JPH1160902A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition for semiconductor sealing that shows good curing properties and has excellent fluidity and moisture resistance by allowing the resin composition to include an epoxy resin, a phenolic resin and a specific organic phosphorane. SOLUTION: The objective resin composition includes 100 pts.wt., in total, of (A) an epoxy resin as a cresol-novolak type epoxy resin and (B) a phenolic resin as a curing agent such as phenol novolak resin in an amount that the hydroxyl groups in the component B becomes 0.5-2.0 to the equivalent amount of the epoxy group in time component A, (C) 0.1-20 pts.wt., per 100 pts.wt. of the resin components A and B of an organophosphorane of formula I (at least one of the substituents R<1> -R<3> is an electro-donating group-substituted aralkyl or aryl; R<4> and R<5> are each H, a monovalent organic group or an organic group which forms a ring structure together with one carbon atom), for example, a compound of formula II, and contains, (D) when necessary, an inorganic filler, a silane coupling agent, a mold releasing agent, a flame- retardant, pigments and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD [0001] The present invention has good curability,
The present invention also relates to an epoxy resin composition for semiconductor encapsulation having excellent fluidity and moisture resistance.

[0002]

2. Description of the Related Art Generally, a catalyst is added to an epoxy resin composition for semiconductor encapsulation in order to promote curing during molding. However, this catalyst has a problem of deteriorating the quality of the resin composition because it exhibits a curing acceleration effect even at a low temperature of about room temperature. That is, IC
When performing encapsulation molding of semiconductor elements and electric components such as semiconductors and LSIs, there is a problem that poor filling due to a decrease in fluidity during molding, breakage of gold wires of IC chips, poor conduction, etc. . For example, imidazole compounds, amines, nitrogen-containing heterocyclic compounds, organic phosphine compounds, etc. are used as curing catalysts, but storage at low temperature during storage and transportation, management when mixing with various components, and strict molding conditions The troublesome work for quality control after production, such as quality, could not be avoided.

In order to improve the storage stability, in recent years, studies have been made to make the catalytic activity latent so that it does not show activity at a relatively low temperature of about room temperature, but shows activity only at the time of molding and heating. For example, there are techniques such as microencapsulation and chemical modification.

[0004] The currently most effective of these approaches is the quaternary phosphonium conversion of tertiary phosphines. Actually, the use of a tetra-substituted phosphonium borate salt or an organic acid salt as a catalyst provides a resin composition having good storage stability, excellent fluidity during molding, and excellent curability. It is known among traders. However, since the catalyst has a salt structure, free anions adversely affect moisture resistance when dispersed in a resin matrix, causing corrosion of IC chips. Therefore, development of a non-salt catalyst having no ionic structure as a catalyst is required. As an example, JP-A-7-228671
In the publication, there is exemplified a non-salt type alkylidenetriphenylphosphorane, but the phosphorus-side substituent is limited to a phenyl group.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made as a result of various studies to overcome the above-mentioned problems, and has been found to be a semiconductor encapsulation which has good curability and excellent fluidity and moisture resistance. It is an object to provide an epoxy resin composition for stopping.

[0006]

The present inventors have conducted various studies on the phosphorus-side substituent of an organic phosphorane, and as a result, have found that an organic phosphorane having an aralkyl group or an aryl group substituted with an electron donating group on a phosphorus atom can be used as a catalyst. It has been found that by using such a resin, an epoxy resin composition for semiconductor encapsulation having good curability and excellent fluidity and moisture resistance can be obtained, and the present invention has been completed.

That is, the present invention is a resin composition comprising, as essential components, an epoxy resin, a phenol resin, and an organic phosphorane represented by the general formula (1).

