shown in FIG.1 (b), although the joining material 13 is formed so that the outer wall side junction part of the ceramic joined body 1 may also be covered, the coating | coated part of an outer wall side junction part is ground and polished as needed. It may be removed by such as. Further, the ratio between the bonding layer thickness t and the meniscus coating distance δ need not be uniform, and may vary within the above range.
Further, the bonding layer 13 shown in FIG. 2 has a thickness t of 0.01 to 0.20 mm in the direction perpendicular to the bonding surface. If the bonding layer thickness t is less than 0.01 mm, the bonding strength will be significantly reduced, so that even if the bonded part is detached or does not come off due to the load during processing or incorporation into the apparatus, Cracks occur and airtightness decreases. On the other hand, when the bonding layer thickness t exceeds 0.20 mm, cracks due to the difference in thermal expansion occur in the bonding material meniscus portion or the bonding layer itself, and the airtightness decreases.

Here, the manufacturing method of the ceramic structure of this invention is demonstrated.
First, a ceramic member processed into a shape according to the purpose such as weight reduction or hollow groove arrangement is produced. As a structure of the ceramic member, in FIG. 1 (a), it is composed of two members, a substrate and a member provided with ribs by processing in advance, but like the ceramic joined body 2 shown in FIG. 3 (a), It is good also as a structure which consists of these three members, the board | substrate 21, the top plate 22 facing the board | substrate 21, the rib 23 arrange | positioned between the board | substrate 21 and the top board 22. FIG. Further, in the structure shown in FIG. 1 and FIG. 3, ribs are provided in the peripheral portion and ribs are also provided in the inside. It may be a structure. Moreover, it is not restricted to a rectangular parallelepiped shape like this example, A various shape is employable if it is a hollow thing. Various structures such as a cylindrical shape, a lattice shape, a honeycomb shape, a pin shape, and a box structure without ribs can be adopted as the hollow structure inside the joined body. Also, the shape of the joined body is not limited to the rectangular parallelepiped shape as shown in FIGS. 1 and 3, and various shapes can be adopted as long as it is hollow.

Here, the surface of the bonding surface of the ceramic member preferably has a flatness of ½ or less of the bonding layer thickness t, a flatness of 10 to 100 μm, and a surface roughness of 0.1 to 0.5 μm.
The reason is that when bonding surfaces having flatness exceeding 1/2 of the bonding layer thickness t are bonded to each other, the maximum distance of the gap between the bonding surfaces may be equal to or greater than the bonding layer thickness. This is because the portion is formed and the airtightness is greatly reduced.

Next, examples of the material of the ceramic member include alumina, yttria, silicon carbide, silicon nitride, sialon, titania, and the like. Although not particularly limited, the same material may be used to prevent poor bonding due to a difference in thermal expansion. Or the thing of materials with a small thermal expansion difference is preferable.

The material of the bonding material is composed of ceramics having a melting temperature lower than that of the ceramic member to be bonded, and is not particularly limited. For example, alumina, silica, magnesia, calcia, etc. In addition, a material in which a plurality of materials are appropriately selected and the composition is adjusted may be used. Moreover, it is preferable that the average particle diameter of a joining material shall be 5.0 micrometers or less. If the average particle diameter is larger than 5.0 μm, the sinterability of the bonding material is deteriorated, an internal defect may be generated in the bonding material, and the airtightness is lowered.
Further, the form of the bonding material is not particularly limited, but it is preferably a paste with a binder and a plasticizer added, and the viscosity of the paste is preferably adjusted to 50 to 300 Pa · sec. As the binder, it is preferable to use polyvinyl alcohol, polyethylene glycol, polyvinyl butyral, polyethylene oxide, polyvinyl acetal, acrylic resin, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, wax emulsion or the like, and plasticizers such as dibutyl phthalate and dimethyl phthalate. It is preferable to use dioctyl adipate. As the solvent, in addition to water and alcohol, organic solvents such as α-terpineol, butyl carbitol, carbitol acetate and the like can be used.

Moreover, it is preferable to adjust the addition amount of a binder, a plasticizer, and a solvent so that the ceramic powder solid content in a joining material may become a ratio of 20 to 60 weight%. When the amount of the ceramic powder used as the bonding material is less than 20% by weight with respect to the entire paste, it causes a void in the bonding layer, and it is difficult to cover the bonding portion with a predetermined thickness with the bonding material meniscus. It becomes. On the other hand, when the amount of the powder exceeds 60% by weight with respect to the entire paste, the viscosity of the paste becomes too high, and the paste cannot be uniformly applied to the joint surface, causing a decrease in joint strength and δ It becomes difficult to set the value of / t to 10 or less.

Next, the bonding material produced as described above is applied so as to have a uniform thickness on the bonding surface of the ceramic member processed into a shape according to the purpose. The method for applying the bonding material is not particularly limited as long as it is a method that can be applied to the bonding surface with a uniform thickness, for example, by printing the bonding material in a paste form using a screen plate. The coating thickness of the bonding material is determined by the solid content of the bonding material, the heat treatment conditions, and the shrinkage rate, and is appropriately adjusted so that the final bonding layer thickness is 0.01 to 0.20 mm.

Next, the bonding of the ceramic member is performed by applying a load to the upper surface of the ceramic member in which the bonding surfaces are bonded together, and heat-treating in a temperature range above the melting temperature of the bonding material and below the melting point of the ceramic member. It is carried out by melt diffusion or sintering. At this time, the heat treatment temperature is preferably about 50 ° C. higher than the melting temperature of the bonding material. When the heat treatment temperature is in the vicinity of the melting temperature, the bonding material has high viscosity and does not have sufficient wettability, so the bonding layer becomes larger than 0.20 mm or the bonding material meniscus becomes a convex curved surface. Cracks are likely to occur, and airtightness cannot be ensured because the structure does not surround the joint as in the case where the joint material meniscus is a concave curved surface. Further, when the temperature is higher by 50 ° C. or more than the melting temperature of the bonding material, the viscosity of the bonding material becomes too low, and the covering distance δ of the bonding material meniscus becomes small, or the thickness of the bonding layer becomes less than 0.01 mm. Further, the bonding layer cannot be sufficiently covered, the airtightness is lowered, and the bonding strength is also insufficient.
Is preferably a load is 5.0~100g / cm ² during the heat treatment, when the load is less than 5.0 g / cm ^2, airtightness decreases becomes poor adhesion of the bonding material, 100 g / cm ^If it exceeds ² , it becomes difficult not only to make the thickness of the bonding layer 0.01 mm or more, but also the ceramic member may be plastically deformed by a load and an unbonded portion may be formed.

The ceramic joined body of the present invention manufactured under such conditions exhibits high airtightness when the joining layer is covered with a joining material meniscus in a predetermined shape without any internal defects in the joining layer. Therefore, the ceramic structure of the present invention is a member for precision equipment such as a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus, a stage member, a table, a guide rail or the like, or a general structural member whose drive source is a servo motor or linear motor. It can be used for stages such as ultrasonic motors, guide materials, jigs, etc., and since the hollow portion in the structure has excellent airtightness, cooling water or He gas can be used as a cooling medium. Etc. can be introduced.

Hereinafter, the present invention will be described in more detail with specific examples and comparative examples of the present invention.
Example 1
(1) Creation of a ceramic joined body As a substrate member (member 1), one alumina sintered body having a shape of 100 mm × 100 mm × 10 mm and a member (member 2) provided with ribs in a shape of 100 mm × 100 mm × 20 mm, One alumina sintered body in which counterbored grooves having a shape of 35 mm × 35 mm × 10 mm were formed by machining so that ribs having a width of 10 mm were arranged in a square shape was produced. The joined surface of each sintered body was subjected to surface grinding to have a flatness of 10 μm and a surface roughness of 0.3 μm.
As a bonding material, alumina, silica, and calcia were used, and a composite powder was prepared by ball mill mixing at a weight ratio of 20:40:40, and then dry pulverized. To this composite powder, 30% by weight of polyvinyl alcohol as a binder and 20% of dibutyl phthalate as a plasticizer were added, and stirred and mixed with a planetary mill mixer to make a bonding material in a paste form.
Next, the bonding material was printed on the bonding surface of the member 1 using a # 100 screen plate, the bonding surfaces were combined, and heat treatment was performed in the air at 1350 ° C. for 3 hours in an electric furnace. In the bonded body, by controlling the printing thickness of the bonding material and the load applied during heat treatment at the distance δ from the corner edge of the side wall surface to the shortest portion on the bonding material meniscus surface and the bonding layer thickness t, t was set to 0.02 to 0.20 mm, and δ / t was set to 0.5 to 10.
Thus, the ceramic joined body which consists of an alumina member which has a hollow structure was created.

(2) Evaluation The measurement of the bonding layer thickness t of the obtained bonded body and the distance δ from the corner edge of the side wall surface to the shortest part on the bonding material meniscus surface is performed by cutting the bonded body perpendicular to the bonded surface. The cross section was observed with an optical microscope.
Moreover, evaluation of the airtightness of the joined body made of the alumina member having the hollow structure was performed by measuring the amount of He leak. The amount of He leak was measured by a bombing method (based on JIS-Z2230) using a He leak detector (manufactured by Nidec Deneru: ASM 151 TURBO). The evaluation results of the leak amount are shown together in Table 1 together with the calculated value of δ / t.
Here, no. In the measured value of the leak amount of 1, 1.2 × 10 ⁻⁶ was abbreviated as 1.2E-6. Similar abbreviations were made for the following measured values of leakage amount.

(Example 2)
As shown in Table 2, yttria, silicon carbide, silicon nitride, and alumina are used as the material of the member constituting the ceramic joined body having a hollow structure, and the same shape as the member 1 and member 2 produced in Example 1 is used. A member was prepared.
A ceramic joined body having a hollow structure was prepared by joining treatments suitable for each material, including an yttria joined body, a silicon carbide joined body, and a silicon nitride joined body in which the members 1 and 2 were made of the same material. Also, an alumina-yttria joined body was produced in which alumina having a thermal expansion coefficient relatively similar to that of yttria was member 1 and yttria was member 2.
As in Example 1, each bonded body has a printing thickness of the bonding material and a load applied during heat treatment at a distance δ from the corner edge of the side wall surface to the shortest portion on the bonding material meniscus surface and the bonding layer thickness t. By controlling, t was set to 0.10 to 0.20 mm, and δ / t was set to 0.5 to 10.
The obtained ceramic joined body having a hollow structure was measured for the amount of He leak by the same method as in Example 1 for evaluation of airtightness. The evaluation results of the leak amount are shown together in Table 2 together with the calculated value of δ / t.

(Comparative Example 1)
A joined body made of an alumina member was produced in the same manner as in Example 1 using alumina as the material of the ceramic joined body having a hollow structure. In the bonded body, by controlling the printing thickness of the bonding material and the load applied during heat treatment at the distance δ from the corner edge of the side wall surface to the shortest portion on the bonding material meniscus surface and the bonding layer thickness t, t was 0.02 to 0.20 mm, and δ / t was 0 to 0.5 and 10 to 20.
The obtained ceramic joined body having a hollow structure was measured for the amount of He leak by the same method as in Example 1 as an evaluation of hermeticity. The evaluation results of the leak amount are shown together in Table 3 together with the calculated value of δ / t.

(Comparative Example 2)
Members having the same shape as the members 1 and 2 produced in Example 1 were produced using yttria, silicon carbide, silicon nitride, and alumina as the material of the ceramic joined body having a hollow structure.
A ceramic joined body having a hollow structure was prepared by joining treatments suitable for each material, including an yttria joined body, a silicon carbide joined body, and a silicon nitride joined body in which the members 1 and 2 were made of the same material. Also, an alumina-yttria joined body was produced in which alumina having a thermal expansion coefficient relatively similar to that of yttria was member 1 and yttria was member 2.
In the bonded body, by controlling the printing thickness of the bonding material and the load applied during heat treatment at the distance δ from the corner edge of the side wall surface to the shortest portion on the bonding material meniscus surface and the bonding layer thickness t, t was set to 0.02 to 0.20 mm, and δ / t was set to 0 to 0.5 and 10 to 15. The obtained ceramic joined body having a hollow structure was measured for the amount of He leak by the same method as in Example 1 for evaluation of airtightness. The evaluation results of the leak amount are shown together in Table 4 together with the calculated value of δ / t.

Here, according to the regulations of JIS, the determination of whether or not the airtightness is acceptable is that a joined body having a He leak amount of 1 × 10 ⁻⁴ atm · cc / sec or more is rejected.
Therefore, according to this regulation, when the pass / fail judgment is made for the ceramic joined bodies of the example and the comparative example, the ratio δ / t between the joining layer thickness t and the covering distance δ of the joining material meniscus is within the scope of the present invention. The ceramic joined bodies of Example 1 and Example 2 were satisfactory because the amount of He leak was 10 ⁻⁶ to 10 ⁻¹⁰ atm · cc / sec and sufficient airtightness.
On the other hand, in Comparative Example 3 and Comparative Example 4 in which δ / t is outside the range of the present invention, the He leak amount is as large as 1 × 10 ⁻⁴ atm · cc / sec, and sufficient airtightness is achieved. It was not obtained and it was unacceptable.

As described above, according to the present invention, a ceramic bonded body having a hollow structure in which bonding surfaces of ceramic members are bonded via a bonding layer made of a ceramic bonding material having a melting temperature lower than that of the ceramic member. The bonding layer has a thickness t of 0.01 to 0.2 mm in a direction perpendicular to the bonding surface, and is formed of a side wall surface adjacent to one bonding surface and a plane adjacent to the other bonding surface. The corner portion facing the hollow portion is covered with a concave curved bonding material meniscus, the distance δ from the corner edge of the side wall surface to the shortest portion on the bonding material meniscus surface, and the bonding layer thickness t By setting the ratio δ / t between 0.5 and 10 inclusive, it was possible to produce a hollow structure ceramic joined body excellent in airtightness.

(A) The perspective view of the ceramic joined body 1 which shows one Example of this invention. (B) AA sectional view. It is an enlarged view of the X section. (A) The perspective view of the ceramic joined body 2 which shows the other Example of this invention. (B) BB sectional drawing.

Explanation of symbols

1, 2: Ceramic bonded bodies 11, 21, 22: Substrate 12: Ribbed member 23: Ribs 13, 24: Bonding material 11a, 12a: Bonding surface 11b: Flat surface portion 12b: Side wall surface 12c: Square edge portion 13a : Bonding layer 13b: bonding material meniscus surface 13c: shortest portion with corner edge

Claims (1)

A ceramic bonded body having a hollow structure in which bonding surfaces of ceramic members are bonded via a bonding layer made of a ceramic bonding material having a melting temperature lower than that of the ceramic member, the bonding layer being perpendicular to the bonding surface The angle facing the hollow portion is formed by a side wall surface adjacent to one joint surface and a plane adjacent to the other joint surface, having a thickness t of 0.01 to 0.2 mm in any direction. The corner δ is covered with a concave curved bonding material meniscus, and the ratio δ / t between the distance δ from the corner edge of the side wall surface to the shortest portion on the bonding material meniscus surface and the bonding layer thickness t is A ceramic joined body having a hollow structure, which is 0.5 to 10 inclusive.

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