JPH03215517A - Epoxy resin molding material for sealing electronic part - Google Patents

Abstract

PURPOSE:To prepare the title material excellent in the resistance to heat and thermal shock as well as in the moldability by compounding an epoxy resin with a specific solid particulate silicone polymer. CONSTITUTION:The title material is prepd. by compounding an epoxy resin having at least two phenolic hydroxyl groups in the molecule (A); a compd. having at least two phenolic hydroxyl groups in the molecule (B); a reaction product of compd. B with a siloxane compd. having a group reactive with compd. B (C); and a resin mixture obtd. by dispersing a mixture of an epoxidized organopolysiloxane with an aminated organopolysiloxane as fine particles in a dispersion comprising a part or the whole of compd. B and component C dispersed therein and then reacting the two organopolysiloxanes to harden (D). The obtd. material, when used in sealing an electronic part such as an IC or LSI, gives a molded product which is free from the degradation in appearance and excellent in the resistance to heat and thermal shock.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an epoxy resin molding material for encapsulating electronic components that has excellent thermal shock resistance, heat resistance, and moldability. (Prior Art) Conventionally, polycyclic epoxy resin molding materials have been widely used for encapsulating electronic components such as coils, capacitors, transistors, and ICs. The reason for this is that epoxy resin has well-balanced properties such as electrical properties, heat resistance, mechanical strength, and adhesion to inserts. As typified by ICs, there is a trend toward smaller and thinner packages, which causes the problem of packages cracking during thermal cycles. One way to improve the thermal shock resistance of epoxy resin molding materials is to modify the epoxy resin system with silicone polymers. Generally, silicone polymers are incompatible with epoxy resin systems, forming a structure in which fine particles break down in the epoxy resin, which has the effect of improving thermal shock resistance. However, since liquid silicone polymers are incompatible, although they improve the thermal shock resistance of the molding material, they ooze out during molding, causing problems such as leakage from mold clearances and deterioration of the appearance of molded products. It has the disadvantage of causing Furthermore, when a siloxane compound is modified with an epoxy resin or a curing agent in advance and used as a molding material in order to prevent seepage during molding, there is a problem in that the glass transition temperature generally decreases. (Problems to be Solved by the Invention) The present invention has been made to solve these drawbacks, and is an epoxy resin for encapsulating electronic components that has good thermal shock resistance, heat resistance, and excellent moldability. The aim is to provide resin molding materials. (Means for Solving the Problems) The present inventors have made extensive studies to solve the above problems, and have found that the above objectives can be achieved by blending a specific solid fine particle silicone polymer into an epoxy resin system. We have found the key to achieving this, and have completed the present invention. That is, the epoxy resin molding material for encapsulating electronic components of the present invention contains (Al) an epoxy resin having 2 to 12 epoxy groups in one molecule and (I31) having two or more phenolic hydroxyl groups in one molecule. In a molding material for encapsulating electronic components whose main resin component is (Bl), a part or all of (Bl) is used as a dispersion medium, and (Bl) is used as a dispersion medium,
) and a reaction product (C) with a siloxane compound having a reactive group that reacts with +131 is added as a disintegrating agent, and a mixture of an epoxy group-containing organopolysiloxane and an amino group-containing organopolysiloxane is dispersed in fine particles. Dispersed particles solidified by the reaction between organopolysiloxanes, including a dispersion medium and a dispersant, are blended as a DJ component. The epoxy resins having the above epoxy groups are not limited as long as they are commonly used in epoxy resin molding materials for encapsulating electronic parts, and include phenol novolac type epoxy resins and orthocresol novolac type epoxy resins. Epoxidized novolac resins of phenols and aldehydes, bisphenol A, bisphenol B, bisphenol F, bisphenol S
diglycidyl ethers such as, glycidyl ester type epoxy resins obtained by the reaction of polybasic acids such as phthalic acid dimer acid and shrimp chlorohydrin, glycidyl obtained by the reaction of polyamines such as diaminodiphenylmethane and isocyanuric acid and shrimp chlorohydrin. There are amine type epoxy resins, linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid, and aliphatic epoxy resins, and any number of these can be used in combination as appropriate. ．． The compounds used in the present invention (old components having two or more phenolic hydroxyl groups in one molecule include phenols such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, and bisphenol F) and formaldehyde. and polyhydric phenols such as novolac type phenol resins obtained by condensation reaction with and under acidic catalysts, bisphenol A, bisphenol F, borival vinyl phenol resins, resorcinol, catechol, and hydroquinone, which can be used alone or in combination of two or more. In addition, the equivalent ratio of +A+ to the epoxy resin (number of hydroxyl groups in (B)/number of epoxy groups in (A)) is:
Although not particularly limited, 0.7 to 1.3 is preferable. Next, the component (C) used in the present invention is a reaction product of the phenol compound of (Bl) and a siloxane compound having a reactive group that reacts with (1).The reactive group of this siloxane compound is a phenol compound and Anything that reacts may be used, such as epoxy groups, isocyanate groups,
There are vinyl groups, alkoxy groups, silanol groups, etc., and they may be present alone or in groups of 2lI or more, and the amount thereof may be one or more in the molecule of the siloxane compound. Furthermore, the skeleton of the siloxane compound is not particularly limited, and may include polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, or organopolysiloxane modified with a modifying group such as α-methylstyrene or polyether. may be used alone or in combination of two or more. Here, the blending ratio of the siloxane compound in component (C) is not particularly limited, and may be within a range that does not gel or separate during the production of component (TC). Also,
(A catalyst that promotes the reaction can be used in the production of the Cl component. The epoxy group-containing organopolysiloxane and amino group-containing organopolysiloxane used in the present invention are not particularly limited, but It is preferable that no phase droplets are observed visually with respect to the phenol compound used, and the reactivity is such that epoxy groups or amino groups are introduced into the molecular ends or within the molecules of homobolima and cobolima such as dimethylsiloxane, methylphenylsiloxane, and diphenylsiloxane. Generally commercially available liquid organopolysiloxanes can be used.The ratio of the epoxy group-containing organopolysiloxane to the amino group-containing organopolysiloxane is not particularly limited; The molar ratio of active hydrogen to amino groups is preferably in the range of 2:1 to 1:3.The reason for this is that when the ratio of epoxy groups becomes high, the appearance of the molded product deteriorates and the intended purpose cannot be achieved. However, if the ratio of amino groups increases, primary or secondary amino groups may remain in the molding material (YL), which may impair storage stability. The molecular weight of at least one of them is not particularly limited, but the weight average molecular weight of at least one of them is 1000.
It is preferable that the above is 5 from the viewpoint of thermal shock resistance. The mixture of organopolysiloxanes is prepared by using the above phenol compound as a dispersion medium (Cl component as a dispersing agent and dispersing the organopolysiloxanes into fine particles, and then heating as necessary to cause the organopolysiloxanes to react with each other and solidify in the form of fine particles. A phenol compound is suitable as a resin dispersion medium for dispersing the organopolysiloxane mixture.The reason for this is that the phenol compound promotes the reaction between the epoxy groups and amino groups of the organopolysiloxane. Therefore, the dispersed organopolysiloxane mixture can be easily solidified.Here, the ratio of the organopolysiloxane mixture to the phenol compound is in the range of 1:2 to 1:fO (body m). The reason for this is that when l:2 or more, it becomes difficult to disperse the organopolysiloxane into fine particles, and when l:10 or less, the amount of base resin used increases, which is disadvantageous in terms of production cost. The amount added is 0.001:1 based on the amount of organopolysiloxane mixture in the IDI component.
~1:1 (body vi). The reason for this is 0.
If it is less than 001:l (the dispersion stability effect of the Cl component is small and the particles will not form fine particles or the particles will agglomerate and will not be dispersed uniformly), if it is more than l:1 (the Cl component will cause oozing or marking on the surface of the molded product). There is no particular restriction on the method for dispersing the organopolysiloxane mixture, and methods such as a reaction pot equipped with a stirring device, a heating secondary, or a static mixer may be used. , a homogenizer, or other equipment that can perform sufficient dispersion operations is used.If the phenol compound to be used is solid at room temperature, it is necessary to heat it to melt it, but if it is liquid, it may be carried out at room temperature.
After the organopolysiloxane mixture is dispersed in fine particles in the phenol compound in this manner, the mixture is reacted at room temperature to 150° C. for 30 minutes to 10 hours, thereby solidifying the organopolysiloxane mixture while remaining dispersed in the fine particles. This reaction step can be carried out in an apparatus for dispersing the organopolysiloxane mixture, but it may also be carried out separately by taking out component (D) after dispersion and using a constant temperature bath or the like. The organopolysiloxane mixture is dispersed in fine particles in a part or all of the Dl component used in the present invention, i.e., a phenol compound (Bl) with a specific dispersant (C) added, and then dispersed by reaction between the organopolysiloxanes. In the resin mixture obtained by solidifying the particles, it is necessary that the dispersed particle size of the organopolysiloxane reactant is 100 μm or less for 90% by weight or more, and the average particle size is 50 lLm or less. Being an IIT
Delicious. This restriction on particle size is related to moldability when molding the intended electronic component. -・Generally IC,
The gate size of the mold for molding electronic components such as transistors is around 0.5+in+ at the narrow part, and in order to prevent gate clogging during molding, a particle size distribution of 100 μm or less is required to be 90ffi% or more. In addition, to counter the phenomenon that the gold wire connecting the element and the lead is deformed during molding, it is preferable that the particle size of the dispersed component is 10 0 tt m or less. The diameter is preferably 50 gm or less. The hardness of the fine particles of the organopolysiloxane reactant can be set arbitrarily by the functional group equivalents of the two types of organopolysiloxanes used and the equivalent ratio of epoxy groups to amino groups, but it is possible to set the hardness of the fine particles of the organopolysiloxane reactant to improve the softness and package crack resistance. It has a cheating effect. By uniformly dispersing such soft solid particles in the molding material 4, thermal shock resistance, typified by package crack resistance, is significantly improved, and there is no drop in glass transition temperature (Tg). Excellent properties can be obtained. In addition, since organopolysiloxane is added in the form of solid fine particles, it is likely to cause problems with epoxy molding materials modified with siloxane compounds.
It has the advantage of not staining molded products or molds due to siloxane compounds exuding during molding. If seepage occurs in the molded product, it will cause problems such as poor appearance and poor marking performance, and if the mold becomes dirty, the mold must be cleaned more frequently. In particular, cleaning molds requires a great deal of effort and time, so using molding materials that do not generate dirt is a major advantage in terms of productivity. Furthermore, the epoxy resin molding material for encapsulating electronic components of the present invention may contain a curing accelerator that accelerates the curing reaction between the epoxy flN resin and the compound having a phenolic hydroxyl group. Examples of the curing accelerator include ■,8-diazabisic(5,4.0)undecene-7, triethylenediamine, benzyldimethylamine, t-liethanolamine, dimethylaminoethanol, tris(dimethylaminomethyl ) Tertiary amines such as phenol,
2-methylimidazole, 2-phenylimidazole,
Imidazoles such as 2-phenyl-4-methylimidazole and 2-heptadecyl imidazole, organic bosphines such as tribudylphosphine, medyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine, tetraphenylphosponium tetraphenyl Examples include tetraphenylboron salts such as borate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazoletetraphenylborate, and N-methylmorpholinetetraphenylborate. The epoxy resin molding material for encapsulating electronic components of the present invention also includes fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate,
Powders of silicon carbide, boron nitride, beryllia, magnesia, dinoreconia, phenolesteride, steatite, subinel, mullite, titania, potassium titanate,
Silicon carbide, silicon nitride, single crystal fibers such as alumina, glass fibers, etc. can be blended in IIIE or higher. The amount of the inorganic filler blended is not particularly limited, but is preferably 40 to 80% by volume. In addition, the epoxy resin molding material for encapsulating electronic components of the present invention includes higher fatty acids, higher fatty acid metal salts, mold release agents such as ester waxes, colorants such as carbon black, epoxy silanes, aminosilanes, alkylsilanes, and vinylsilanes. , organic titanates, aluminum alcoholates, and the like can be used.

This is a general method for producing molding materials using raw materials such as those shown in L. After thoroughly mixing a raw material mixture with a predetermined amount using a mixer, etc., kneading with a hot roll, extruder, etc., and cooling. , By crushing, the molding material can be made into {1. The most common method for sealing electronic components using the molding material obtained in the present invention is low-pressure transfer molding, but methods such as injection molding, compression molding, and casting are also possible.
The molding material according to the present invention has excellent moldability, and while maintaining a high rg, it is superior to flexible bamboo, and the molding material has great advantages in terms of gastric construction. That is, IOO
A feature of this method is that soft, rubber-like solid particles of less than gm can be added to molding materials at low cost. Generally 100Izm
It is difficult to produce the following rubbery substances by crushing bulk materials, and the cost is also high. There are also methods to obtain organopolysiloxane particles by emulsion polymerization, suspension polymerization, etc., but this requires the removal of the surfactant at the same time as the dispersion medium. Compared to the latter method, the production method of the present invention uses the base resin used in the molding material as the dispersion medium and dispersant, so the organopolysiloxane is dispersed and cured together with the dispersion medium and dispersant. It is possible to mix them together, which is very advantageous from a cost standpoint. Furthermore, since the organopolysiloxane particles can be handled as dispersed in a dispersion medium rather than being collected individually, there is no need to worry about soft particles agglomerating together. From the above points, the present invention exhibits excellent features from a manufacturing standpoint as well. (Function) The reason why an epoxy resin molding material with excellent thermal shock resistance and moldability can be obtained by the present invention is that (
Using part or all of Ill as a dispersion medium and a reaction product (TC) of (f3) and a siloxane compound as a dispersant, an organopolysiloxane mixture that is incompatible with the dispersion medium is dispersed into fine particles, and then the organopolysiloxane is self-dispersed. This is due to the use of DJ as a flexibilizer.In other words, the organopolysiloxane reactant in the Dl component contains solid particles with a particle size of 100 μm or less. It is a rubber-like substance (due to the dispersion stabilizing effect of the Cl component, its particle size becomes extremely small and uniform, and as it is uniformly dispersed in the molding material, excellent thermal shock resistance is obtained. Since the organopolysiloxanes are not compatible and form a phase-separated structure, the original glass transition temperature of the base resin is not lowered, and therefore the heat resistance is also good. Because it separates into the molding material as a solid, there is no need to worry about it seeping out during molding, and it will not stain the molded product or mold.The above effects provide a composition with excellent thermal shock resistance, heat resistance, and moldability. (Example) The present invention will be explained below with reference to Examples, but the scope of the present invention is not limited to these Examples.Production of component (C) Phenol with a softening point of 83°C 300 ml of 40 g of epoxy polyether modified silicone oil SF8421 (trade name manufactured by Torre Silicone Co., Ltd.) with an epoxy equivalent of 9.000 was melted into 120 g of novolak resin.
The mixture was added while stirring in a flask, 2 g of triphenylphosphine was added as a catalyst, and the resultant mixture was reacted at 150°C for 3 hours, which was used as a dispersant [1]. Dispersant [I] was a transparent pale yellow solid resin. In addition, phenol novolac resin 1 2 with a softening point of 83°C
40 g of methoxy group-containing silicone oil KR2 1 3 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) with a methoxy equivalent of 157 was added to the melted 0.0 g of p-}luenesulfonic acid while stirring in a 30 Owl flask. was added as a catalyst and reacted at 150°C for 3 hours, and the resulting product was used as a dispersant [11]. The dispersing agent [11] was a transparent pale yellow solid resin. (Viscosity 60cs (25℃) shown in the manufacturing structural formula of DJ component, epoxy p
1.8 0 017) Shin'): I-shin oil X-22
-163B (same as above) 45g and viscosity 3.500cs (25°C) shown by the structural formula. A mixture of 25 g of silicone oil KF861 (same as above) with an amine equivalent of 2.0 0 0 and 210 g of a phenol novolak resin with a hydroxyl group of 1 0 6 and a softening point of 83° C. and a dispersant [IJ 21 g] melted at a temperature of 150°C. was added to the solution while stirring and allowed to react for 1 hour, and the resulting material was used as the flexibilizer [I]. The organopolysiloxane reaction product obtained by dissolving the flexibilizer [11] in acetone and removing the phenolic resin was obtained as a nearly spherical solid powder, with an average particle size of about 10 μm and no particles larger than 100 szm. There wasn't. Also, silicone oil KFIOI (same as above) with a viscosity of 2.000 cs (150°C) and an epoxy equivalent of 350 as shown by the structural formula
2 g and the viscosity shown by the structural formula: 3.5 0 0 c's (25°C) 13.800 (7) amine/I7 = 1-N/l, X-2
2-3801C (same) 2》58g was mixed, ・Dispersant [
A flexible agent [
11]. Flexible agent [II] When silicone fine particles were extracted in the same manner as flexible agent [I], almost spherical solid fine particles were obtained, and the average particle size was 15 μm and 100 μm.
There were no particles larger than m. Production of epoxy resin molding material Cresol novolak type epoxy resin with epoxy equivalent of 220 and softening point of 78°C, epoxy equivalent of 375 and softening point of 80
℃, brominated bisphenol A type epoxy resin with bromine content of 48% by weight, phenol novolac resin with hydroxyl group of 1106, softening point of 83℃, 1.8-diazabisic acid (5.
4.0) Undecene-7, carnauba wax, andimony trioxide, carbon black, γ as a coupling agent
- Glycidoxib-trimethoxysilane, quartz glass powder, and flexibilizers [I] to [111] were blended in the weight ratio shown in Table 1, and the cross-wire temperature was 80 to 90°C, and the cross-wire was rolled under the conditions of 110 minutes. Molding materials of Examples 1 and 2 and Comparative Examples 1 to 3 were prepared by Ii ray. Table 2 shows the properties of the molding materials obtained in the Examples and Comparative Examples, and Table 3 shows the details of the property evaluation method. As a result, the thermal shock resistance of the molding materials obtained in Examples 1 and 2 was significantly improved compared to the molding material without the addition of a flexibilizer obtained in Comparative Example 2, and the appearance of the molded products was also good. The glass transition depth, which is an index of heat resistance, did not decrease and was good. In particular, Example 1 was superior in thermal shock resistance to the molding material obtained in Comparative Example 3, in which no dispersant was added when producing the flexible agent [11], and the effect of adding a dispersant was was there. The molding material of Comparative Example 1 using silicone oil as a flexibilizer has good thermal shock resistance, but the appearance of the molded product becomes cloudy, which poses a practical problem. The following margin table
7 Table 2 (Effects of the present invention) IC. If electronic components such as LSIs are sealed, as shown in the examples, there will be no moldability problems such as deterioration in the appearance of the molded product that can occur when incompatible flexibilizers are used, and the heat resistance will be improved. , it is possible to obtain a product with excellent thermal shock resistance, and its industrial value is great.

Claims (1)

[Claims] 1. (A) an epoxy resin having two or more epoxy groups in one molecule, (B) a compound having two or more phenolic hydroxyl groups in one molecule, and (C) the above (B) ), a reaction product with a siloxane compound having a reactive group that reacts with (B), and (D) a part or all of the above (B) as a dispersion medium, and the above (
A resin mixture obtained by dispersing fine particles of a mixture of an epoxy group-containing organopolysiloxane and an amino group-containing organopolysiloxane and curing the organopolysiloxanes by reaction with each other is used as an essential component. An epoxy resin molding material for encapsulating electronic components. 2. Claim 1, wherein 90% or more of the organopolysiloxane reactant in component (D) has a particle diameter of 100 μm or less.
An epoxy resin molding material for encapsulating electronic components as described in . 3. The quantitative ratio of the siloxane compound in component (C) to the organopolysiloxane mixture in component (D) is 0.001:1 to 1:1 (by volume), and the phenol compound in component (D) The epoxy resin molding material for encapsulating electronic components according to claim 1, wherein the organopolysiloxane mixture has a quantitative ratio of 2:1 to 10:1 (by volume).