JP3143721B2 - Epoxy resin composition for sealing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for encapsulation, particularly a semiconductor encapsulation epoxy resin, which provides a cured product having high heat resistance, excellent hygroscopicity and low stress, and excellent reactivity. It relates to a resin composition.

[0002]

2. Description of the Related Art In recent years, with the increasing integration of semiconductor devices,
Various characteristics required for a sealing material of a semiconductor element have become severe, and in particular, reduction of internal stress, high glass transition temperature, and crack resistance during solder immersion have become important issues. However, epoxy resins generally used at present have not been able to sufficiently satisfy their required properties.

[0003] That is, as the integration of semiconductor devices has advanced,
2. Description of the Related Art As semiconductor devices have become significantly larger, packages themselves have become smaller and thinner. In addition, the mounting of semiconductor devices has also shifted to surface mounting.

In surface mounting, a semiconductor device is directly immersed in a solder bath and is exposed to a high temperature, so that a high glass transition temperature is required. If the internal stress is high, a shift in aluminum wiring and a crack in passivation are caused. become. In addition, when the package is exposed to the high temperature, a large stress is applied to the entire package due to the expansion of the absorbed moisture, and the sealing material is cracked.

[0005] For this reason, a sealing material having good solder crack resistance is required to have high heat resistance, excellent low moisture absorption and excellent low stress, and a cresol novolak type epoxy resin which is mainly used at present is used. An epoxy resin sealing material comprising a phenol novolak resin curing agent has become insufficient in heat resistance, low moisture absorption and low stress.

In general, it is known that tetramethyl biphenol type epoxy resin is excellent in solder crack resistance due to low stress and low moisture absorption (Japanese Patent Application Laid-Open No. 61-47725). ), The glass transition temperature is not sufficient, and the reactivity is inferior. When a biphenol-type epoxy resin having no methyl substituent is used, the glass transition temperature is increased and the reactivity is improved (see JP-A-2-18742).
No. 0), the low hygroscopicity is impaired, and the biphenol type epoxy resin itself has a very high melting point and poor solubility, which makes it difficult to produce an epoxy resin and to prepare a resin composition using the same. There were drawbacks.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides an epoxy resin composition for encapsulation which has high heat resistance, can provide a cured product excellent in low moisture absorption and low stress, and has excellent reactivity. It is something to offer.

[0008]

Means for Solving the Problems The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, have achieved the object by using an epoxy resin having a biphenol skeleton having a specific substituent. Is what I was able to do.

That is, the epoxy resin composition of the present invention comprises:

[0010]

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(Wherein R ¹ and R ² each have 1 carbon atom)
10 to 10 alkyl groups or phenyl groups, and n is a number of 0 to 5 on average. A) a disubstituted biphenol type epoxy resin represented by

(B) A composition comprising a polyhydric phenol resin as an essential component.

The (a) di-substituted biphenol type epoxy resin represented by the above general formula used in the epoxy resin composition of the present invention comprises the above-mentioned di-substituted biphenols having R ¹ and R ² substituents and epihalohydrin Is subjected to a condensation reaction in the presence of an alkali to give an epoxy resin.

The disubstituted biphenols used as raw materials for producing the disubstituted biphenol type epoxy resin include, for example, 3,3'-dimethyl-4,4'-biphenol,
3′-diethyl-4,4′-biphenol, 3,3′-
Examples thereof include dibutyl-4,4'-biphenol, 3,3'-diphenyl-4,4'-biphenol, and 3-methyl-3'-butyl-4,4'-biphenol.

If one or a mixture of two or more of these disubstituted biphenols is reacted with epihalohydrin, the epoxy resin used in the present invention can be obtained. Representative examples of the reaction are described in detail below.

First, a di-substituted biphenol is dissolved in an amount of epihalohydrin corresponding to 2 to 20 mol per mol of the phenolic hydroxyl group to form a uniform solution. Then, while stirring the solution, 1-2 moles of an alkali metal hydroxide per 1 mole of a phenolic hydroxyl group is added as a solid or an aqueous solution and reacted. This reaction can be performed under normal pressure or reduced pressure, the reaction temperature is usually
The temperature is about 40 to 105 ° C for the reaction under normal pressure, and about 40 to 80 ° C for the reaction under reduced pressure. In the reaction, the reaction solution is azeotroped while maintaining a predetermined temperature as needed, and the condensate obtained by cooling the volatile vapor is separated into oil / water,
The oil is removed from the reaction system by removing the oil from the reaction system. The alkali metal hydroxide is added intermittently or continuously over a period of 1 to 8 hours in order to suppress a rapid reaction. The total reaction time is usually about 1 to 10 hours.

After completion of the reaction, insoluble by-product salts are removed by filtration or removed by washing with water, and unreacted epihalohydrin is removed by distillation under reduced pressure to obtain the desired epoxy compound.