Embedded image In the formula, at least one of the substituents R ^{1 to} R ³ is an aralkyl group or an aryl group substituted with an electron donating group, which may be the same or different. R ⁴
And R ⁵ are a hydrogen atom, a monovalent organic group, or an organic group forming a cyclic structure together with C ¹ , and may be the same or different.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention is not particularly limited as long as it has an epoxy group in a molecule. For example, bisphenol A epoxy resin, bisphenol F epoxy resin, Bisphenol AD epoxy resin, brominated epoxy resin, biphenyl epoxy resin, phenol novolak epoxy resin, cresol novolak epoxy resin, cycloaliphatic epoxy resin, glycidyl ester epoxy resin, glycidylamine epoxy resin, trifunctional epoxy resin Resins (eg, trishydroxyphenylmethane type epoxy resin, triglycidyl isocyanate resin), stilbene type epoxy resin, and phenol resin synthesized by condensation reaction of dicyclopentadiene and phenol Epoxy obtained by ether resin, and naphthalene type epoxy resin, various epoxy resins conventionally used for sealing of semiconductor devices can be used.

The phenolic resin used in the present invention comprises:
It acts as a curing agent for the epoxy resin. The general definition of phenol is the substitution of a hydrogen atom on the aromatic ring with a hydroxyl group in an aromatic molecule such as benzene, naphthalene, or ferrocene, and the condensation of a compound defined as phenol with a carbonyl compound. The product is a phenolic resin. Examples of the phenolic resin used in the present invention include, for example, phenol novolak resin, cresol novolak resin, t-butylphenol novolak resin, nonylphenol novolak resin, novolak type modified phenol resin such as phenol aralkyl resin, resol type phenol resin, polyparaoxystyrene. Such as polyoxystyrene resin and naphthol resin. The mixing ratio of the epoxy resin and the phenol resin is preferably such that the hydroxyl group in the phenol resin is 0.5 to 2.0 per equivalent of the epoxy group in the epoxy resin. Outside of this range,
In some cases, sufficient curability may not be obtained.

Further, the organic phosphorane used in the present invention is represented by the above general formula (1). General formula (1)
In the formula ( ¹⁾ , at least one of the organic groups represented by R ^{1 to} R ³ may be an aralkyl group or an aryl group substituted with an electron donor. The electron donating group mentioned here can be said to be a substituent having a negative value of σP-X if Hammett's concept is adopted (Tokyo Kagaku Doujin “Organic Reaction Mechanism”, 5th edition, 377- 381). Specifically, for example, an alkoxybenzyl group, an alkoxyphenyl group, a hydroxyphenyl group, an aminophenyl group, a tolyl group, an alkoxynaphthyl group and the like are generally used, but they may be the same or different.

R ⁴ and R ⁵ may be hydrogen atoms or monovalent organic groups, and may be the same or different. Specifically, an alkyl group, an aralkyl group, an aryl group, an acyl group, a formyl group, a carboxyl group, an ester group, a cyano group, and the like are suitable in terms of handling and supply of raw materials. R ⁴ and R ⁵ may further form a cyclic structure together with C ¹ , which is preferable since the phosphorus ylide structure becomes stable on the skeleton. Specific examples include a cycloalkane structure such as cyclopentane and cyclohexane, a cycloalkene structure such as cyclopentadiene and cyclohexadiene, and a fluorene structure.

The amount of the organic phosphorane is 0.1 parts by weight based on 100 parts by weight of the total of the epoxy resin and the phenol resin.
It is preferable to use in the range of 20 to 20 parts by weight. If the amount of the organic phosphorane is less than 0.1 part by weight, a sufficient curing promoting effect cannot be obtained. Conversely, if it exceeds 20 parts by weight, the fluidity and moisture resistance during molding may be reduced.

[0013] In addition to the essential components of epoxy resin, phenolic resin and organic phosphorane, the resin composition of the present invention may further contain an inorganic filler, a silane coupling agent, a release agent, Additives known to those skilled in the art, such as flame retardants and pigments, can be added.

[0014]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The structures of the resin and the catalyst (organophosphorane) used in Examples and Comparative Examples are as follows.

[0015]

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[0016]

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[0017]

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[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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(Examples 1 to 6 and Comparative Examples 1 to 3) A molding material was prepared, and its spiral flow and residual flow rate, hardening torque, and pressure cooker test were performed to evaluate its properties. Was. Each evaluation method was as follows.

(1) Spiral flow Using a mold for measuring spiral flow according to EMMI-I-66, a mold temperature of 175 ° C. and an injection pressure of 70 kg / c.
The measurement was performed under the conditions of m ² and curing time of 2 minutes. Spiral flow is a parameter of the flowability of a molding material, and a larger value indicates a higher flowability.

(2) Remaining flow rate Spiral flow immediately after preparing the material, and 30
The spiral flow after storage at 7 ° C. for 7 days was measured, and the percentage of the spiral flow value (cm) after storage relative to the spiral flow value (cm) immediately after material preparation was determined. The larger the value, the better the preservability.

(3) Curing Torque Using a curastometer (manufactured by Orientec Co., Ltd., JSR curastometer IVPS type) at 175 ° C. and 45 ° C.
The torque after seconds was measured. The torque in the curast meter is a parameter of curability, and a larger value indicates higher curability.

(4) Pressure cooker test (PC
T) A 16pDIP equipped with a test element was molded at 175 ° C for 2 minutes, post-cured at 175 ° C for 8 hours, and subjected to a moisture resistance test in an autoclave at 125 ° C and 2.3 atmospheres. did. The defect judgment is 5 when n = 10.
The time when the individual conduction failure occurred was defined as a 50% failure occurrence time. The longer the 50% failure occurrence time, the better the moisture resistance.

(Example 1) Orthocresol novolak type epoxy resin (EOCN-1025 manufactured by Nippon Kayaku Co., Ltd.)
-65, softening point 65 ° C, epoxy equivalent 210) 67 parts by weight, phenol novolak resin (Sumitomo Durez Co., Ltd.)
Manufacture, PR-51470, softening point 105 ° C, hydroxyl equivalent 1
04), 33 parts by weight of an organic phosphorane represented by the formula (4) as a catalyst, 300 parts by weight of crushed fused silica, and 2 parts by weight of carnauba wax.
For 8 minutes to obtain a molding material. The spiral flow of this molding material is 79cm and the curing torque is 85kgf
-In cm, the flow residual rate was 91%. Also, PC
In the T humidity resistance test, no failure occurred up to 2000 hours.

(Example 2) 52 parts by weight of an epoxy resin represented by the formula (2) (YX4000H, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 187 to 197) and a phenol resin represented by the formula (3) were used. 48 parts by weight, as a catalyst, formula (5)
Was mixed with 2.6 parts by weight of the organic phosphorane represented by the formula, 800 parts by weight of spherical fused silica, and 3 parts by weight of carnauba wax, and the same operation as in Example 1 was carried out to obtain a molding material. The spiral flow of the obtained material was 82 cm, the curing torque was 84 kgf · cm, and the residual flow rate was 80%.
Further, in the PCT humidity resistance test, no failure occurred up to 2000 hours.

(Example 3)
A molding material was obtained by blending and operating in the same manner as in Example 1, except that 1.8 parts by weight of the organic phosphorane represented by (6) was used. The spiral flow of the obtained material was 80 cm, the curing torque was 80 kgf · cm, and the residual flow rate was 93%. Further, in the PCT moisture resistance reliability test, 200
No failure occurred until 0 hour.

(Example 4)
A molding material was obtained in the same manner as in Example 2 except that 2.7 parts by weight of the organic phosphorane represented by (7) was used. The spiral flow of the obtained material was 85 cm, the curing torque was 81 kgf · cm, and the residual flow rate was 82%. In the PCT moisture resistance reliability test, 2000
No failures occurred until time.

(Example 5) In Example 1, the catalyst was replaced with a compound represented by the formula
A molding material was obtained by blending and operating in the same manner as in Example 1, except that 2.0 parts by weight of the organic phosphorane represented by (8) was used. The spiral flow of the obtained material was 81 cm, the curing torque was 85 kgf · cm, and the residual flow rate was 90%. Further, in the PCT moisture resistance reliability test, 200
No failure occurred until 0 hour.

Example 6 In Example 2, the catalyst was replaced with a compound represented by the formula
A molding material was obtained by blending and operating in the same manner as in Example 2 except that 2.4 parts by weight of the organic phosphorane represented by (9) was used. The spiral flow of the obtained material was 78 cm, the curing torque was 80 kgf · cm, and the residual flow rate was 79%. Further, in the PCT moisture resistance reliability test, 200
No failure occurred until 0 hour.

