JP2007246321A - Low thermal expansion ceramic joined body having hollow structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low thermal expansion ceramic joined body having hollow structure excellent airtightness in which the joining defect of low thermal expansion ceramic members is eliminated. <P>SOLUTION: The low thermal expansion ceramic joined body having the hollow structure is formed by joining the joining surfaces of the low thermal expansion ceramic members to each other with a joining layer comprising a low thermal expansion ceramic joining material having a melting temperature lower than that of the ceramic members. The joining layer has 5-60 μm thickness (t) 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 and facing the hollow part 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 ≤5.0. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a low thermal expansion 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.

In recent years, semiconductor circuits have been increasingly refined, and even a slight deformation of the manufacturing apparatus causes a decrease in yield. Therefore, low thermal expansion ceramics with low thermal expansion and high rigidity are used as members for semiconductor manufacturing apparatus. . Furthermore, in response to demands for weight reduction of equipment members due to equipment enlargement and high-speed movement, it is necessary to construct a hollow structure in which the inner part is configured with ribs, honeycombs, etc., and the thick part is reduced without greatly impairing rigidity. In fact, such a structure is also adopted in the low thermal expansion ceramic member.

When manufacturing a ceramic member having a hollow structure, since it is difficult to process with a single member, a method of manufacturing a plurality of parts and finally joining each part is used. As a low thermal expansion ceramic member having such a hollow structure, a low thermal expansion ceramic joined body in which a member made of low thermal expansion ceramic is joined with a joining material made of low thermal expansion ceramic having a melting temperature lower than that of the member has been proposed. (For example, refer to Patent Document 1.)
Further, there is provided an exposure apparatus stage member formed by joining a thermal expansion ceramic bottom plate material and an upper plate material of the same material having a groove communicating from one end to one end with a bonding material made of low thermal expansion ceramic having a melting temperature lower than that of the plate material. It has been proposed that it is possible to cool the stage by flowing water or air as a cooling medium in the groove. (For example, see Patent Document 2.)
Furthermore, a stage member for an exposure apparatus has been proposed in which ceramic plates are joined to the top and bottom of a honeycomb structure ceramic body. (For example, refer to Patent Document 3.) When such a stage member is used in a vacuum apparatus, a pressure difference is generated between the inside and outside of the honeycomb hollow structure, so that the airtightness of the honeycomb structure can be maintained to withstand the pressure. The outer peripheral part is designed to be thick and the stage has mechanical strength.
JP 2004-59402 A JP 2004-179353 A JP 2005-164878 A

However, in actuality, it is difficult to completely maintain the airtightness of the hollow portion in the joining of the ceramic members having a hollow structure. When water or air is allowed to flow as a cooling medium in the groove portion of the stage member, cooling is not possible. When the medium leaks out of the groove from the minute gap in the joint, or when used in a vacuum device, the gas leaks from the joint even if the outer periphery of the hollow structure is thickened, and the degree of vacuum The yield of the product was bad and became a big problem.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention are excellent when the shape of the bonding material meniscus adjacent to the bonding layer of the low thermal expansion ceramic bonded body has a certain relationship with the bonding layer thickness. As a result, the present invention was completed.
That is, an object of the present invention is to provide a low thermal expansion ceramic joined body having a hollow structure that is excellent in airtightness and eliminates such poor bonding of the low thermal expansion ceramic joined body.

An object of the present invention described above is to provide a low thermal expansion ceramic joint having a hollow structure in which joining surfaces of low thermal expansion ceramic members are joined via a joining layer made of a low thermal expansion ceramic joining material having a melting temperature lower than that of the member. The bonding layer has a thickness t of 5 to 60 μm 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 a corner delta facing the hollow portion is covered with a concave curved bonding material meniscus, and a distance δ from the corner edge of the side wall surface to the shortest portion on the bonding material meniscus surface, and a bonding layer The ratio δ / t to the thickness t is 0.5 or more and 5.0 or less, and this is achieved by a low thermal expansion ceramic joined body having a hollow structure.

According to the low thermal expansion ceramic joined body of the present invention, the joining material for joining the joining surfaces of the low thermal expansion ceramic members has a corner portion adjacent to the joining layer in the joining region facing the hollow portion. Since the structure is covered with a certain shape, the occurrence of defects in the joint is suppressed, and the air tightness of the joint in the low thermal expansion ceramic joined body having a hollow structure can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A low thermal expansion ceramic joined body 1 of the present invention shown in FIG. 1 is formed by joining the joining surfaces of low thermal expansion ceramic members via a joining layer made of a low thermal expansion ceramic joining material having a melting temperature lower than that of the member. As shown in FIG. 2, this bonding layer has a thickness t (also referred to as a bonding layer thickness) of 5 to 60 μm in the direction perpendicular to the bonding surface, as shown in FIG. The corner corner formed by the side wall surface adjacent to one joint surface and the plane adjacent to the other joint surface is covered with a concave curved joint material meniscus, and from the corner edge of the side wall surface The ratio δ / t between the distance δ (also referred to as the meniscus coating distance) to the shortest portion on the bonding material meniscus surface and the bonding layer thickness t is 0.5 or more and 5.0 or less.

FIG. 1A is a perspective view showing a low thermal expansion ceramic joined body 1 according to an embodiment of the present invention. As shown in FIG. And a ceramic member 12 previously provided with ribs by processing, and a bonding material 13 for bonding 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, the contact angle may specifically be smaller than 40 °, and more desirably smaller than 25 °. 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, airtightness can be ensured 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. Assuming the side wall surface of the bonding layer on the side extension, it 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 to the material thickness t is 0.5 or more and 5.0 or less. When δ / t is less than 0.5, the bonding material meniscus cannot sufficiently cover the bonding layer and the corners adjacent to the bonding layer, and the airtightness is lowered. Conversely, the airtightness also decreases when δ / t is greater than 5.0. The case where δ / t increases beyond 5.0 is when the bonding material is excessively melted, t decreases, and the portion that exudes from the bonding layer increases. As will be described later, the low thermal expansion ceramic of the bonding material is a composite material of a first material exhibiting a negative thermal expansion and a second material exhibiting a positive thermal expansion. It is exhibited by a stress relaxation mechanism caused by microcracks in the grain boundary phase. However, when the particles are heated and melted excessively and grain growth proceeds, microcracks expand and large cracks are generated, resulting in a decrease in hermeticity.

As shown in FIG. 1B, the bonding layer 13 is formed so as to cover the outer wall side bonded portion of the low thermal expansion ceramic bonded body 1 as well, but the coated portion of the outer wall side bonded portion is ground if necessary. It may be removed by polishing or the like. 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.

Furthermore, the bonding layer 13 shown in FIG. 2 has a thickness t of 5 to 60 μm in the direction perpendicular to the bonding surface. If the bonding layer thickness t is less than 5 μm, the bonding strength will be significantly reduced, so even if the bonding part is detached or does not come off due to a load during processing or incorporation into the apparatus, cracks are generated inside. Resulting in reduced airtightness. Further, the airtightness is also lowered when the bonding layer thickness t exceeds 60 μm. When t exceeds 60 μm, it is a case where the bonding material is insufficiently melted, and leakage occurs through pores in the bonding layer.

Here, it is preferable that the average coefficient of thermal expansion of the member and the bonding material at 20 to 30 ° C. is −1 × 10 ⁻⁶ to 1 × 10 ⁻⁶ / ° C. Within this range, when used as a semiconductor manufacturing apparatus member, it can be adapted to refinement of a semiconductor circuit. Moreover, it is preferable that the difference of the average thermal expansion coefficient in 20-30 degreeC between a member and a joining material is less than +/- 0.1x10 < ^-6 > / ^degreeC . If the difference in thermal expansion coefficient exceeds this range, after heat treatment for bonding, cracks may occur due to internal stress in the cooling process, leading to a decrease in hermeticity.

The low thermal expansion ceramic constituting the bonding material is preferably a composite material composed of two or more kinds of materials. Thus, by using a composite material as the low thermal expansion ceramic constituting the bonding material, the composition of the constituent materials can be changed so as to achieve thermal expansion suitable for the low thermal expansion ceramic member, and the degree of freedom of application is extremely high. can do.

The composite material constituting the bonding material includes one or more first materials selected from lithium aluminosilicate and cordierite, silicon carbide, silicon nitride, sialon, alumina, zirconia, mullite, zircon, aluminum nitride, silicon nitride. What consists of 1 or more types of 2nd materials chosen from calcium acid is suitable. Of these constituent materials, the first material has a very low thermal expansion, and the second material has a higher coefficient of thermal expansion than the first material, but has a higher Young's modulus. And it can be set as the material which has high rigidity.

As the first material, lithium aluminosilicate β-eucryptite and spodumene are preferable. Of these, β-eucryptite exhibits a negative thermal expansion, so that it can be combined with a second material exhibiting a positive thermal expansion to obtain an extremely low thermal expansion coefficient. It is possible to adjust the thermal expansion coefficient in a wide range from minus to plus by adjusting. In addition, although lithium aluminosilicate represented by β-eucryptite and spodumene forms a solid solution with other components such as Ca, Mg, Fe, K, Ti, and Zn, such a solid solution is also applied in the present invention. Is possible.
On the other hand, the second material is appropriately selected from the above materials so that the melting temperature of the bonding material is lower than the melting temperature of the low thermal expansion ceramic member.

Specifically, the composite material constituting the bonding material is preferably a material composed of β-eucryptite and silicon nitride. This composite material has low thermal expansion, high rigidity, and a relatively low melting temperature of 1300 to 1360 ° C. In the present invention, since the bonding material can bond a low thermal expansion ceramic member that is sintered at a temperature higher than its melting temperature, such a bonding material that melts at a relatively low temperature has a wide range of applications. In addition, as described above, β-eucryptite has a negative thermal expansion coefficient, and silicon nitride has a positive thermal expansion coefficient. Therefore, by changing the mixing ratio of these, the negative expansion can be changed to the positive expansion. Thus, it is possible to arbitrarily change the thermal expansion coefficient. Therefore, by appropriately selecting the mixing ratio according to the thermal expansion coefficient of the ceramic member, any material member can apply stress to the joint. Good bonding can be achieved without causing it.

Moreover, it is preferable that not only the bonding material but also the ceramic member and the bonding material are both made of a low thermal expansion ceramic made of a composite material made of two or more kinds of materials. Thus, by using a composite material for both, if the blending ratio of the material constituting the ceramic member is changed, it is possible to cope with various required thermal expansions, and the bonding material is applied to the ceramic member. Since the composition of the constituent materials can be changed so as to achieve suitable thermal expansion, it is possible to easily obtain a low thermal expansion ceramic bonded body having desired characteristics, and it is possible to apply with a high degree of freedom.

In this case, as the composite material constituting the ceramic member and the bonding material, the above-described one or more first materials selected from lithium aluminosilicate and cordierite, silicon carbide, silicon nitride, sialon, alumina, A material composed of one or more second materials selected from zirconia, mullite, zircon, aluminum nitride, and calcium silicate is preferable. Similarly, the first material is preferably lithium aluminosilicate β-eucryptite or spodumene, and β-eucryptite is particularly preferable. As lithium aluminosilicate, what dissolved the above other elements can be used. On the other hand, the second material constituting the bonding material and the ceramic member is appropriately selected from the above materials so that the melting temperature of the bonding material is lower than the melting temperature of the ceramic member.

In the composite material constituting the bonding material and the ceramic member, a plurality of materials may be used in combination as the first material if no substantial chemical reaction occurs. Similarly, the second material can be used in combination with a plurality of materials as long as no substantial chemical reaction occurs.
When both the ceramic member and the bonding material are composite materials, it is preferable that at least one of the constituent materials of the composite material constituting the ceramic member is the same as the constituent material of the composite material constituting the bonding material. As a result, the common constituent material can be easily diffused and firmly bonded, and the bonding surface is clean.

When the ceramic member and the bonding material are both composite materials, the specific material combination is arbitrary as long as the melting temperature of the bonding material is lower than the melting temperature of the ceramic member, and various combinations are adopted. can do. Among them, a ceramic member using a composite material of β-eucryptite and silicon carbide and a composite material of β-eucryptite and silicon nitride as a bonding material is preferable. A ceramic member made of a composite material of β-eucryptite and silicon carbide has a melting temperature of 1370 to 1430 ° C. and 1300 which is the melting temperature of the composite material of β-eucryptite and silicon nitride constituting the bonding material. It is higher than ˜1360 ° C., and there is no possibility of melting the ceramic member when the bonding material is melted and bonded. Moreover, since β-eucryptite is commonly contained in the ceramic member and the bonding material, the bonding is strong, and both of these have low thermal expansion, and by adjusting the composition, almost the same thermal expansion coefficient is obtained. In addition, both the ceramic member and the bonding material have high rigidity. In this case, the composition of the ceramic member is β-eucryptite 50 to 95% by weight and silicon carbide 5 to 50% by weight, and the composition of the bonding material is β-eucryptite 40 to 85% by weight and silicon nitride. It is preferably 15 to 60% by weight.

Here, the manufacturing method of the low thermal expansion ceramic joined body of this invention is demonstrated.
First, a low thermal expansion ceramic member processed into a shape according to the purpose such as weight reduction or hollow groove arrangement is produced. In FIG. 1A, the member is composed of two members: a substrate and a member provided with ribs by processing in advance. However, like the joined body 2 shown in FIG. The top plate 22 facing the substrate 21, the ribs 23 disposed between the substrate 21 and the top plate 22, and the three members may be used. 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. 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. 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, thereby forming an unbonded portion. The airtightness is greatly reduced.

In the joined body of the present invention, the bonding material powder is kneaded together with an appropriate binder, plasticizer and solvent to form a paste having a sticky property, and the ceramic members are bonded to each other through the paste, and organic components such as the binder are burned off. Then, heat treatment is performed at a temperature at which the bonding material melts but the ceramic member does not melt. As a result, the bonding material is melted and part of the bonding material is diffused into the ceramic member to bond the members together.
As the heat treatment atmosphere in this case, an air atmosphere can be used if the material is all oxide-based, but if a non-oxide-based material is included, a non-oxidizing atmosphere should be used. preferable. The average particle diameter of the bonding material is preferably 2.0 μm or less. If the average particle diameter exceeds 2.0 μm, the sinterability of the bonding material is deteriorated, and internal defects may be generated in the bonding material, resulting in a decrease in airtightness.

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 0.5 or more.

Next, the bonding material manufactured as described above is applied so as to have a uniform thickness on the bonding surface of the low thermal expansion 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 5 to 60 μm.