In this reaction, epichlorohydrin or epibromohydrin is usually used as epihalohydrin, and NaOH or KOH is usually used as alkali metal hydroxide.

In this reaction, quaternary ammonium salts such as tetramethylammonium chloride and tetraethylammonium bromide; tertiary amines such as benzyldimethylamine and 2,4,6-tris (dimethylaminomethyl) phenol; Catalysts such as imidazoles such as 2-ethyl-4-methylimidazole and 2-phenylimidazole; phosphonium salts such as ethyltriphenylphosphonium iodide; and phosphines such as triphenylphosphine may be used.

Further, in this reaction, alcohols such as ethanol and isopropanol; acetone,
Inert organic solvents such as ketones such as methyl ethyl ketone; ethers such as dioxane and ethylene glycol dimethyl ether; aprotic polar solvents such as dimethyl sulfoxide and dimethylformamide may be used.

The epoxy resin composition for encapsulating a semiconductor according to the present invention is a composition comprising (a) the di-substituted biphenol type epoxy resin as an epoxy resin. Resins can be used in combination. Other epoxy resins that can be used in combination include, for example, bisphenol A, bisphenol F, resorcin, hydroquinone, biphenol, tetramethylbiphenol, dihydroxynaphthalene, phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, dicyclopentadiene Various phenols such as phenolic resin, terpene phenolic resin, naphthol novolak resin,
Various phenols, hydroxybenzaldehyde,
Epoxy resins produced from various phenolic compounds such as polyhydric phenol resins obtained by condensation reaction with various aldehydes such as crotonaldehyde and glyoxal, and epihalohydrin; various kinds of epoxy resins such as diaminodiphenylmethane, aminophenol, xylenediamine And an epoxy resin produced from an epihalohydrin.

The proportion of the (a) disubstituted biphenol type epoxy resin in all epoxy resins in the epoxy resin composition of the present invention is preferably at least 50% by weight. If the proportion of the epoxy compound of the present invention is too small, the effects of the present invention (an effect of giving a cured product having high heat resistance, low moisture absorption and excellent low stress, and excellent reactivity) can be sufficiently exerted. Disappears.

Further, the epoxy resin composition of the present invention comprises:
(B) The composition contains a polyhydric phenol resin as a curing agent.
A resin having an average of two or more phenolic hydroxyl groups in the molecule, such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, biphenol novolak resin, dicyclopentadiene phenol resin, terpene phenol resin, and phenol aralkyl resin. And various phenol resins such as polyhydric phenol resins obtained by a condensation reaction of various phenols with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde and glyoxal.

(B) The amount of the polyhydric phenol resin to be used is such that the phenolic hydroxyl group in the polyhydric phenol resin is 0.5-2.
The amount is preferably 0 mol, more preferably 0.7 to 0.7 mol.
1.2 mol.

The epoxy resin composition for sealing of the present invention comprises:
If necessary, a curing accelerator, a filler, a coupling agent, a flame retardant, a plasticizer, a pigment, and the like can be appropriately compounded.

As the curing accelerator, for example, 2-
Imidazoles such as methylimidazole and 2-ethyl-4-methylimidazole; amines such as 2,4,6-tris (dimethylaminomethyl) phenol and benzyldimethylamine; tributylphosphine, triphenylphosphine, tris (dimethoxyphenyl) And organic phosphorus compounds such as phosphine.

Examples of the filler include fused silica, crystalline silica, glass powder, alumina, zircon and the like.

Examples of the flame retardant include antimony trioxide, phosphoric acid, and the like. The flame retardant can also be obtained by using a part of the epoxy resin used as the brominated epoxy resin.

The epoxy resin composition of the present invention has a high heat resistance, gives a cured product excellent in low moisture absorption and low stress properties, and is excellent in reactivity as compared with conventional epoxy resin compositions. It can be used advantageously in the field of sealing.

[0030]

The present invention will be described in more detail with reference to production examples, examples and comparative examples of disubstituted biphenol type epoxy resins.

Production example 1 of di-substituted biphenol type epoxy resin: 3000 ml in content equipped with thermometer, stirrer and cooling tube
3,3'-dimethyl-4,4'-
214 g of biphenol, 1295 epichlorohydrin
g and 504 g of isopropyl alcohol.
After heating to 5 ° C. and dissolving uniformly, 48.5% by weight
190 g of an aqueous sodium hydroxide solution was added dropwise over 1 hour. During this time, the temperature gradually rises, and at the end of dropping,
The temperature was adjusted to 5 ° C. Thereafter, the reaction was carried out at 65 ° C. for 30 minutes. After the completion of the reaction, the product was washed with water to remove by-product salts and excess sodium hydroxide. Next, excess epichlorohydrin and isopropyl alcohol were distilled off from the product under reduced pressure to obtain a crude epoxy resin.

