JPH02166116A - Epoxy resin molding material for sealing electronic component - Google Patents

Abstract

PURPOSE:To obtain the title material improved in moldability and humidity resistance by mixing an epoxy resin with a phenolic compound, a specified reaction product, a solid silicone polymer and an inorganic filler. CONSTITUTION:An epoxy resin (A) having at least two epoxy groups in the molecule, desirably a novolac epoxy resin of an epoxy equivalent <=320, is mixed with a compound (B) having at least two phenolic hydroxyls in the molecule, desirably a novolac phenolic resin of a number-average MW of 300-600, a reaction product (C) obtained by reacting component A or B with a reactive silicone oil having 50 or lens functional groups per 100 epoxy or phenolic hydroxyl groups for 1-50hr in the presence of a catalyst in such amounts that the ratio of total epoxies to total phenolic hydroxyls in components A-C is 0.8-1.2. The obtained mixture is mixed with 2-10wt.% based on the total of components A-C, solid silicone polymer (D) of a max. particle diameter <=150mum and a hardness <=80 and 50-80vol.%, based on the total of the obtained molding material, inorganic filler.

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 moldability and moisture resistance.

[Conventional technology]

Conventionally, epoxy resin molding materials have been widely used for encapsulating electronic components such as coils, capacitors, transistors, and ICs. This is because the epoxy resin has well-balanced properties such as electrical properties, heat resistance, mechanical strength, and adhesion to the insert.

2. Description of the Related Art In recent years, in the field of electronic components, particularly ICs, there has been a trend to make packages lighter, thinner, shorter and smaller, while element sizes have become larger as parts become more sophisticated.

Therefore, in addition to high heat resistance, which is a conventionally required property, low stress properties are essential conditions for molding materials for sealing. Due to the requirement for high heat resistance, a resin system in which a novolac type epoxy resin, which is a polyfunctional epoxy resin, is cured with a phenol novolac resin, which is a polyhydric phenol, is generally employed. Furthermore, in order to reduce the stress, a method of adding and mixing various rubber components to lower the elastic modulus has been studied. As a result, epoxy resin molding materials in which silicone oil is added as a flexibilizer to the above-mentioned resin system with excellent heat resistance are now widely used. Since silicone oil is incompatible with the epoxy resin and curing agent that are the base resin of the molding material, fine particles are dispersed in the base resin (sea-island structure), making it possible to lower the elastic modulus while maintaining heat resistance.

However, with a molding material that is a simple blend of silicone as described above, the silicone and the base resin phase separate during molding, and the silicone tends to bleed, which tends to cause problems such as mold staining. As a solution to this problem, a method has already been proposed in which silicone and a base resin are pre-reacted, and good results have been obtained (for example, Japanese Patent Publication No. 36050/1983, Japanese Patent Publication No. 63/1983) 32807
Publication No.).

[Problem to be solved by the invention]

As mentioned above, if a method is adopted in which silicone is pre-reacted with the base resin and silicone is fixed to the base resin, moldability such as mold stains can be improved, but the problem is that moisture resistance is insufficient. The present invention provides an epoxy resin molding material for encapsulating electronic components that has improved moisture resistance without impairing moldability.

[Means to solve the problem]

As a result of extensive studies to solve the above problems, the present inventors discovered that the following molding materials are effective.
The present invention has now been completed.

That is, the present invention provides (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, (C) the above component (A), or An electronic component pair comprising (B) a reaction product of component and reactive silicone oil, (D) a solid silicone polymer having a maximum particle size of 150 μm or less and a hardness of 80 or less, and (E) an inorganic filler as essential components. The present invention provides epoxy resin molding materials for soil use.

The epoxy resin having two or more epoxy groups in one molecule of component (A) used in the present invention is not limited as long as it is a commonly used epoxy resin molding material for encapsulating electronic components. , phenol novolak type epoxy resin, epoxidized phenol and aldehyde novolac resins including Ortsukushi-sol novolac type epoxy resin, bisphenol A
1 Bisphenol B 1 Bisphenol F 1 Diglycidyl ether such as Bisphenol S, glycidyl ester type epoxy resin obtained by reacting polybasic acids such as phthalic acid and dimer acid with epichlorohydrin, polyamines such as diaminodiphenylmethane and incyanuric acid, and epichlorohydrin. There are glycidylamine type epoxy resins obtained by the reaction of A novolac type epoxy resin having an epoxy equivalent of 230 or less is preferred.

Compounds having two or more phenolic hydroxyl groups in one molecule of component (B) used in the present invention include phenols such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A and bisphenol F, and formaldehyde. There are novolac-type phenol resins obtained by condensation reaction under acidic catalysts, bisphenol A1 bisphenol F, polyvarabinyl phenol resins, and polyhydric phenols such as resorcinol, catechol, and hydroquinone, which can be used alone or in combination of two or more. Although it can be used, a novolac type phenolic resin is preferred from the viewpoint of cost and balance of properties. Further, the number average molecular weight is preferably 300 to 600. When the number average molecular weight is less than 300, heat resistance is insufficient,
This is because when it exceeds 600, the fluidity of the molding material decreases.

Next, the (C) component used in the present invention is a reaction product f of the above-mentioned (A) component or (B) component and a reactive silicone oil, and the functional groups of the reactive silicone oil are (A)
There is no particular restriction as long as it is a functional group that can react with the epoxy group in the component or the phenolic hydroxyl group in the component (B). Such silicone oil has a basic structure of dimethyl silicone, and has the terminal and/or side chain of this molecule,
It has a functional group such as an amino group, a carboxyl group, a mercapto group, a hydroxyphenyl group, an epoxy group, an alkoxy group, etc. In addition, one of the methyl groups is added to improve the compatibility with components (A) and CB). The method for synthesizing the 0 reactant may have a structure in which the moiety is substituted with a phenyl group, a polyoxyalkylene group, etc., depending on the selected functional group, in the presence of a conventionally known catalyst and in the presence of a solvent. This can be carried out by heating and stirring a mixture of component (A) or component (B) and reactive silicone oil in the presence or absence of the silicone oil. Suitable solvents include methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, etc. The reaction time varies depending on the functional group concentration, solubility, and reaction temperature of the reaction system, but is 1 to 5.
It is 0 hours.

What is important when synthesizing component (C) is to adjust the amount of functional groups in the reactive silicone oil so that some of the functional groups in component (A) or component (B), that is, epoxy groups or phenolic hydroxyl groups, remain. It is to be. That is, when the number of epoxy groups or phenolic hydroxyl groups is 100,
It is preferable to carry out the synthesis reaction by blending the silicone oil so that the number of functional groups is 50 or less. By using component (C) synthesized under such conditions, the molding material can be cured in the mold. When, (A) component, (B) component,
Component (C) is uniformly cured, and silicone as a flexible agent is uniformly dispersed and fixed in the cured resin. Also,(
For the reasons stated above, the (A) component and (B) component used in component C) synthesis have an epoxy equivalent of 2.
As the novolac type epoxy resin having a number average molecular weight of 30 or less and the component (B), a novolak type phenol resin having a number average molecular weight of 1300 to 600 is particularly preferable. The amount of component (C) added is (
A) + (B) + (C) It is preferably in the range of 5 to 70% by weight based on the total amount. This is because if it is less than 5% by weight, sufficient low stress properties cannot be obtained, and if it exceeds 70% by weight, the mechanical strength of the cured product will decrease.

The blending amount of the above components (A), (B), and (C) is 3
In order to obtain a well-balanced cured product, it is preferable to mix the components so that (total number of epoxy groups)/(total number of phenolic hydroxyl groups) is 0.8 to 1°2.

The solid silicone polymer as component (D) used in the present invention is:
The maximum particle size must be 150 μm or less and the hardness must be 80 or less. The hardness here refers to the Japan Rubber Association standard 5R.
Based on IS-0101, the values measured using the C-type hardness tester are shown. First, the reason why the maximum particle size is specified to be 150 μm or less is to prevent mold gate clogging from occurring during molding. The gate size of a mold for forming electronic components such as ICs has become smaller as packages become smaller and thinner, and is currently about 200 to 500 μm.

Therefore, in order to prevent molding troubles such as gate clogging, the maximum particle size must be 150 am or less. Next, regarding the hardness, if a material with a hardness exceeding 80 is used, the moisture resistance improvement effect will not be observed.
It is necessary to do the following. Specific examples of component (D) include:
Examples include high polymers of polyorganosiloxane such as polydimethylsiloxane, polymethylphenylsiloxane, and dimethylsiloxane-diphenylsiloxane copolymer. Furthermore, crosslinked products of these polyorganosiloxane polymers may be used, and functional groups such as silanol groups, hydroxy groups, carboxyl groups, vinyl groups, amino groups, mercapto groups, epoxy groups, methoxy groups, and ethoxy groups may be used in the structure. Base.

You may use the one which has. (D) The amount of component added is
(A) + (B) + (c) 2 to 1 for the total amount of ingredients
The content is preferably 0% by weight; if it is less than 2% by weight, there is no effect of improving moisture resistance, and if it exceeds 10% by weight, the effect of improving moisture resistance tends to be saturated, and mechanical strength may be lowered. The effect of improving moisture resistance (after humidification + VPS treatment) by adding components (C) and (D) was initially unexpected, but the reason is that silicone rubber (D) with a hardness of 80 or less It is thought that component (C) containing silicone exists at the interface of (2) and improves the bonding with the resin (A) and (B) components, making it stronger against the thermal shock caused by PS.

Next, the inorganic filler (E) component used in the present invention is an essential component for lowering the linear expansion coefficient of the cured product, and includes, for example, fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride,
Powders such as boron nitride, beryllia, magnesia, zirconia, forsterite, steatite, spinel, mullite, titania, potassium titanate, silicon carbide,
Examples include silicon nitride, single crystal fibers such as alumina, and glass fibers, but fused silica is preferable from the viewpoint of cost and balance of properties. Further, regarding the shape of the filler, either a square or a spherical shape can be used. A spherical filler is preferably used as part or all of the filler because it provides high fluidity. Moreover, it is preferable that the blending amount of component (E) is 50 to 80% by volume of the entire molding material.

The molding material of the present invention may contain a curing accelerator that accelerates the curing reaction between the epoxy resin and the compound having a phenolic hydroxyl group. Examples of the curing accelerator include 1,8-diaza-bicyclo(5,4,O)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol,
Tertiary amines such as tris(dimethylaminomethyl)phenol, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-
Imidazole such as heptadecylimidazole, organic phosphine such as tributylphosphine, methyldiphenylphosphine, methyldiphenylbosphine, triphenylphosphine, diphenylphosphine, phenylphosphine, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2 Examples include tetraphenylboron salts such as -ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholinetetraphenylborate.

The epoxy resin molding material for encapsulating electronic components of the present invention also includes flame retardants such as antimony trioxide, higher fatty acids, higher fatty acid metal salts, mold release agents such as ester waxes, colorants such as carbon black, and epoxy resins. Coupling agents such as silanes, aminosilanes, vinylsilanes, alkylsilanes, titanates, aluminum alcoholates, etc. can be used.

A general method for producing molding materials using the above raw materials is to thoroughly mix a raw material mixture of a predetermined amount using a mixer, etc., then knead it using a heated roll, extruder, etc., cool it, and crush it. By this, a molding material can be obtained.

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 indie-excidine molding, compression molding, and casting are also possible. .

〔Example〕

EXAMPLES The present invention will be explained below with reference to Examples, but the scope of the present invention is not limited to these Examples.

