JPH02855B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an epoxy resin composition for semiconductor encapsulation, particularly to an epoxy resin composition for semiconductor encapsulation that has excellent adhesiveness to ceramic substrates. Conventionally, epoxy resin compositions have been used to resin-seal semiconductor elements mounted on the ceramic stem surface, but the molded bodies obtained by resin-sealing can be used in different temperature environments and in different atmospheres. If the ceramic surface and the cured resin body are placed on the surface, cracks will occur at the interface between the ceramic surface and the cured resin body, and in more severe cases, a peeling phenomenon will occur. Possible ways to overcome these drawbacks include adding a large amount of filler or lowering the glass transition temperature of the cured resin, but if the semiconductor element is a light emitting diode, the former will reduce the light transmittance. This is not desirable as it may worsen the condition. Moreover, in the latter case, heat resistance deteriorates and the product tends to become cloudy even in a boiling test. In addition, in the case of light emitting diode molds, 1 to 20% by weight of ultrafine silica powder is added to a resin composition with high light transmittance to create a light diffusion effect. The adhesion between the silica powder and the silica powder was poor, and a cloudy phenomenon was observed in the boiling test. In addition, as a conventional method for improving resin compositions for semiconductor devices to prevent semiconductor devices other than light-emitting diodes, it is possible to add a large amount of filler to achieve low-line distension. There is also a limit to the amount of additive that can be added depending on the required properties.Furthermore, in the case of improving heat cycle characteristics, it is often not possible to meet the requirements by simply improving low linear expansion. The present invention is made to improve such drawbacks, and is characterized by adding 0.2 to 5 parts by weight of γ-mercaptopropyltrimethoxysilane to 100 parts by weight of an epoxy resin system containing an epoxy resin and a curing agent. , relates to an epoxy resin composition for semiconductor encapsulation for encapsulating a semiconductor element placed on a ceramic stem surface. The epoxy resin composition used in the present invention is generally liquid at room temperature for the above-mentioned ceramic stem potting, but it may have any other properties. Examples of the epoxy resin include known bisphenol epoxy resins, phenol novolak epoxy resins, and cyclo epoxy resins. For optical semiconductor device sealing applications, it is best to use acid anhydride curing agents from the viewpoint of transparency and heat discoloration resistance. Examples of these curing agents include tetrahydrophthalic anhydride, hexanhydride, Examples include hydrophthal, phthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and hemicic anhydride. Examples of the curing accelerator used in combination with the acid anhydride curing agent include imidazoles such as 2-methylimidazole and 1-benzyl-2-methylimidazole, tertiary amines such as benzyldimethylamine, tin octylate, Examples include carboxylic acid metal salts such as lead octylate. In addition to the above-mentioned acid anhydride-based curing agents, curing agents used for purposes other than encapsulating optical semiconductor devices include diaminodiphenylsulfone, 4,4'-methylene dianiline, m-phenylene diamine, and o-phenylene. Amine-based curing agents such as diamines can be mentioned. In the present invention, it is possible to incorporate known additives into the epoxy resin system if necessary. Examples of these include inorganic fillers such as silica, alumina, talc, clay, and glass fiber;
Examples include flame retardants such as antimony oxide halides and phosphides, mold release agents, and pigments. In order to actually seal a semiconductor element using the composition of the present invention, it may be carried out by a conventional method such as potting or transfer molding. In the present invention, the amount of γ-mercaptopropyltrimethoxysilane to be added to the epoxy resin system is 100%.
The reason for limiting it to 0.2 to 5 parts by weight is
Addition of 0.2 parts by weight or less has no effect;
This is because the heat resistance properties of the cured product obtained above are reduced. A semiconductor element sealed body obtained by sealing a semiconductor element placed on a ceramic stem surface with the epoxy resin composition of the present invention as described above has the following effects. (a) No cracks or peeling will occur at the interface between the ceramic stem surface and the cured resin body even if the semiconductor element encapsulation is placed in different temperature environments (b) Because of (a) above, when the resin composition of the present invention is used to seal a semiconductor element mounted on a ceramic stem surface, it is possible to seal the semiconductor element mounted on the ceramic stem surface without adding a large amount of filler to the sealing resin as in the conventional case. It is possible to obtain a semiconductor element sealed body that is excellent in thermal cycle tests. (C) When adding ultrafine silica powder to the molding resin of a semiconductor element molding to create a light diffusion effect, conventional moldings have poor boiling test properties and the cured resin becomes cloudy; The sealed body obtained from the composition of the present invention does not have such drawbacks. The present invention will be specifically explained below using examples. Parts in the examples are parts by weight. Example 1 Epoxy resin (Epicote 828 manufactured by Siel Corporation), curing agent (methylhexahydrophthalic anhydride), tin octylate, and silane coupling agent (γ-mercaptopropyltrimethoxysilane) were blended in the amounts shown in Table 1 below. A characteristic test (cold/hot cycle test) was performed on a sample obtained by potting the liquid resin on a ceramic stem and heating and curing it in a dryer at 120°C for 16 hours. The results are also listed in Table 1 below. Note that Table 1 also shows the case where no silane coupling agent was added.

【table】

[Table] In the thermal cycle test results in Table 1 above, the denominator indicates the total number of samples used, and the numerator indicates the number of samples in which cracks were found at the boundary between the cured resin and the ceramic stem surface as a result of the thermal cycle test. Example 2 A resin composition was prepared in the same manner as in Example 1 using the formulations shown in Table 2 below, and a thermal cycle test was conducted in the same manner. The results are listed in Table 2.

[Table] Example 3 A resin composition was prepared in the same manner as in Example 1 using the formulations shown in Table 3 below, and a thermal cycle test was conducted in the same manner. The results are listed in Table 3.

[Table] Example 4 In the formulation of No. 1 to No. 5 of Example 1, each particle size was 1 to 1.
After adding 7g of 10μ fine silica powder and mixing uniformly, it was cured under the same conditions as in Example 1, and the resulting cured product was
When boiled for 48 hours, the cured product of composition No. 1 developed cloudiness, but the cured products of No. 2 to No. 5 did not develop cloudiness. Example 5 A resin composition was prepared in the same manner as in Example 1 using the formulations shown in Table 4 below, and samples were prepared in the same manner as in Example 1. Table 4 shows the results of a pressure cycle test performed on the obtained sample.

[Table] In the characteristic values in Table 4, the denominator indicates the number of samples, and the numerator indicates the number of samples that failed as a result of the characteristic test. Judgment as good or bad was made if peeling occurred at the boundary between the ceramic stem and the cured resin as a result of the characteristic test.

Claims (1)

[Claims] 1. A method for sealing a semiconductor element placed on a ceramic stem surface, characterized by adding 0.2 to 5 parts by weight of γ-mercaptopropyltrimethoxysilane to 100 parts by weight of an epoxy resin system containing an epoxy resin and a curing agent. An epoxy resin composition for semiconductor encapsulation.