This crude epoxy resin was dissolved in 500 g of methyl isobutyl ketone, 6 g of a 48.5% by weight aqueous sodium hydroxide solution was added, and the mixture was reacted at a temperature of 65 ° C. for 1 hour. After the completion of the reaction, sodium phosphate monobasic was added to neutralize the excess sodium hydroxide, and washed with water to remove by-product salts. Next, methyl isobutyl ketone was completely removed under reduced pressure to obtain a dimethyl biphenol epoxy resin.

This epoxy resin has an epoxy equivalent of 171
g / eq. , A yellow-white solid having a melting point of 122 ° C.

Production Example 2 of di-substituted biphenol type epoxy resin In place of 214 g of 3,3'-dimethyl-4,4'-biphenol used in Production Example 1, 3,3'-dibutyl-4,4
Using 298 g of 4'-biphenol, it was reacted with epichlorohydrin in the same manner as in Preparation Example 1 and worked up to give an epoxy equivalent of 220 g / eq. Thus, a semi-solid di-substituted biphenol epoxy resin was obtained.

Examples 1 to 3 Comparative Examples 1 and 2 As shown in Table 1, each of the disubstituted biphenol type epoxy resins obtained in Preparation Examples 1 and 2 of the disubstituted biphenol type epoxy resin, tetramethyl biphenol Type epoxy resin, or ortho-cresol novolak type epoxy resin, phenol novolak resin or terpene phenol resin as a curing agent, brominated epoxy resin and antimony trioxide as a flame retardant, triphenylphosphine as a curing accelerator, silica as a filler Each epoxy resin composition was compounded using powder and epoxy silane as a surface treatment agent, and carnauba wax as a release agent.

Next, each composition was melt-mixed for 5 minutes at a temperature of 80 to 130 ° C. using a mixing roll. Each of the obtained molten mixtures was taken out in a sheet shape and pulverized to obtain each semiconductor sealing material.

Using each of these semiconductor encapsulating materials, a mold temperature of 180 ° C. and a molding time of
44-pin FPP molded in 0 seconds and sealed with glass transition temperature measurement test piece, moisture absorption measurement test piece and simulated element
(Flat plastic package) was obtained and post-cured at 180 ° C. for 8 hours.

The gel time of each semiconductor encapsulating material and
The results of testing the glass transition temperature, moisture absorption and solder heat resistance after the post cure are as shown in Table 1.
Each of the semiconductor encapsulating materials of Examples 1 to 3 is superior in reactivity (short gel time), has a high glass transition temperature, has a low moisture absorption rate, as compared with the semiconductor encapsulating materials of Comparative Examples 1 and 2. A cured product having excellent solder heat resistance was provided. It is considered that the excellent solder heat resistance is due to the low stress property, low moisture absorption property and high glass transition temperature of these molding materials, which were suitable for semiconductor encapsulation.

[0039]

[Table 1]

Notes on Table 1: * 1 ... Yuka Ciel Epoxy Co., Ltd. Epicoat 18
0H65, epoxy equivalent 201, softening point 67 ° C * 2 ... Yuka Ciel Epoxy Co., Ltd. Epicoat YX
4000H, epoxy equivalent 193 * 3 ... Yuka Ciel Epoxy Co., Ltd. Epicoat 50
50, epoxy equivalent 385, bromine content 49% * 4: Gunei Chemical Co., softening point 85 ° C * 5: Yuka Ciel Epoxy Co., Ltd.
LH402, hydroxyl equivalent 170, softening point 125 ° C * 6 Tatsumori company name RD-8 * 7 Shin-Etsu Chemical company name KBM-403 * 8 150 ° C * 9 TMA Was determined from the transition point of the thermal expansion curve. * 10: Moisture absorption after 168 hours at 85 ° C and 85% RH * 11: After absorbing 16 pieces of 44-pin FPP for 168 hours at 85 ° C and 85% RH, immersed in a 260 ° C solder bath for 10 seconds to remove cracks. The number of occurrences was determined.

[0041]

The epoxy resin composition of the present invention has high heat resistance, can give a cured product having excellent low moisture absorption and low stress, and has excellent reactivity, and is therefore advantageous in the field of semiconductor encapsulation. Can be used for

──────────────────────────────────────────────────の Continuation of the front page (72) Inventor Yoshinori Nakanishi 1, Shiohama-cho, Yokkaichi-shi, Mie Yuka-Chell Epoxy Co., Ltd. (56) References JP-A-4-50257 (JP, A) 3-285910 (JP, A) JP-A-3-239718 (JP, A) JP-A-63-41527 (JP, A) JP-A-5-97972 (JP, A) JP-A-3-66723 (JP, A A) JP-A-3-14818 (JP, A) JP-A-2-258831 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 59/24 C08G 59/62 H01L 23 / 29

Claims (1)

(57) [Claims] (A) a general formula: (Wherein, R ¹ and R ² are each an alkyl group having 1 to 10 carbon atoms or a phenyl group, and n is a number of 0 to 5 on average), and (B) An epoxy resin composition for sealing, comprising a polyhydric phenol resin as an essential component.