JPH1160903A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition for semiconductor sealing that shows good storage stability, and has excellent fluidity, curing properties 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 the 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 electron-attracting 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]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation having good storage stability, excellent fluidity, and excellent curability and moisture resistance.

[0002]

2. Description of the Related Art Generally, a catalyst is added to an epoxy resin composition for encapsulating a semiconductor in order to accelerate 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, when performing encapsulation molding of semiconductor elements and electric components of ICs and LSIs, there are problems such as defective filling due to a decrease in fluidity during molding, disconnection of gold wires of IC chips, and poor conduction. . For example, imidazole compounds, amines, nitrogen-containing heterocyclic compounds, organic phosphine compounds, etc. are used as curing catalysts, but storage at low temperatures during storage and transportation, management during mixing with various components, and strictness of molding conditions Such troublesome efforts for quality control after production cannot 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. In fact, by using a borate salt or an organic acid salt of a tetra-substituted phosphonium as a catalyst, it is possible to obtain 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 IC chip corrosion. 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 alkylidene triphenylphosphorane, 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 problems, and has good storage stability, excellent fluidity, curability and moisture resistance. An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation having excellent properties.

[0006]

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

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

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-withdrawing 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 the molecule. For example, bisphenol A type epoxy resin, bisphenol F type 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 For example, trishydroxynphenylmethane type epoxy resin, triglycidyl isocyanate resin, stilbene type epoxy resin, and phenol resin synthesized by condensation reaction of dicyclopentadiene with phenols Such as epoxy resins and naphthalene type epoxy resin obtained by Jill etherified, 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. As the phenolic resin used in the present invention, for example, a phenolic novolak resin, a cresol novolak resin, a t-butylphenol novolak resin, a nonylphenol novolak resin, a novolak-modified phenol resin such as a phenol aralkyl resin,
Examples thereof include a resol type phenol resin, a polyoxystyrene resin of polyparaoxystyrene, and a 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 the above range, 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 above, 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-withdrawing group. The electron withdrawing group referred to here can be said to be a substituent having a positive value of σ _PX if Hammett's concept is adopted (Tokyo Kagaku Doujin “Organic Reaction Mechanism”, 5th edition, 377-381). Page). Specific examples include a halogenated phenyl group, a nitrophenyl group, a cyanophenyl group, an acetophenyl group, and the like, which 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 effect promoting effect cannot be obtained. Conversely, if it exceeds 20 parts by weight, a decrease in fluidity and moisture resistance during molding may be observed.

[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 a spiral flow and a residual flow rate, a curing torque, and a 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 adjusting the material, and 30
The spiral flow after storage at ゜ C for 15 days was measured, and the percentage of the spiral flow value (cm) after storage with respect to the spiral flow value (cm) immediately after the material preparation was determined. The larger the value, the better the preservability.

(3) Curing torque Curast meter (Orientec Co., Ltd., JSR
Curastometer IVPS), 175 ° C, 9
The torque after 0 seconds was determined. 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 mounted 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 atm. Carried out. 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 (manufactured by Nippon Kayaku Co., Ltd., EOCN-102)
5-65, softening point 65 ° C, epoxy equivalent 210) 67
33 parts by weight of a phenol novolak resin (manufactured by Sumitomo Durez Co., Ltd., PR-51470, softening point 105 ° C, hydroxyl equivalent 104), and 1.8 parts by weight of an organic phosphorane represented by the formula (4) as a catalyst. , Fused silica 300
Parts by weight and 2 parts by weight of carnauba wax, 90
Roll kneading was performed at 8 ° C. for 8 minutes to obtain a molding material. The spiral flow of this molding material is 81cm and the curing torque is 76kg
At f · cm, the residual flow rate was 89%. Also,
In the PCT moisture resistance reliability test, no failure occurred up to 2000 hours.

Example 2 An epoxy resin represented by the formula (2) (YX4000H, manufactured by Yuka Shell Epoxy Co., Ltd.)
52 parts by weight of the epoxy equivalent (187 to 197), formula (3)
48 parts by weight of a phenolic resin represented by the formula, 2.5 parts by weight of an organic phosphorane represented by the formula (5) as a catalyst, 800 parts by weight of spherical fused silica, and 3 parts by weight of carnauba wax were mixed. The same operation was performed to obtain a molding material. The spiral flow of the obtained material was 79 cm, the curing torque was 82 kgf · cm, and the flow residual ratio was 80%. In the PCT moisture resistance reliability test, 2000
No failures occurred until time.

Example 3 A molding material was obtained in the same manner as in Example 1 except that the catalyst was replaced by 1.9 parts by weight of the organic phosphorane represented by the formula (6). Was. The spiral flow of the obtained material was 84 cm, the curing torque was 80 kgf · cm, and the flow residual ratio was 90%. In the PCT moisture resistance reliability test, 2000
No failures occurred until time.

Example 4 A molding material was obtained in the same manner as in Example 1 except that the catalyst was replaced by 2.3 parts by weight of the organic phosphorane represented by the formula (7). Was. The spiral flow of the obtained material was 80 cm, the curing torque was 86 kgf · cm, and the residual flow rate was 82%. In the PCT moisture resistance reliability test, 2000
No failures occurred until time.

Example 5 A molding material was obtained by blending and operating in the same manner as in Example 1 except that the catalyst was changed to 1.8 parts by weight of the organic phosphorane represented by the formula (8). Was. The spiral flow of the obtained material was 77 cm, the curing torque was 79 kgf · cm, and the residual flow rate was 92%. In the PCT moisture resistance reliability test, 2000
No failures occurred until time.

Example 6 A molding material was obtained by blending and operating in the same manner as in Example 1 except that the catalyst was changed to 2.6 parts by weight of the organic phosphorane represented by the formula (9). Was. The spiral flow of the obtained material was 82 cm, the curing torque was 83 kgf · cm, and the residual flow rate was 83%. In the PCT moisture resistance reliability test, 2000
No failures occurred until time.

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 79 cm and a curing torque of 74.
At kgf · cm, the residual flow rate was 33%. The 50% failure occurrence time of the PCT humidity resistance test was 1
100 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 1 except that 3.9 parts by weight was used. The spiral flow of the obtained material is 87 cm, and the curing torque is 83 kgf · c.
m, the residual flow rate was 73%. The 50% failure occurrence time in the PCT humidity resistance test was 600 hours.

Comparative Example 3 A molding material was obtained by blending and operating in the same manner as in Example 1 except that the catalyst was changed to 2.0 parts by weight of the organic phosphorane represented by the formula (10). Was. The spiral flow of the obtained material was 80 cm, the curing torque was 81 kgf · cm, and the flow residual ratio was 70%. Further, in the PCT moisture resistance reliability test, 200
No failure occurred until 0 hour.

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) has good fluidity immediately after production and also shows an extremely high flow residual ratio, and thus can be said to be excellent in storage stability. In addition, the curing torque also showed a high value, and the PCT 50% failure occurrence time was at a level exceeding 2000 hours, so it can be said that the composition has excellent curability and moisture resistance.

On the other hand, in Comparative Example 1, although the fluidity and the curability show the same good values as in the Example, the flow remaining rate is 50%.
%, It can be said that there is a problem in storage stability. In Comparative Example 2, although the fluidity, curability, and storage stability were good, the PCT 50% failure occurrence time was 1000 hours or less, and the moisture resistance was poor. Compared with Comparative Example 3, the examples of the present invention showed improvement in storage stability while maintaining that the properties were equal or higher.

[0040]

[Table 1]

[0041]

The epoxy resin composition according to the present invention is excellent in so-called latent curability and hardly undergoes a curing reaction at about room temperature, so that it can be stably stored for a long period of time. By introducing an electron-withdrawing substituent on the phosphorus atom, storage stability could be improved. Also,
Since the catalyst has a non-salt structure, it provides a material having excellent moisture resistance, and is particularly useful as a semiconductor encapsulant.

──────────────────────────────────────────────────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-withdrawing 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: