JPH072575A - Compound for bonding ceramic and ceramic bonded product - Google Patents

Abstract

PURPOSE:To provide a compound capable of giving ceramic bonded products improved in heat resistance, chemical resistance and adhesivity by mixing (A) prescribed polyhexamethyl cyclosilazane, (B) polymethyl carbosilane, (C) silicon powder and/or SiC powder, and a solvent. CONSTITUTION:Methyl silazane, etc., is polymerized to produce the component A having an average mol.wt. of >=800. Methyl polysilane is decomposition- polymerized to produce the component B which is a precursor of SiC. The component A, the component B and the component C comprising a powdery material having an average particle diameter of 0.2-100mum are compounded with each other at a weight ratio of 1:0.05-0.5:2-20 to provide the compound (D), which is then mixed with a solvent such as xylene in an amount of 0.05-0.5 times weight that of the component D to provide a compound (E) for bonding ceramics. If necessary, ceramic members used as members for treating silicon wafers are bonded with the component E and subsequently heated at >=1000 deg.C to produce the ceramic bonded product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to silicon, silicon carbide (Si
C), silicon nitride, aluminum nitride, non-oxide ceramics such as composites combining these, and various wide range ceramics such as alumina, zirconia, mullite, and other oxide ceramics, and ceramics bonding suitable for filling voids thereof. TECHNICAL FIELD The present invention relates to a compound for ceramics and a ceramic bonded body bonded using the compound, and particularly to a ceramic bonded body bonded to a ceramic member for processing a silicon wafer.

[0002]

2. Description of the Related Art Ceramics have advantages such as high heat resistance and solidity, are chemically inert, and can be prepared with extremely high purity, and are used in various fields as advanced materials. . Generally, the processing of these ceramics is performed at the stage of forming the material before firing. But,
Since a large volume change occurs before and after firing the ceramic molded body, it is difficult to improve the dimensional accuracy only by processing before firing. Therefore, it can be reprocessed to obtain a desired shape and accuracy after firing, but the shape and size of ceramics are limited because they are solid, brittle and poor in workability as described above.

Further, it has been conventionally practiced to form a complex shaped body or a large-sized product by assembling and joining the respective component materials divided so as to form a desired ceramic shaped body. In this case, if the respective ceramic fired component materials cannot be joined in a predetermined shape or the like while maintaining the advantages of ceramics excellent in heat resistance and chemical durability, the original utility value as ceramics is impaired. Therefore, various methods having heat resistance have been carried out as ceramics joining methods. For example, there are a joining method using solder glass and a metal joining method using metallizing. Further, a part of cement-based inorganic material such as alumina cement is also used as a high heat resistant bonding material.

[0004]

However, the materials applicable to both the solder glass bonding method and the metal bonding method are limited, and the heat resistance and the corrosion resistance are not sufficient. Moreover, in addition to requiring advanced technology when joining,
The shape of the joint is also limited to a simple shape. Further, the inorganic material-based bonding material has an advantage that it can be fixed at room temperature, but in order to have fire resistance, it is usually necessary to bake at a high temperature of 1000 ° C. or higher, and the fixing force is remarkably reduced in the baking process, cracks, etc. It was often generated and damaged, and it could only be used for extremely limited materials and applications.
Further, the inorganic material-based bonding material often contains various elemental components as components and impurities, and it may not be possible to achieve a predetermined high degree of purification.

In view of the current state of the above-mentioned conventional method for joining ceramics, the applicant previously disclosed in Japanese Patent Application No. 5-65909 (hereinafter simply referred to as a prior application) a polysilazane compound, a polycarbosilane compound and a ceramic. We proposed a ceramic bonding compound, which is a ceramic bonding material composed of an adhesive solution obtained by dissolving powder in a predetermined solvent. The proposed ceramic bonding compound can firmly bond various ceramics in a simple process, has sufficient bonding strength before and during firing, and has high purity, high heat resistance, high chemical resistance, etc. It is possible to form a superior bonding layer. The present invention, the ceramic bonding compound of the above proposal, to further enhance the practicality, and improve the workability, in particular to obtain a ceramic bonding compound suitable for bonding ceramic members for semiconductor element manufacturing and the like An object of the present invention is to provide a ceramic joined body which has high strength and does not constitute a pollution source in a semiconductor manufacturing process. The present inventors have completed the present invention as a result of further diligent investigations for the respective constituent components of the ceramic bonding compound of the prior application for the above purpose.

[0006]

According to the present invention, (A)
Polyhexamethylcyclosilazane having an average molecular weight of 800 or more, (B) polymethylcarbosilane, and (C) silicon and / or SiC powder are (A) :( B) :( C)
There is provided a compound for joining ceramics, which is characterized by being mixed with a solvent in a weight ratio of 1: 0.05 to 0.5: 2 to 20. Furthermore, after bonding each ceramic member using the above-mentioned ceramic bonding compound,
Provided is a ceramic bonded body, which is characterized by being heat-treated at 1000 ° C. or higher and bonded.

[0007]

The present invention is constituted as described above, and a ceramic bonding compound formed by dissolving a predetermined amount of polyhexamethylcyclosilazane and polymethylcarbosilane and silicon and / or SiC powder in a predetermined amount of a solvent is provided. The ceramic member can be easily fixed by applying it to the joint portion of the ceramic member to be joined and drying it. Furthermore, the fixed state is maintained even during the subsequent heat treatment, and a ceramic bonded body in which the respective members are firmly bonded can be obtained. Moreover, if polyhexamethylcyclosilazane and polymethylcarbosilane are heated in an inert gas or oxygen-containing gas atmosphere, Si
Generates heat-resistant and chemically stable compounds such as N, SiC, SiON, Si, and SiO ₂ and mixes silicon and / or
Alternatively, a solid bonding layer can be formed together with SiC powder to obtain a strong bonded body of ceramic members. In particular,
Since polyhexamethylcyclosilazane having an average molecular weight of 800 or more is used, in the obtained joined body, predetermined joining strength, joining state and the like can be stably obtained, and joining work such as fixing and heating can be easily performed. Furthermore, polyhexamethylcyclosilazane and polymethylcarbosilane can be chemically synthesized, can be easily purified, and do not contain polluting elements harmful to semiconductors such as transition metals and alkali metal ions. , SiN by heating as described above,
Even if SiC, SiON, Si, SiO _{2 and the} like are only produced, and the obtained ceramic joined body is used for the treatment of semiconductor elements, in particular, except for elements such as Si, O, N, C and H, It is extremely reduced and does not become a pollution source.

The present invention will be described in detail below. Polyhexamethylcyclosilazane and polymethylcarbosilane used in the present invention are one type of polysilazane compound and polycarbosilane compound, respectively, and are well known as precursors of silicon carbide (SiC) and silicon nitride (SiN). Has been. The polyhexamethylcyclosilazane of the present invention is a cyclic methylsilazane polymer obtained by polymerizing methylsilazane obtained by, for example, reacting a methylchlorosilane compound with methylamine or the like, and an average molecular weight of 800 or more is used. . Average molecular weight is 80
The bonding compound obtained when it is less than 0 has good adhesiveness, but the amount of volatilization increases in the heat treatment after fixing each member for obtaining the bonded body, and a predetermined strength and the like can be stably obtained. Therefore, the heat treatment conditions must be strictly controlled, which lowers the operability. On the other hand, when the average molecular weight is 800 or more, it is not necessary to strictly control the heat treatment conditions, and it is possible to easily and stably obtain a bonded body having a good bonding state and bonding strength. The polymethylcarbosilane of the present invention is generally represented by the general formula [RR'SiC] obtained by decomposing and polymerizing methylpolysilane.
H ₂ ] n (where R and R ′ are either H or CH ₃ , n = 5 to 5000), which is a compound of the precursor of SiC, and is usually 250 to 350 ° C. under reduced pressure. The low-molecular component which is heated and evaporated by the method is removed by distillation or the like before use.

The ceramic-bonding compound of the present invention comprises the above-mentioned polyhexamethylcyclosilazane compound and polymethylcarbosilane compound, and further silicon and / or SiC powders added and mixed. The particle size of the silicon and SiC powders to be added can be appropriately selected depending on the application means to be applied, the shape of the bonded product, and the like. Also, for filling large gaps, etc., by using powder with a large particle size,
Less shrinkage after drying and good results can be obtained.
However, when powder such as silicon with a large particle size is used,
When the obtained bonding compound is stored, the powder such as silicon may be easily settled and separated. Therefore, it is usually preferable to use powder having an average particle size of 0.2 to 100 μm. A powder of silicon or the like having an average particle diameter within this range is suitable because it has good coatability and is easy to handle. Other ceramic powders may be partially replaced and added to the silicon and / or SiC powder of the present invention. In particular, it is preferable to select and add from other ceramic components constituting each member to be joined.

In the ceramic bonding compound of the present invention, the polyhexamethylcyclosilazane compound, the polymethylcarbosilane compound and the silicon and / or SiC powder are added and mixed at a mixing ratio of 1 to the polyhexamethylcyclosilazane compound. Polymethylcarbosilane compound is 0.05 to 0.5 times by weight, silicon and / or
Alternatively, the SiC powder is blended in an amount of 2 to 20 times. The mixing ratio of the polymethylcarbosilane compound is 0.05 with respect to the above polyhexamethylcyclosilazane compound 1.
If it is less than 0.5, the high temperature strength is not sufficient, and if it exceeds 0.5, the strength after heat cycle is greatly reduced, which causes a problem. Further, if the content of silicon and / or SiC powder is less than 2 with respect to the polyhexamethylcyclosilazane compound 1, the effect of preventing cracks during firing is not sufficient, and if it exceeds 20, the bonding strength decreases and it is not practical. .

The compound of the present invention is usually prepared by adding a powder mixture obtained by blending the above-mentioned polyhexamethylcyclosilazane compound and polymethylcarbosilane compound and silicon and / or SiC powder in a predetermined amount to a solvent, and then thoroughly adding It can be obtained by kneading. The solvent of the present invention is
It is preferable to use one that can dissolve both the polyhexamethylcyclosilazane compound and the polymethylcarbosilane compound, and an organic solvent such as xylene, toluene or cyclohexane can be usually used. Further, the mixing ratio of the solid content of the powder mixture and the solvent can be appropriately selected according to each condition at the time of bonding. These are related to workability such as coating, and generally, the higher the boiling point of the solvent and the smaller the amount, the shorter the drying time and the smaller the volume after drying, and the better results can be obtained. However, if the amount of the solvent is too small, the fluidity is lowered and the coating work becomes difficult. Therefore, the powder mixture and the solvent are 1: 0.0
It is preferable to mix in a weight ratio of 5 to 0.5. In order to impart high fluidity, the liquid component of the solvent is 20% by weight.
Mix and add as described above. In the present invention, for the purpose of improving workability, an appropriate amount of a surfactant or a thickener may be added in addition to the above powder mixture and solvent.

The ceramic bonding compound of the present invention obtained as described above uses a brush, a dispenser or the like, and is made of, for example, silicon, SiC or silicon-impregnated Si.
The joint portion can be formed by applying or pouring a certain amount on the joint surface of each ceramic member to be joined which is processed into a desired shape such as a semiconductor element manufacturing member using C or the like as a material. After the coating and the like, before the solvent evaporates and solidifies, the joint portions of the respective ceramic members to be joined are butted and heated and dried if necessary. Furthermore, thereafter, in an atmosphere of an inert gas such as nitrogen or argon, or in an atmosphere of an oxygen-containing gas such as air, the temperature is 300 ° C. or higher, preferably 1000 ° C. or higher.
By subjecting to a heat treatment at a temperature of not lower than 0 ° C., it is possible to obtain a desired ceramic joined body having high heat resistance and high strength joining.

In the present invention, by the combined use of both the polysilazane compound, polyhexamethylcyclosilazane, and the polycarbosilane compound, polymethylcarbosilane, a joint having a predetermined high strength over the entire application temperature range is obtained. Can be held, and by mixing silicon and / SiC powder, volume shrinkage can be prevented regardless of the size of the joint surface, and gaps and cracks at the joint can be prevented, making it stable and good. It is possible to obtain a good joint portion and improve the joint strength. Therefore,
For example, if a semiconductor boat manufacturing member such as a wafer boat is damaged during processing, the debris contaminates the device.
It is necessary to impart high strength of MPa or more to prevent damage, and the temperature history from room temperature to a high temperature of 1000 ° C. or more is complicatedly repeated during use, and strength does not decrease even in such a usage mode. Although required to have durability, the ceramic bonding compound of the present invention can provide a ceramic bonded body having a bonding portion having a bonding strength that can sufficiently satisfy these requirements. At the same time, the bonded portion of the ceramic bonded body of the present invention is extremely smooth and dense, has excellent water repellency, and produces contaminants even when applied to a member for manufacturing a semiconductor element or the like. Never.

[0014]

EXAMPLES The present invention will now be described in detail based on examples. However, the present invention is not limited to the following examples. Examples 1 to 4 and Comparative Examples 1 to 3 Polyhexamethylcyclosilazane 1 having an average molecular weight of 900
On the other hand, polymethylcarbosilane was mixed at each weight ratio shown in Table 1, and further, silicon powder having an average particle size of 20 μm was added and mixed at a weight ratio of 1: 5 with the above mixture to give polyhexahexa. A mixed powder composed of methylcyclosilazane, polymethylcarbosilane and silicon was obtained. Furthermore,
Xylene was added to the obtained mixed powder solid content in a weight ratio of 1: 0.5, and the mixture was kneaded with a ball mill for 4 hours to prepare bonding compounds. The bonding compounds thus prepared were each about 30 g.

Also, the diameter of the end face is 10 mm and the surface is finished.
A silicon rod having φ and a length of 30 mm was prepared. Next, each bonding compound obtained above was applied to the end face of one silicon rod by a quartz glass rod to form a joint, and then the end faces of the other silicon rods were joined together and pressed and bonded. The bonded silicon bonded body was dried at 70 ° C. for 3 hours to fix the bonded portion. Then, the adhered silicon bonded body was fired at each temperature shown in Table 1 in an argon gas atmosphere. Each initial tensile strength (X) of the fired and formed silicon bonded body was measured. The results are shown in Table 1. Further, after heating each silicon bonded body to 1000 ° C. in the furnace, taking out from the furnace to the room and rapidly cooling it, the thermal cycle was repeated 10 times, and then the tensile strength (Y) of each silicon bonded body after the thermal cycle was measured. did. The results are shown in Table 1. From the above Examples and Comparative Examples, polyhexamethylcyclosilazane 1
On the other hand, when polymethylcarbosilane is used with a bonding compound having a polymerization ratio of 0.05 to 0.5 and the heat treatment temperature is 1000 ° C. or higher, the initial tensile strength of the obtained ceramic bonded body is 100 MPa or higher, There is little decrease in tensile strength after thermal cycling. On the other hand, when the weight ratio of polymethylcarbosilane is less than 0.05 or more than 0.5, the initial tensile strength is lower than 100 MPa and the initial tensile strength is 100 MPa, but It can be seen that the decrease is remarkable.

[0016]

[Table 1]

Examples 5 to 18 and Comparative Examples 4 to 7 To the hexamethylcyclosilazane 1 used in Example 1, the polymethylcarbosilane used in Example 1 was added to 0.1%.
2 in a weight ratio of 0.5 to 100.
Silicon powder having an average particle size of 20 μm in μm and / or S having an average particle size of 15 μm in a particle size distribution of 0.5 to 80 μm
The iC powder was added to hexamethylcyclosilazane 1 at the weight ratio shown in Table 2 to obtain a mixed powder. Cyclohexane of the same weight as the solid content of the obtained mixed powder was added, and well kneaded with a ball mill to prepare a bonding compound. Using SiC rods having the same shape as in Example 1, and using the obtained bonding compounds, two SiC rods were end-face joined in the same manner as in Example 1. Then 100 ℃
After being dried in, a heat treatment was performed at 1000 ° C. in a nitrogen gas atmosphere to obtain a SiC joined body. For each of the obtained SiC joined bodies, each initial tensile strength (X) and tensile strength after thermal cycle (Y) were measured in the same manner as in Example 1.
The results are shown in Table 2. Further, the appearance of the bonded portion of the obtained SiC bonded body was enlarged and observed with a microscope. The result is
The appearance is shown in Table 2. As is clear from the above Examples and Comparative Examples, when the addition weight ratio of the silicon powder and the SiC powder is less than 2 or more than 20 relative to polyhexamethylcyclosilazane, the initial strength is 100 MPa.
It is below, and it can be seen that the appearance is not good.

[0018]

[Table 2]

EXAMPLE 19 4 g of hexamethylcyclosilazane used in Example 1, 1.2 g of polymethylcarbosilane used in Example 1 and 16 g of silicon powder having an average particle size of 10 μm were mixed with xylene 6
and kneaded well with g to prepare a bonding compound. Using the bonding compound thus prepared, a silicon wafer heat treatment boat (silicon bonding structure) having a structure as shown in FIG. 1 was assembled. Here, the end portion 3 of the prismatic silicon member 1 with a groove to be joined to the silicon plate 2 is processed into a worm shape as shown in FIG. The above-described bonding compound was applied to this end portion 3 and fitted into the hole portion 4 of the silicon plate 2 before drying. After assembly, it was dried at 1000 ° C. and then heat-treated to 1200 ° C. in an argon gas atmosphere. The wafer was mounted on the obtained wafer heat treatment boat and heat-treated in oxygen at 1000 ° C. for 30 minutes to oxidize the surface. The oxide film was washed with hydrofluoric acid to dissolve the oxide film, and the impurity concentration was analyzed. On the other hand, for comparison, a boat made of high-purity quartz glass was used to perform the wafer oxidation treatment in the same manner, and the purity of the oxide film was analyzed. as a result,
In both, the concentration of Al, Fe, Na, Ca is 1 × 10
^The purity was ¹⁵ atoms / cm ³ or less.

[0020]

EFFECTS OF THE INVENTION The present invention is constructed as described above and is used for joining ceramics formed by dissolving a predetermined amount of polyhexamethylcyclosilazane and polymethylcarbosilane and silicon and / or SiC powder in a predetermined amount of solvent. The compound is a high-purity ceramic
It is possible to form a bonded portion having excellent high heat resistance, high chemical resistance, etc., and easily and stably obtain a ceramic bonded body in which the respective members are firmly bonded. Further, the ceramic bonding compound and the ceramic bonded body of the present invention are made of polyhexamethylcyclosilazane and polymethylcarbosilane compounds mainly composed of Si, O, N, C and H elements, in addition to the ceramic powder. Since it is used as a constituent component, it does not constitute a semiconductor pollution source and is also useful as a bonding material or filler for various ceramic members in the semiconductor element manufacturing process.

[Brief description of drawings]

FIG. 1 is a perspective view showing the appearance of a wafer heat treatment boat prepared in an example of the present invention.

FIG. 2 is an enlarged perspective view showing a structure of a joint end portion of the wafer heat treatment boat.

[Explanation of symbols]

 1 prismatic silicon member with groove 2 silicon plate 3 end 4 hole

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[Procedure amendment]

[Submission date] January 19, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

Claims (3)

[Claims] 1. (A) polyhexamethylcyclosilazane having an average molecular weight of 800 or more, (B) polymethylcarbosilane, and (C) silicon and / or SiC powder,
(A) :( B) :( C) = 1: 0.05 to 0.5: 2
A compound for bonding ceramics, characterized by being mixed with a solvent in a weight ratio of 20. 2. After bonding each ceramic member using the ceramic bonding compound according to claim 1, 10
A ceramic bonded body, characterized by being heat-treated at a temperature of 00 ° C. or higher and bonded. 3. The ceramic joined body according to claim 2, wherein the ceramic member is a member for processing a silicon wafer.