Next, the ceramic member is bonded by applying a load to the upper surface of the ceramic member obtained by bonding the bonding surfaces together. Is preferably a load is 5.0~100g / cm ^2, when the load is less than 5.0 g / cm ^2, airtightness decreases becomes poor adhesion of the bonding material, greater than 100 g / cm ² In addition, it is difficult to make the thickness of the bonding material 60 μm or less, and there is a possibility that the ceramic member is plastically deformed by a load and an unbonded portion is formed.
After the ceramic members are bonded to each other via a bonding material, heat treatment is performed in a temperature range not lower than the melting temperature of the bonding material and not higher than the melting point of the ceramic member. For example, when a composite material of β-eucryptite and silicon carbide is used as the ceramic member and a composite material of β-eucryptite and silicon nitride is used as the bonding material, β-eucryptite and silicon carbide The ceramic member made of this composite material has a melting temperature of 1370 to 1430 ° C., and the melting temperature of the composite material of β-eucryptite and silicon nitride constituting the bonding material is 1300 to 1360 ° C. Can be joined without melting. In the vicinity of the melting temperature, since the bonding material has a high viscosity and does not have sufficient wettability, the bonding layer becomes larger than 60 μm or the bonding material meniscus becomes a convex curved surface, so that cracks are likely to occur. Since the joining material meniscus does not have a structure surrounding the joint as in the case of a concave curved surface, airtightness cannot be ensured. If the heat treatment temperature for bonding is too high, the viscosity of the bonding material becomes too low, the bonding distance δ of the bonding material meniscus becomes smaller, the bonding layer becomes less than 5 μm, and the bonding layer is sufficiently covered. The airtightness is lowered and the bonding strength is insufficient.

The low thermal expansion ceramic bonded body of the present invention manufactured under such conditions exhibits high airtightness when the bonding layer has no internal defect and the bonding portion is covered with the bonding material meniscus in a predetermined shape. . Therefore, the low thermal expansion ceramic joined body 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. It can be used for stages such as linear motors, ultrasonic motors, guide materials, jigs, etc., and the hollow part in the structure has excellent airtightness. He gas or the like can be introduced.

Hereinafter, the present invention will be described in more detail with specific examples and comparative examples of the present invention.
(Examples 1-20)
(1) Preparation of ceramic joined body First, β-eucryptite powder and silicon carbide powder were mixed in a pot mill at a ratio shown in Table 1 and dried to prepare a base ceramic mixed powder. This mixed powder was uniaxially pressed to produce a molded body, which was CIP treated at 150 MPa. Firing was performed at 1400 ° C. in a nitrogen atmosphere to obtain a low thermal expansion ceramic sintered body made of a base ceramic material. The shape of the sintered body is a shape of 35 mm × 35 mm so that one plate member (substrate) of 100 mm × 100 mm × 10 mm is formed in a shape of 100 mm × 100 mm × 20 mm, and a rib of 10 mm in width is arranged in a rice field. One ceramic member provided with ribs provided with × 10 mm counterbored grooves by machining was produced. The joined surface of each ceramic member was subjected to surface grinding to have a flatness of 10 μm and a surface roughness of 0.3 μm. The thermal expansion coefficient was measured by cutting a 4 mm × 4 mm × 12 mm test piece from the sintered body and using a laser interference thermal expansion measuring device (LIX-1 manufactured by ULVAC-RIKO) at 20-30 ° C. Was measured and the coefficient of thermal expansion was determined.
Next, β-eucryptite and silicon nitride were mixed in a pot mill at a ratio shown in Table 1 and dried to prepare a mixed powder for a bonding material. The mixed powder was mixed with a 15% α-terpineol solution of ethyl cellulose as a binder and dibutyl phthalate as a plasticizer so that the inorganic content was 30 vol%, and formed into a paste using a three roll. In addition, the thermal expansion coefficient was calculated | required similarly to the ceramic member which produced the sintered compact of the same composition about this joining material and provided the plate-shaped member and the rib. The results are also summarized in Table 1. Both the base material ceramics and the bonding material were low thermal expansion ceramics.

The obtained paste-like bonding material was printed on the bonding surface of the ceramic member to which the plate-shaped member and the rib were provided using a # 100 screen mask. After degreasing at 500 ° C., the printed surfaces of the members were bonded together. Subsequently, heat treatment was performed at a temperature shown in Table 1 in a nitrogen atmosphere, and the bonding material was melted to obtain a low thermal expansion ceramic bonded body having a hollow structure in which the bonding material was interposed between the base ceramic materials. At this time, the melting temperature of the base material ceramics is higher than the temperature at which the bonding material melts, so the base material ceramics were not melted at the bonding temperature. In addition, for the distance δ from the corner edge of the side wall surface of the joined body to the shortest part on the joining material meniscus surface, the joining material thickness t, by controlling the printing thickness of the joining material and the load applied during heat treatment, t was 6 to 53 μm, and δ / t was 0.5 to 5.0.

(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.
Further, the evaluation of the airtightness of the obtained ceramic joined body 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 2 together with the calculated value of δ / t.
Here, in the table, 1.2 × 10 ⁻⁶ was abbreviated as 1.2E-6 in the measured value of the leak amount of Example 1. Similar abbreviations were made for the following measured values of leakage amount.

(Comparative Examples 1-20)
The material and shape of the low thermal expansion ceramic member constituting the low expansion ceramic joined body having a hollow structure were the same as in the example.
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 to 5 to 51 μm and δ / t to 0 to 0.4 and 5.4 to 9.9.
The obtained low-expansion ceramic joined body having a hollow structure was measured for the amount of He leak by the same method as in the examples as an evaluation of airtightness. The evaluation results of the leak amount are shown together in Table 3 together with the calculated value of δ / t.

Here, according to the regulations of JIS, the judgment of pass / fail of the airtightness of the ceramic joined body is rejected for a joined body having a He leak amount of 1 × 10 ⁻⁴ atm · cc / sec or more.
Therefore, according to this rule, when the pass / fail judgment is evaluated 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 range of the present invention. In the ceramic joined bodies of Examples 1 to 20, the He leak amount is 10 ⁻⁶ to 10 ⁻¹⁰ atm · cc / sec and has sufficient airtightness, whereas δ / t is In Comparative Examples 1 to 20, which are out of the scope of the invention, the amount of He leak was 1 × 10 ⁻⁴ atm · cc / sec or more, and it was found that sufficient airtightness was not obtained and was rejected.

As described above, according to the present invention, the bonding surfaces of the low thermal expansion ceramic members have a hollow structure formed by bonding via a bonding layer made of a low thermal expansion ceramic bonding material having a melting temperature lower than that of the members. In the low thermal expansion ceramic bonded body, the bonding layer has a thickness t of 5 to 60 μm in a direction perpendicular to the bonding surface, and is adjacent to the side wall surface adjacent to one bonding surface and the other bonding surface. The corners facing the hollow portion formed by a flat surface are covered with a concave curved bonding material meniscus, and the distance δ from the corner edge of the side wall surface to the nearest part on the bonding material meniscus and the bonding material thickness By setting the ratio δ / t to t to be not less than 0.5 and not more than 5.0, a hollow structure low thermal expansion ceramic joined body having excellent airtightness could be produced.

(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

DESCRIPTION OF SYMBOLS 1, 2: Low thermal expansion ceramic joined body 11, 21, 22: Board | substrate 12: Ceramic member 23 which provided the rib 23: Rib 13, 24: Joining material 11a, 12a: Joining surface 11b: Planar part 12b: Side wall surface 12c: Corner Edge 13a: Bonding layer 13b: Bonding material meniscus surface 13c: Shortest portion with corner edge

Claims (2)

A low thermal expansion ceramic joined body having a hollow structure in which bonding surfaces of a low thermal expansion ceramic member are joined via a joining layer made of a low thermal expansion ceramic joining material having a melting temperature lower than that of the member, the joining layer Has a thickness t of 5 to 60 μm in a direction perpendicular to the joint surface, and faces a hollow portion formed by a side wall surface adjacent to one joint surface and a plane adjacent to the other joint surface. 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, where the corner is covered with a concave curved bonding material meniscus Is a low thermal expansion ceramic joined body having a hollow structure characterized by being 0.5 or more and 5.0 or less. 2. The hollow structure according to claim 1, wherein an average thermal expansion coefficient of the low thermal expansion ceramic member and the bonding material at 20 to 30 ° C. is −1 × 10 ⁻⁶ to 1 × 10 ⁻⁶ / ° C. 3. A low thermal expansion ceramic joined body having:

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