JPH0324431B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a ceramic bonding agent suitable for bonding objects made of ceramics and a method of bonding ceramics, and in particular, the present invention relates to a bonding agent for ceramics suitable for bonding objects made of ceramics and a method of bonding ceramics. The present invention relates to a bonding agent for ceramics that can firmly bond objects and a method for bonding ceramics. In recent years, with the development of industrial technology, high-temperature strength, heat resistance,
A variety of ceramics with excellent chemical resistance and electrical properties are attracting attention, and they are gaining attention as high-performance materials that can be applied to high-temperature structural materials, chemical industry materials, electronic industry materials, etc. It is progressing. However, it is extremely difficult to satisfy the various performances required for high-performance materials as described above with a single type of ceramic, and materials that can satisfy the various performances required for high-performance materials as described above are needed. Generally speaking, by bonding and combining dissimilar objects made of ceramics with different properties to each other or an object made of ceramics and an object made of metal, it is possible to achieve the requirements of high-performance materials such as those mentioned above. It is conceivable to use composite materials with mutually complementary performance. For example, the present inventors have previously researched electronic circuit substrates that have excellent characteristics as integrated circuit substrates or IC package materials, and by bonding silicon carbide thin plates and different types of ceramic thin plates, integrated circuit They realized that it is possible to exhibit extremely excellent characteristics as a material for a substrate or an IC package, and in Japanese Patent Application No. 16078/1987, it was proposed that a ceramic thin plate having a specific volume resistivity of 10 ⁶ Ωcm or more is A silicon carbide substrate for an electronic circuit, which is bonded to the surface of a silicon carbide thin plate by a bonding layer containing a metal as a main component, and a method for manufacturing the same. By the way, the silicon carbide sintered body thin plate and the different ceramic thin plate in the invention have at least one
The bonding layer is mainly composed of metals, but the bonding layer described above is particularly important when bonding objects with widely different coefficients of thermal expansion and applying them over a wide temperature range. Stress caused by the difference in thermal expansion can cause peeling or damage to objects, and it has been difficult to maintain strong bonding strength over a wide temperature range. Based on the above-mentioned viewpoints, the inventors of the present invention have conducted various studies to develop a bonding agent that can join objects with significantly different coefficients of thermal expansion. The alloy obtained by alloying metals with high
Furthermore, the inventors discovered that the method has a great effect of absorbing and relieving the stress caused by the difference in thermal expansion between the joined objects, leading to the completion of the present invention. The present invention relates to a bonding agent for ceramics and a method for bonding ceramics that can firmly bond objects made of the same or different types of ceramics to each other or objects made of ceramics and objects made of metal, that is, a bonding method for ceramics that has a particularly large coefficient of thermal expansion. The object of the present invention is to provide a ceramic bonding agent suitable for bonding different objects and a bonding method using the bonding agent. Next, the present invention will be explained in detail. In the present invention, it is necessary that the bonding agent for ceramics contains 50 to 99.7% by weight of Pb and Sn in total, and 1 to 98% by weight of Cu. The reason for this is that the alloy formed from the bonding agent with the composition described above has extremely excellent bonding properties for ceramic objects, and not only can an extremely strong bonding layer be formed with a relatively small amount, but also has high toughness. It is highly effective in absorbing and alleviating the stress caused by the difference in thermal expansion or contraction when objects with significantly different coefficients of thermal expansion are bonded together. This is because it is possible to prevent destruction due to thermal stress and to obtain a bonding layer that is dense and has excellent airtightness. Further, the reason why the composition range of the bonding agent is limited to the above range is that the Pb ₁ Sn
If the total content of
This is because it is difficult to maintain the weight below 50Kg/mm ² . In the present invention, the bonding agent is Pb, Sn, Cu
It is necessary to be mainly composed of a ternary system. The reason for this is that both Pb and Sn can easily form a uniform bonding layer by alloying with other metals contained in the bonding agent, and they also maintain the hardness of the bonding layer relatively soft. This is because Cu exhibits suitable plasticity, making it possible to form a bonding layer with extremely excellent bonding properties.On the other hand, when Cu is alloyed with other metals contained in the bonding agent, it improves hardness and plasticity. This is because the bonding agent has the effect of increasing the melting point of the bonding layer without significantly degrading the bonding agent, thereby widening the temperature range of application of the bonding agent. In addition to the above-mentioned effects, Sn also has the effect of significantly improving the bonding properties of the bonding layer because it easily diffuses into the alloy forming the bonding layer. In the present invention, Pb contained in the bonding agent,
The component ratios of Sn and Cu are as shown in Figure 1 of the attached drawing at point A (Pb: 97%, Sn: 2%, Cu: 1%).
%), point B (Pb: 35%, Sn: 55%, Cu: 10%),
Point C (Pb: 0%, Sn: 93.8%, Cu: 6.2%), Point D
(Pb: 0%, Sn: 2%, Cu: 98%), and the total amount of Pb, Sn and Cu must be at least 70% by weight of the total metal components. Therefore, a bonding layer with extremely excellent bonding properties can be formed. In the present invention, the bonding agent is preferably in the form of a powder or a preformed thin plate. When the binder is in powder form, the metal contained in the binder preferably has an average particle size of 200 μm or less. The reason is that when the bonding agent is in powder form, it is usually in the form of a paste or slurry, and this bonding agent is applied to at least one of the joining surfaces of the objects to be joined. Therefore, by setting the average particle size of the metal to 200 μm or less, it is possible to apply the metal extremely uniformly, and it is possible to easily form a uniform and dense bonding layer. On the other hand, when the bonding agent is in the form of a thin plate formed in advance, the bonding can be performed relatively easily by sandwiching the thin plate-like bonding agent between objects to be bonded and then heating them. In the present invention, the metal in the bonding agent is preferably alloyed in advance. The reason for this is that by alloying the metals to be bonded in advance, a uniform bonding layer can be easily formed in a relatively short time. In the present invention, when the binder is used in powder form, it is advantageous to mix a vehicle such as an organic binder with the binder to facilitate application. As the vehicle, at least one selected from, for example, butyl carbitol acetate, terpinol, polyethylene glycol, methyl cellulose, ethyl cellulose, polyvinyl alcohol, polyacrylic acid, polyacrylic ester, polymethacrylic acid, and polymethacrylic ester is used. That is advantageous. The melting point of the alloy formed from the bonding agent determines the usage conditions and bonding conditions of the bonded functional materials, so the higher the melting point, the better, based on the usage conditions.
Also, from the bonding conditions, it is advantageous to have the bonding temperature as low as possible, but in the present invention, if the functional material to be bonded with the bonding agent is mainly used as a substrate material, the chip is placed on the substrate and fixed. The working temperature of the Au-Si eutectic alloy method, which is generally used in the die bonding process and has excellent heat dissipation, heat resistance, and ohmic contactability, is around 400℃, and the hermetic sealing process of the substrate is also important. Since the working temperature of the low melting point glass method, which is widely used in electrical insulation and has excellent wettability with metals, glass, ceramics, etc., is 400 to 500°C, the melting point of the alloy formed from the bonding agent is 400°C. ℃ or more. If the melting point of the bonding agent is too high, the heating temperature during bonding will be high, and the effect of the difference in thermal expansion will be significant, causing damage or peeling of the bonded materials during cooling. It is preferable that the melting point of the bonding agent is 1200° C. or lower because it makes it easier to bond. In the present invention, the hardness (Hv) of the alloy formed from the bonding agent is preferably 50 Kg/mm ² or less. The reason for this is that if the hardness is harder than 50Kg/mm ^{2 ,} the bonding layer will have insufficient plasticity and will be less effective in absorbing and relaxing the stress caused by the difference in thermal expansion. is more suitable. In addition, it is advantageous for the hardness to be as soft as possible considering the effect of absorbing and relaxing the stress caused by the difference in thermal expansion, but if it is too soft, the bonding strength will be insufficient, so it should be at least 2 kg/mm ² . It's advantageous. Next, a method for bonding ceramics using the bonding agent of the present invention will be explained. According to the present invention, when joining objects made of the same or different types of ceramics to each other or an object made of ceramics and an object made of metal, Pb, Sn, After applying or placing a bonding agent made of Cu, the bonded surfaces are overlapped via the bonding agent, and then heated within a temperature range of 400 to 1300°C, thereby forming an alloy formed from the bonding agent. A bonding layer is formed and bonded. According to the present invention, the bonding agent is at least one selected from silicon carbide, beryllia, zirconia, mullite, sillimanite, cordierite, sialon, silicon nitride, boron nitride, alumina, titania, spinel, steatite, and