Comparative Example 1 A molding material was obtained in the same manner as in Example 1, except that the catalyst was changed to 0.8 parts by weight of triphenylphosphine. The resulting material has a spiral flow of 77 cm and a curing torque of 35.
At kgf · cm, the residual flow rate was 51%. The 50% failure occurrence time of the PCT humidity resistance test was 1
200 hours.

Comparative Example 2 In Example 2, the catalyst was tetraphenylphosphonium tetraphenylborate (T
PP-K) A molding material was obtained by blending and operating in the same manner as in Example 2 except that the amount was changed to 4.5 parts by weight. The resulting material has a spiral flow of 84 cm and a curing torque of 41 kgf · c.
m, the residual flow rate was 85%. The 50% failure occurrence time in the PCT humidity resistance test was 500 hours.

(Comparative Example 3) In Example 1, the catalyst was
A molding material was obtained by compounding and operating in the same manner as in Example 1 except that 2.1 parts by weight of the organic phosphorane represented by (10) was used. The spiral flow of the obtained material was 78 cm, the curing torque was 63 kgf · cm, and the residual flow rate was 86%. In the PCT moisture resistance reliability test, 2000
No failures occurred until time.

The compositions and evaluation results of Examples and Comparative Examples are summarized in Table 1. The resin composition of the present invention containing an organic phosphorane as a catalyst (Examples 1 to 3)
6) shows a large spiral flow value immediately after production, good fluidity, and a residual flow rate of 80% or more, and has storage stability equal to or higher than that of the conventional catalyst. You can see that. At the same time, it can be seen that the curing torque value is high and the reactivity during heating and molding is excellent. In addition, since the PCT 50% failure occurrence time was at a level exceeding 2000 hours, it can be said that the moisture resistance was excellent.

On the other hand, in Comparative Example 1, although the fluidity shows a good value, the flow residual ratio shows a low value of 60% or less, which is problematic in storage stability. In Comparative Example 2,
The fluidity and storage stability are good, but the PCT 50% failure occurrence time is 1000 hours or less, and the moisture resistance is not good.
Further, Comparative Example 3 is excellent in fluidity, storage stability, and moisture resistance, but is insufficient in curability.

[0040]

[Table 1]

[0041]

The epoxy resin composition according to the present invention is excellent in so-called curability and hardly undergoes a curing reaction at about room temperature, so that it can be stably stored for a long period of time. This is to improve the curability by introducing an electron donating substituent on the phosphorus atom of the organic phosphorane, and because the catalyst has a non-salt structure,
Provides a material with excellent moisture resistance. In particular, it is useful as a resin composition for a semiconductor sealing material.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 23/31 (72) Inventor Go Endo 54-13 Miyagaya, Nishi-ku, Yokohama-shi (72) Inventor Fumio Mita Hino, Konan-ku, Yokohama-shi 6-11-15-301

Claims (3)

[Claims] 1. A resin composition comprising, as essential components, an epoxy resin, a phenol resin, and an organic phosphorane represented by the general formula (1). Embedded image In the formula, at least one of the substituents R ^{1 to} R ³ is an aralkyl group or an aryl group substituted with an electron donating group, which may be the same or different. R ⁴
And R ⁵ are a hydrogen atom, a monovalent organic group, or an organic group forming a cyclic structure together with C ¹ , and may be the same or different. 2. The organic phosphorane represented by the general formula (1), wherein the substituents R ⁴ and R ⁵ are an alkyl group, an aralkyl group,
Aryl group, acyl group, formyl group, carboxyl group,
The resin composition according to claim 1, wherein the resin composition is one or two selected from an ester group and a cyano group. 3. The cyclic structure formed by the substituents R ⁴ and R ^{5 of the} organophosphorane represented by the general formula (1) together with C ¹ is one of a cycloalkane structure, a cycloalkene structure and a fluorene structure. The resin composition according to claim 1, wherein: