JPS63179915A - Epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To obtain the titled composition, capable of providing a cured article having excellent heat and impact resistance as well as adhesive property to lead frames or elements, by blending a novolak type epoxy resin with epoxy urethane resin and specific modified phenolic resin which is a curing agent in a specific proportion. CONSTITUTION:The aimed composition obtained by blending (A) 100pts.wt. novolak type epoxy resin with (B) 30-90pts.wt. modified phenolic resin prepared by reacting (i) 100pts.wt. novolak type phenolic resin with (ii) 2-50pts.wt. modified silicone oil having epoxy group and polyether group in one molecule and (C) 2-30pts.wt. epoxy urethane resin obtained by reacting (iii) an urethane prepolymer having NCO groups at the terminals with (iv) a compound having epoxy group and OH group. The component (B) can be obtained by reacting the components (i) with (ii) in the presence of a catalyst, e.g. triphenylphosphine, etc., at 120-180 deg.C for 1-4hr.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to an epoxy resin composition for semiconductor encapsulation, and more specifically, it relates to an epoxy resin composition for encapsulating semiconductors, and more specifically, it has excellent thermal shock resistance and adhesion to lead frames and elements. The present invention relates to an epoxy resin composition for semiconductor encapsulation which provides a cured product having the following properties.

(Prior Art) In recent years, in the field of encapsulation of semiconductor devices, with the increasing integration of semiconductor devices, various functional units on devices have become finer and device pellets themselves have become larger.

Due to these changes in element pellets, conventional sealing resins are no longer able to satisfy requirements such as thermal shock resistance. Epoxy resin compositions cured with phenol novolak resins, which have been conventionally used as sealing resins for semiconductor devices, have excellent moisture resistance, high-temperature electrical properties, moldability, etc., and have become the mainstream resin for molding.

However, when this type of resin composition is used to seal a large device pellet with a fine surface structure, phosphosilicate glass, which is a coating material to protect the aluminum (AQ) pattern on the surface of the device pellet, is sealed. PSG)'
This may cause cracks in the film or silicon nitride (SiN) film, or cracks in the element pellet.

In particular, when a thermal cycle test is carried out, this tendency is very large, resulting in defects in element characteristics due to pellet cracks and defects due to corrosion of the AQ pattern due to cracks in the protective film.

As a countermeasure, the stress on the internal sealing resin is reduced, and the PSG film or SiN film on the sealing resin and the element is
It is necessary to increase the adhesion with glass films such as membranes.

Furthermore, in order to prevent corrosion of the AQ pattern on the element surface as much as possible, the cured product must contain a low concentration of hydrolyzable halogen compounds, especially chlorine, and maintain a high level of electrical insulation performance during moisture absorption and high temperatures. There is a need.

(Problems to be Solved by the Invention) In view of the above points, in the field of low stress resins, terminal functional liquid rubber ( Japanese Patent Application Publication No. 5
7-42720), epoxidized butadiene copolymer (see JP-A-57-120), alkylphenol-modified phenol novolak epoxy resin (see JP-A-59-30820), siloxane-modified phenol novolac epoxy resin (Unexamined Japanese Patent Publication No. 58-2141
7 and 58-34825) and a powder of a linear organopolysiloxane block cured product (see JP-A-58-219218).

However, none of the above-mentioned resin compositions provides a cured product having sufficiently satisfactory thermal shock resistance and adhesion to lead frames and elements. In addition, deterioration in moldability such as mold staining was also observed.

As described above, an object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation that provides a cured product having excellent thermal shock resistance and adhesion to lead frames and elements, and also has good moldability.

[Structure of the invention]

(Means and effects for solving the problems) The present invention comprises: (1) 100 parts by weight of novolac type epoxy resin (
n) 2 to 5 parts of polyether-modified silicone oil having one or more epoxy groups and polyether groups in one molecule, per 100 parts by weight of novolac type phenolic resin.
30 to 90 parts by weight of a modified phenolic resin obtained by reacting 0 parts by weight in advance (III) A urethane prepolymer containing isocyanate groups at the terminals obtained from a polyhydroxyl compound and a polyisocyanate compound and having an epoxy group and a hydroxyl group An epoxy resin composition for semiconductor encapsulation characterized by comprising 2 to 30 parts by weight of an epoxy urethane resin obtained by reacting a compound.

Examples of the novolat type epoxy resin (I) which is one component in the composition according to the present invention include phenol novolac type epoxy resin, cresol novolac type epoxy resin, and halogenated phenol novolac type epoxy resin. These epoxy resins are one or two types.
It may be used in a mixed system of more than one species. Among the above epoxy resins, those having a softening point of 60 to 100°C are preferred,
Particularly preferred is one having a temperature of 70 to 85°C. Moreover, those having an epoxy equivalent of 100 to 300 are preferable, and those having an epoxy equivalent of 175 to 220 are particularly preferable.

In addition, epoxy resins other than those mentioned above, such as bisphenol A
General glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, halogenated epoxy resins, etc., such as type epoxy resins, should be used in combination with the above novolak type epoxy resins. Can be done. The blending amount is preferably 50% by weight or less based on the novolac type epoxy resin.

The modified phenolic resin (II) according to the present invention is obtained by reacting a novolak type phenolic resin and a polyether-modified silicone oil at high temperature using a catalyst. Each component will be explained below.

The novolac-type phenolic resin according to the present invention acts as a curing agent for epoxy resins, and includes, for example, those having two or more phenolic hydroxyl groups such as phenol novolak resin and cresol novolac resin. Among the novolac type phenolic resins, the softening point is 6.
Those having a temperature of 0 to 120°C are preferable, particularly preferably those having a temperature of 80 to 100°C, and a hydroxyl equivalent of 100
-150 is preferred, particularly preferably 10
It has a value of 0 to 110.

The polyether modified silicone oil according to the present invention has 1
Any silicone oil may be used as long as it has one or more epoxy groups and one or more polyether groups in its molecule. Silicone oils generally have the property of being difficult to dissolve in organic substances and water, but the above-mentioned polyether-modified silicone oils have improved this point and also have the feature of surface activity. Examples of the polyether used include polyethylene glycol, polypropylene glycol, ethylene glycol-propylene glycol copolymer, and polytetramethylene glycol. The polyether-modified silicone oil according to the present invention has these polyether groups and also has an epoxy group for reaction with a novolac type phenol resin.

A specific example is 5F-8421 (manufactured by Toshi Silicone Co., Ltd.).
can be given.

The blending amount of the polyether-modified silicone oil is 2 to 5% per 100 weight of novolac type phenolic resin.
It is preferable to react 0 parts by weight in advance. More preferably, it is 10 to 30 parts by weight. If it is less than 2 parts by weight, the effect of improving thermal shock resistance will not be sufficient, and if it exceeds 50 parts by weight, the mechanical strength of the cured product will decrease.

71 The modified phenolic resin (n) according to the present invention is obtained by reacting the above-mentioned novolac type phenolic resin and polyether-modified silicone oil at a temperature of 120 to 180°C for 1 to 4 hours. As a catalyst, imidazoles, amines such as diazabicycloundecene, and phosphorus compounds such as triphenylphosphine, which are usually used in the reaction between epoxy resin and phenol resin, can be used, but triphenylphosphine is particularly preferred because of its good electrical properties. . The amount of catalyst added is preferably 0.2 to 2% based on the total pre-reactant.
.

The blending ratio of the modified phenol resin is preferably in the range of 30 to 90 parts by weight based on 100 parts by weight of the novolak epoxy resin. If the blending ratio is less than 30 parts by weight, the strength of the cured product will be weakened, which is undesirable, while if it exceeds 90 parts by weight, the moisture resistance of the sealing resin will be lowered, which is undesirable.

Examples of the polyhydroxyl compound used as a raw material for the epoxy urethane resin (III) of the present invention include polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; caprolactone type, adipate type, 1,6
-Polyester polyols such as hexanediol carbonate type; polybutadiene or butadiene copolymers containing terminal hydroxyl groups; and polysiloxane compounds containing two or more hydroxyl groups in one molecule. These polyhydroxyl compounds preferably have a molecular weight of 1,000 to 5,000.

The polyisocyanate compound used in the present invention is a compound having two or more isocyanate groups in one molecule, and examples thereof include tolylene diisocyanate, diphenylmethane disisocyanate, hexamethylene diisocyanate, triphenylmethane triisocyanate, and the like.

The urethane prepolymer containing isocyanate groups at the terminals according to the present invention can be obtained by reacting the above-mentioned polyhydroxyl compound and polyisocyanate compound in the same manner as in the production method of ordinary isocyanate group-containing urethane prepolymers.

The compound having an epoxy group and a hydroxyl group used in the present invention is a compound having at least one epoxy group and one or more hydroxyl group in one molecule, preferably a compound having a molecular weight of 50 to 2000, for example,
Examples include glycidyl ethers of polyhydric alcohols such as glycidol, ethylene glycol monoglycidyl ether, and glycerin diglycidyl ether, and ordinary epoxy resins having hydroxyl groups.

According to the present invention, the urethane prepolymer described above is reacted with a compound having an epoxy group and a hydroxyl group at an equivalent ratio (hydroxyl group/isocyanate group) of 0.8 to 1.2 in a conventional manner. Epoxyurethane resin (III) can be obtained.

The blending ratio of the epoxy urethane resin (III) is usually 2 to 30 parts by weight, preferably 5 to 25 parts by weight, based on the novolac type epoxy resin. If this proportion is less than 2 parts by weight, the effects of improving thermal shock resistance and adhesion will not be sufficient, and if it exceeds 30 parts by weight, the mechanical strength and heat resistance of the cured product will decrease.

Next, a method for manufacturing the epoxy resin composition for semiconductor encapsulation of the present invention will be described.

The composition of the present invention can be prepared by melt-mixing the above-mentioned components using a heating roll, melt-kneading using a kneader, melt-mixing using an extruder, mixing with a special mixer after pulverization, or an appropriate combination of these methods. It can be easily manufactured.

The composition of the present invention may optionally contain a curing accelerator such as imidazole or a derivative thereof, a tertiary amine derivative, an organic phosphine derivative, a diazabicycloalkene derivative; zircon, silica, fused silica glass, alumina. , aluminum hydroxide, glass, quartz glass, calcium silicate, stone wax, calcium carbonate, magnesite,
Fillers such as clay, kaolin, talc, mica, asbestos, silicon carbide, boron nitride; Coloring agents such as carbon black; Mold release agents such as higher fatty acids and waxes; Epoxy silane, vinyl silane, amitucran, borane compounds, alkoxy Coupling agents such as titanate compounds and aluminum chelate compounds; known flame retardants containing antimony, phosphorus compounds, bromine and chlorine may also be blended.

(Example) Below, the present invention will be described in more detail with reference to Examples and Comparative Examples.

In addition, in Examples and Comparative Examples, all "r parts" indicate "parts by weight."

Planning 1 (Preparation of modified phenolic resin A) Novolak type phenolic resin (softening point 87°C, hydroxyl equivalent 104)
700i was melted at 150°C in a flask, and 100% polyether-modified silicone oil (SF
-8421) was added and mixed with stirring for 15 minutes, then 5 grams of triphenylphosphine was added as a catalyst, and the reaction was further carried out with heating and stirring for 1 hour to obtain modified phenol resin A.

Project U (Preparation of modified phenolic resin B) Polyether modified silicone oil of Synthesis Example 1 (SF-
Modified phenol resin B was obtained in the same manner as in Synthesis Example 1 except that the amount of 8421) added was changed to 2009.

ILLL (Synthesis of epoxy urethane resin a) Polytetramethylene glycol 2009 with hydroxyl value 56 and average molecular weight 2000 and tolylene diisocyanate 34.8
f was reacted with heating and stirring at 85° C. for about 5 hours under a nitrogen stream to obtain a polyurethane prepolymer containing terminal isocyanate groups.

Add 14.8 f of glycidol to this and heat under nitrogen stream for 6 hours.
The reaction was carried out at 0° C. for about 10 hours until the isocyanate groups disappeared to obtain epoxyurethane resin a. The resulting resin had an epoxy equivalent weight of 1,250.

1 Mochi A- (Synthesis of epoxy urethane resin) A polyurethane prepolymer containing terminal isocyanate groups obtained by reacting polycarbonate diol 100 fj with a hydroxyl value of 112 and an average molecular weight of 100 and hexamethylene diisocyanate 33.6 fj. Ethylene glycol monoglycidyl ether (23.6 fI) was added and reacted for about 9 hours at 70°C under a nitrogen stream to obtain an epoxy urethane resin. The resulting resin had an epoxy equivalent weight of 790.

Examples 1 to 5 Orthocresol novolac type epoxy resin (softening point 7
4℃, epoxy equivalent weight 200) (Epoxy resin A), brominated phenol novolac type epoxy resin (bromine content 30%, softening point 87℃, epoxy equivalent weight 288) (Epoxy resin B), novolac type phenol resin (softening point 8
7°C, hydroxyl equivalent 104), modified phenolic resins A and B, epoxy urethane resins a and b, polyether modified silicone oil (SF-8421, viscosity 3500)
cps, manufactured by Toshi Silicone Co., Ltd.), dimethyl silicone oil (TSF-451-10M), viscosity 100000
cps, Toshiba Silicone Co., Ltd. M), triphenylphosphine as a curing accelerator, carnauba wax as a mold release agent, carbon black as a coloring agent, half of fused silica as a filler, antimony dioxide and epoxy silane coupling as a flame retardant aid. The agents were blended in the composition ratio (parts by weight) shown in Table 1, kneaded with a twin-screw roll at 70 to 110°C, cooled and pulverized, and tableted to form 10 types of semiconductor encapsulation, including Comparative Examples 1 to 5. An epoxy resin composition was prepared.

Using the obtained composition, low pressure transfer molding 41
(Toa Seiki 50 ton press) at 175℃, 80kg
/d for 3 minutes, a large pellet evaluation sample element (8 mm x 8 nwn) having a PSG layer on the surface was sealed.

In order to evaluate thermal shock resistance 1 mechanical properties (flexural modulus, bending strength) and thermal properties (glass transition point, coefficient of thermal expansion) of the obtained sample element, various tests described below were conducted.

Thermal shock resistance test...The obtained sample element was heated to -65℃~1
The sample was subjected to cooling and heating cycles at a temperature of 50° C., and the number of cycles until PSG cracking was observed and measured. To check for PSG cracks, melt away the molding resin using fuming nitric acid.
Confirmed with a microscope.

The flexural modulus was measured according to JISK-6911.

Bending strength was measured according to JISK-6911.

The glass transition point was determined from the inflection point of the thermal expansion curve using a thermal dilatometer manufactured by Shinku Riko.

The thermal expansion coefficient was measured using a thermal dilatometer manufactured by Shinku Riko.

In addition, a red ink test was conducted to evaluate the adhesion to the lead frame.

Red Ink Test 1 ~ A sample was placed in a 2-atm pressure pressure cooker containing red ink, and the distance that the ink had penetrated into the reed after 8 hours was measured.

The results are shown in Table 2.

As is clear from the above results, the examples of the present invention have superior thermal shock resistance compared to the comparative examples, have no deterioration in moldability such as mold stains, and have little red ink penetration in the red ink test. , it can be seen that the adhesiveness with the lead frame is excellent.

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Oo C') Mede 11 recognition 3 111 pot ゝ-8 = Omibayashi 1 wing + g + 1 + 'iゝ-8 Tatsumi [Effect of the invention] As detailed above, the semiconductor of the present invention :'# The epoxy resin composition for sealing is one in which the cured product has excellent thermal shock resistance and adhesion to lead frames and elements,
It can be said that the practical value in applications such as highly integrated semiconductor devices is extremely large.

Agent Patent Attorney Noriyuki Chika Same Bamboo Flower Kikuo

Claims (2)

[Claims] (1) (I) 100 parts by weight of novolac type epoxy resin (II) 100 parts by weight of novolac type phenol resin, polyether-modified silicone oil having one or more epoxy group and polyether group in one molecule 2 ~50
Modified phenol resin obtained by reacting parts by weight in advance 30~
90 parts by weight (III) Epoxy urethane resin 2 to 30 obtained by reacting a urethane prepolymer containing an isocyanate group at the end obtained from a polyhydroxyl compound and a polyisocyanate compound with a compound having an epoxy group and a hydroxyl group. An epoxy resin composition for semiconductor encapsulation, comprising parts by weight. (2) The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein triphenylphosphine is used as a reaction catalyst between the novolac type phenol resin and the polyether-modified silicone oil.