forsterite. It is suitable for application to ceramics containing as a main component. According to the present invention, a silicon carbide sintered body is used as one of the objects to be joined, and a sintered body of alumina, mullite, sillimanite, etc. is used as the object to be joined to the silicon carbide sintered body. Good results can be obtained when Further, the bonding agent can be suitably applied to bonding an object made of ceramics and an object made of metal, but consideration should be given to the bonding strength and handleability between the object made of ceramics and the object made of metal. Then, it is advantageous to select a combination of the ceramic object and the metal object such that the difference in thermal expansion coefficient between them is 5×10 ^-6 /°C or less. According to the present invention, a metallized layer may be formed in advance on the bonding surface of the ceramic object to further improve the bondability with the bonding layer formed from the bonding agent. Methods for forming a metallized layer on an object made of ceramics include forming a metallized layer on the surface of an electronic circuit board using conventionally known methods such as heat-resistant metal powder sintering method, active metal method, thick film method, and thin film method. method can be applied. Further, according to the present invention, when applying the metallized layer as described above, a cermet layer with ceramic powder dispersed in the metallized layer is formed to improve the bondability with the bonding layer formed from the bonding agent. It can also be improved. According to the present invention, when a silicon carbide sintered body is used for any of the objects to be joined, the silicon carbide sintered body is heated in an oxidizing atmosphere in advance to oxidize the surface and form an oxide film layer. It is preferable that it is formed. The reason for this is that silicon carbide sintered bodies with an oxide film layer have a transition layer in which silicon carbide and oxide are intricately formed on the surface, and have excellent bonding properties for bonding layers or metallized layers. It is from. The mechanism by which the silicon carbide sintered body on which the oxide film layer is formed has excellent bonding properties with the bonding layer or the metallized layer is due to the presence of foreign substances such as free carbon and other impurities adhering to the surface of the silicon carbide sintered body. It is presumed that this is because the surface of the silicon carbide sintered body is oxidized and removed, or the surface of the silicon carbide sintered body is microscopically roughened and the actual bonding area is increased. be done. According to the present invention, when a uniform and dense oxide film layer is required on the surface of the silicon carbide sintered body, Al is applied to the surface of the silicon carbide sintered body in advance.
P, B, Ge, Ae, Sb, Bi, V, Zn, Cd, Pb,
Na, K, Li, Be, Ca, Mg, Ba, Sr or Zr
The silicon carbide sintered body is oxidized by applying a composition mainly composed of selected elements or their compounds, and then heating the composition in an oxidizing atmosphere to form a eutectic oxide layer. It is advantageous to prevent cristobalite formation of SiO ₂ produced by the process, and it is most preferable to apply Al or a compound thereof such as alumina sol. The heating temperature in the oxidizing atmosphere is 750~
Advantageously, the temperature is within the range of 1650°C. According to the present invention, the thickness of the bonding layer is from 0.01 to
Preferably, it is within the range of 3.0 mm. The reason for this is that if the thickness of the bonding layer is thinner than 0.01 mm, not only will it be impossible to obtain sufficient bonding strength between the objects to be bonded, but also there will be a difference in thermal shrinkage between the objects to be bonded during cooling after bonding. This is because it is difficult to absorb and relieve the stress caused by this, and it is easy to peel off.On the other hand, if it is thicker than 3.0 mm, the bonding strength will deteriorate. The most suitable result can be obtained when the thickness of the bonding layer is within the range of 0.1 to 1.0 mm. According to the present invention, the bonding layer needs to be formed within a temperature range of 400 to 1300°C. The reason for this is that it is desirable to form the bonding layer at a temperature as low as possible considering the stress caused by the difference in thermal contraction between the objects to be bonded during cooling after bonding. 400 since the travel point of the alloy is over 400°C.
This is because if the temperature is lower than 1300°C, it is difficult to form a bonding layer with excellent handling properties, which is the objective of the present invention.On the other hand, if the temperature is higher than 1300°C, there will be a difference in thermal shrinkage between the objects to be joined during cooling after joining. This is because the effect of the stress caused by this becomes significant, making it easy to peel off during cooling. According to the present invention, it is advantageous to use a non-oxidizing atmosphere as much as possible as the atmosphere when forming the bonding layer. When oxides having effects are mixed, or when the heating temperature is not so high that the effect of oxidation on the bonding layer is small, the bonding layer can be suitably formed in an atmosphere other than a non-oxidizing atmosphere, such as an air atmosphere. be able to. Next, the present invention will be explained with reference to examples. Example 1 88.8 parts by weight of lead powder with an average particle size of 20 μm, 5 parts by weight of copper powder with an average particle size of about 10 μm, and 88.8 parts by weight of lead powder with an average particle size of about 10 μm
4.8 parts by weight of tin powder having a diameter of 20 μm, 1.4 parts by weight of a silver powder having an average particle size of about 15 μm, and 100 parts by weight of ethyl alcohol were placed in a mortar, thoroughly mixed, and then dried to obtain a mixture. 15 parts by weight of ethyl cellulose and butyl carbitol acetate per 100 parts by weight of this mixture.
85 parts by weight were added and mixed in a mortar to obtain a bonding agent for ceramics. Next, the density is 3.16g/cm ³ and the shape is 30 x 30 x 2.
The bonding agent was applied to the surfaces of a silicon carbide sintered thin plate of 1.0 mm in diameter and an alumina sintered thin plate of 3.75 g/cm ³ in density and 30 x 30 x 1 mm in shape by screen printing. The coated surfaces were overlapped and fired to join the silicon carbide compact thin plate and the alumina sintered compact thin plate. The thickness of the obtained bonding layer is approximately 100μm, hardness (Hv)
was found to be approximately 12Kg/mm ² . Note that the silicon carbide sintered thin plate has a thickness of approximately 3 μm.
m, and an oxide film layer with an Al ₂ O ₃ /SiO ₂ molar ratio of 0.27, and a Mo-Mn layer of about 20 μm on the oxide film layer, while the alumina sintered thin plate has a thickness of about 20 μm. It has a 20 μm Mo-Mn metallization layer. Each of the metallized layers was formed by applying a Mo--Mn paste by screen printing and then firing it in a hydrogen gas stream. The bonding strength of the bonded body obtained as described above was determined by adhering a tensile strength measuring jig to the bonded body using an organic resin adhesive, as shown in Figure 2, and measuring the bonding strength by applying tensile stress. However, it was confirmed that the stress at which peeling occurred was 300 kg. Example 2 A bonding agent for ceramics having a composition as shown in Table 1 was prepared, and a bonded body was obtained in the same manner as in Example 1, except that the firing temperature was changed as appropriate. The hardness (Hv) of the resulting bonding layers was 20Kg/
It was found that it is softer than mm ² and has extremely excellent bonding properties. Further, the bonding strengths measured in the same manner as in Example 1 are shown in Table 1.

【table】

[Table] Example 3 The mixture of lead, copper, tin, and silver prepared in Example 1 was press-molded at a pressure of 3 t/cm ² to obtain a molded product with a thickness of 150 μm. The molded body was sandwiched between the silicon carbide sintered thin plate and the alumina sintered thin plate used in Example 1 and fired under the same conditions as in Example 1 to obtain a joined body. The thickness of the bonding layer was about 100 μm, and almost no defects such as pinholes were observed. Furthermore, the bonding strength measured in the same manner as in Example 1 was 290 kg. Example 4 A mixture having the same composition as that prepared in Example 1 was charged into a crucible and melted into an alloy at 900°C. The alloy was then cooled and solidified and then rolled to a thickness of about 100 μm. The rolled body was sandwiched between a silicon carbide sintered thin plate and an alumina sintered thin plate as in Example 3, and fired under the same conditions as in Example 1 to obtain a joined body. The bonding strength measured in the same manner as in Example 1 was 350.
It was Kg. Example 5 A ceramic bonding agent similar to that prepared in Example 1, but with the addition of 20 parts by weight of methylcellulose and 80 parts by weight of terpinol as a vehicle, a Si-Ni metallization layer with a thickness of approximately 20 μm. A silicon carbide sintered thin plate with a thickness of about 25 μm
A bonded body was obtained using an alumina sintered thin plate coated with a Mo-Mn metallization layer. The bonding strength measured in the same manner as in Example 1 was 300.
It was Kg. Example 6 Same as Example 1 but with 15 μm thick Wc
A bonded body was obtained using a silicon carbide sintered thin plate coated with a -Ni cermet layer and an alumina sintered thin plate coated with a 15 μm thick W metallized layer. The bonding strength measured in the same manner as in Example 1 was 320
It was Kg. Example 7 Same as Example 1, but with a thickness of 15 μm.
A bonded body was obtained using a silicon nitride sintered thin plate with a -Mn metallization layer and an alumina sintered thin plate with a 15 μm thick Mo-Mn metallized layer. The bonding strength measured in the same manner as in Example 1 was 280Kg.
It was hot. The thin plate of silicon nitride sintered body used was one in which an alumina sol aqueous solution was coated in advance and then oxidized to form an oxide film layer. Example 8 Same as Example 1, but sialon thin plate with a 20 μm thick Mo-Mn metallized layer after pre-oxidation treatment on the surface and forstellite with a 20 μm thick Mo-Mn metallized layer A bonded body was obtained using a thin plate. The bonding strength measured in the same manner as in Example 1 was 200
It was Kg. As described above, the present invention relates to a bonding agent that can firmly bond objects made of the same or different types of ceramics to each other or objects made of ceramics and objects made of metal, and a bonding method using this bonding agent. Therefore, it is possible to easily produce composite materials that can satisfy the various performances required in high-performance materials such as high-temperature structural materials, chemical industry materials, and electronic industry materials, and is suitable for industrial use. The contribution effect is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the preferred composition ranges of Pb, Sn, and Cu contained in the ceramic bonding agent of the present invention, and Fig. 2 is a jig for measuring the bonding strength of the bonded body carried out in the examples of the present invention. It is a figure showing an attachment form. DESCRIPTION OF SYMBOLS 1, 2...Object to be joined, 3...Joining layer, 4...Jig for measuring tensile strength, 5...Organic resin adhesive layer.

Claims (1)

[Claims] 1 Pb and Sn in a total content of 50 to
A bonding agent for ceramics comprising 99.7% by weight and 1 to 98% by weight of Cu. 2 The component ratio of Pb, Sn, and Cu contained in the bonding agent is, in terms of weight ratio, as shown in Figure 1 of the attached drawings, point A (Pb: 97%, Sn: 2%, Cu: 1%). , point B (Pb: 35%, Sn: 55%, Cu: 10%), point C
(Pb: 0%, Sn: 93.8%, Cu: 6.2%), point D
The bonding agent according to claim 1, which is within the range surrounded by (Pb: 0%, Sn: 2%, Cu: 98%). 3. Claim 1, wherein the metal contained in the bonding agent is a powder with an average particle size of 200 μm or less.
The bonding agent according to item 1 or 2. 4. The bonding agent according to claim 3, wherein the metal powder is a powder that has been alloyed in advance. 5. The bonding agent according to any one of claims 1 to 4, wherein the bonding agent is formed into a thin plate shape in advance. 6. The melting point of the bonding agent is within the range of 400 to 1200°C, and the hardness (Hv) of the bonding agent solidified after welding is 50 Kg/mm ² or less. The bonding agent according to any one of the above. 7 Their total content of Pb and Sn is 50~
A bonding agent for ceramics comprising 99.7% by weight of Cu, 1 to 98% by weight of Cu, and the balance containing Ag. 8 When joining objects made of the same or different types of ceramics to each other or to an object made of ceramics and an object made of metal, the joint surface of at least one of the objects to be joined contains a total of Pb and Sn. 50~ in quantity
After applying or placing a ceramic bonding agent containing 99.7% by weight and 1 to 98% by weight of Cu, the bonded surfaces are overlapped via the bonding agent, and then heated in a temperature range of 400 to 1300°C. A method for joining ceramics characterized by internal heating. 9 The ceramics include silicon carbide, beryllia,
The bond according to claim 8, which has at least one selected from zirconia, mullite, sillimanite, cordierite, sialon, silicon nitride, boron nitride, alumina, titania, spinel, steatite, and forsterite as a main component. Method. 10. The bonding method according to claim 8 or 9, wherein the bonding surface of the ceramic object is metallized in advance. 11. The joining method according to claim 8, wherein at least one of the ceramic objects is a silicon carbide sintered body. 12. The joining method according to claim 11, wherein the joining surface of the silicon carbide sintered body is heated in advance in an oxidizing atmosphere to oxidize the surface to form an oxide film layer, and then metallized. .