Example 1 Orthocresol novolak type epoxy resin (epoxy resin AI) with epoxy equivalent weight 200 and softening point 78°C 50
parts by weight, epoxy equivalent 400, softening point 70°C, brominated bisphenol A type epoxy resin (epoxy resin At) 20 parts by weight with bromine content 40%, hydroxyl equivalent 106,
A weight ratio of 48 parts by weight of a phenol novolak resin (curing agent B) having a softening point of 82° C. and a number average molecular weight of 450, dimethyl silicone oil having an aminopropyl group at both ends and an average degree of polymerization of 50, and the above epoxy resin A. 10/30 (
A compound obtained by reacting with a functional group ratio of 3.5/100) (
Reactant CI) 40 parts by weight, maximum particle size 105 μm 1 hardness 5
6 powdered silicone (solid silicone D, >5111
1.3 parts by weight of I-rephenylphosphine, 1.5 parts by weight of carnauba wax, 8 parts by weight of antimony dioxide, 1.5 parts by weight of carbon black, 3 parts by weight of α-glycidoxyprobyltrimethoxysilane, melted. Blending 400 parts by weight of silica powder and using a 10 inch diameter heating roll,
The mixture was kneaded at a kneading temperature of 80 to 90'' and a C1 kneading time of 10 minutes. The sheet-like kneaded material was cooled and then pulverized to prepare a molding material.

Example 2 Solid silicone D+5 parts by weight of Example 1 was mixed with a maximum particle size of 4
It was produced in the same manner as in Example 1, except that 5 parts by weight of powdered silicone (solid silicone D) having a diameter of 4 μm and a hardness of 43 was used.

Example 3 40 parts by weight of the reactant C of Example 1 was mixed with dimethyl silicone oil having glycidoxyprobyl groups at both ends and having an average degree of polymerization of 30, and the curing agent B+ described in Example 1. To 25 parts by weight of a compound (reactant C2) obtained by reacting phenylphosphine at a weight ratio of 10/15 (functional group ratio 5.8/100), 50 parts of epoxy resin A was added.
A molding material was produced in the same manner as in Example 1, except that the weight part was changed to 80 weight parts, and the curing agent B14B weight part was changed to 33 weight parts.

Example 4 A molding material was produced in the same manner as in Example 3, except that 5 parts by weight of solid silicone D in Example 3 was replaced with 5 parts by weight of solid silicone Di used in Example 2.

Comparative Example 1 Example 1 except that the solid silicone D+ of Example 1 was removed.
A molding material was prepared in the same manner.

Comparative Example 2 Example 3 except that solid silicone D of Example 3 was removed.
A molding material was prepared in the same manner.

The package was subjected to humidification treatment at 85° C./85% Rf (for 72 hours, followed by VPS treatment (215° C./90 seconds), and a PCT test was conducted to check for disconnection defects in the aluminum wiring at regular intervals.

In addition, in order to investigate the mold staining property of each molding material,
Discs of X3a*' were continuously molded (50 times), and the degree of dirt on the mold surface was visually observed.

The results of moisture resistance and mold stain resistance are shown in Table 1.

Margin below Next, using the molding material obtained above, a 54-bin QFP equipped with a test element with only 6 x 6 mm aluminum wiring was transfer molded, and post-cured at 180°C for 5 hours. According to the results shown in Table 1, 20 test packages were produced for each test package.From the results shown in Table 1, the tested products were excellent in both moisture resistance and mold stain resistance. On the other hand, Comparative Example 1.2 has good mold stain resistance but poor moisture resistance.

〔Effect of the invention〕

When electronic parts are encapsulated using the molding material of the present invention, the moldability of electronic parts without mold contamination is improved, workability is improved, and a highly reliable product with the same moisture resistance can be obtained.

Claims (3)

[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, (C) the above (A) component or (B) component; An epoxy resin for encapsulating electronic components, comprising as essential components a reaction product with a reactive silicone oil, (D) a solid silicone polymer having a maximum particle size of 150 μm or less and a hardness of 80 or less, and (E) an inorganic filler. Molding material. 2. 2. The epoxy resin molding material for encapsulating electronic parts according to claim 1, wherein component (A) is a novolac type epoxy resin having an epoxy equivalent of 230 or less. 3. The epoxy resin molding material for encapsulating electronic components according to claim 1, wherein component (B) is a novolac type phenolic resin having a number average molecular weight of 300 to 600.