JP2560469B2 - Epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an epoxy resin composition which is excellent in moldability and reliability and is particularly suitable for semiconductor encapsulation.

<Prior art> Epoxy resin is excellent in heat resistance, moisture resistance, electrical characteristics and adhesiveness, and can be given various characteristics by blending formulation, so it is used as an industrial material such as paints, adhesives and electrical insulation materials. Has been done.

For example, as a method of sealing electronic circuit parts such as semiconductor devices, hermetic sealing using metal or ceramics and resin sealing using phenol resin, silicone resin, epoxy resin, etc. have been proposed. However, resin sealing with an epoxy resin is mainly used from the viewpoint of the balance of economy, productivity and physical properties.

As a sealing method using an epoxy resin, a method in which a semiconductor element is set in a metal mold using a composition obtained by adding a curing agent, a filler, etc. to an epoxy resin and sealing is performed by a transfer molding method or the like is generally performed. It is being appreciated.

The characteristics required of the epoxy resin composition for sealing include reliability and moldability, and reliability includes moisture resistance, and moldability includes fluidity, hot hardness, burr, and the like. .

The term “moisture resistance” here means that when a resin-encapsulated semiconductor is left in a high-temperature, high-humidity environment, moisture enters through an interface between the encapsulation resin and the encapsulation resin and the lead frame,
This is to prevent the semiconductor from breaking down, and in recent years, the degree of integration of the semiconductor has been improved and higher moisture resistance has been required.

In order to improve the moisture resistance of the sealing resin, a silane coupling agent is usually added. Specifically, a method of adding epoxy silane (Japanese Patent Publication No. 62-17640), a method of adding mercaptosilane (JP-A-55-153357) and a method of adding aminosilane having a primary amino group (JP-A-57-155753) have been proposed.

Further, it is possible to improve the moisture resistance by reducing impurities contained in components such as an epoxy resin and a curing agent and making the sealing resin highly purified (JP-A-57-212224).
Is also proposed.

<Problems to be Solved by the Invention> However, addition of a silane coupling agent to the encapsulating resin is effective for improving the moisture resistance, but in order to deal with highly integrated semiconductors. Has further been required to have a high degree of moisture resistance, and it has become clear that conventional silane coupling agents are not sufficient.

In addition, the method of adding an aminosilane having a primary amino group, which has been conventionally used, improves the moisture resistance and at the same time improves the hardness at the time of heating and also exhibits the effect of improving the moldability such as reducing the burr. It was not practical because the fluidity deteriorated.

On the other hand, reducing the impurities such as the epoxy resin and the curing agent to highly purify the sealing resin is effective for improving the moisture resistance, but there is a problem that there is a limit to the high purification of the sealing resin. there were.

Then, the subject of this invention solves the problem which the above-mentioned epoxy resin composition has, and provides an excellent resin composition in which reliability such as moisture resistance and fluidity, hot hardness, moldability such as burr are balanced. By doing so, it is possible to realize a highly integrated resin-sealed semiconductor.

<Means for Solving the Problems> The present inventors can achieve the above-mentioned problems by adding a silane coupling agent having a specific structure,
The present invention has been accomplished by finding that an epoxy resin composition that meets the purpose can be obtained.

That is, the present invention is an epoxy resin composition comprising an epoxy resin (A), a curing agent (B), a filler (C) and a silane coupling agent (D), wherein the silane coupling agent (D) is An epoxy resin composition other than that represented by the following chemical formula (IV), which contains an amino group and contains a silane compound in which the amino groups are all secondary amino groups. An epoxy resin composition comprising an epoxy resin (A), a curing agent (B), a filler (C) and a silane coupling agent (D), wherein the proportion of the filler (C) is 75 to 90% by weight. %
90% to 40% by weight of crushed fused silica (C ') having an average particle size of 12 μm or less and an average particle size of 40 μm
The following fused silica (C ″) containing 10 to 60% by weight of fused silica (c), the silane coupling material (D) contains an amino group, and all the amino groups are secondary amino groups. An epoxy resin composition comprising a silane compound which is

(In the above formula, R is a methyl group or an ethyl group, n is 0 or 1. In addition, a, b, and c are positive integers.) The constitution of the present invention will be described in detail below.

The epoxy resin (A) in the present invention is not particularly limited as long as it has two or more epoxy groups in one molecule, and specific examples thereof include, for example, cresol novolac type epoxy resin and bishydroxybiphenyl type epoxy resin. , Bisphenol A type epoxy resin, linear aliphatic type epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, halogenated epoxy resin and spiro ring-containing epoxy resin.

Depending on the application, two or more epoxy resins may be used together, but for semiconductor device encapsulation, the epoxy equivalent of cresol novolac type epoxy resin and bishydroxybiphenyl type epoxy resin is 500 in terms of heat resistance and moisture resistance. In the following, it is particularly preferable that the epoxy resin content of 300 or less is contained in an amount of 50% by weight or more in the total epoxy resin.

In the present invention, the compounding amount of the epoxy resin (A) is usually in the range of 5 to 25% by weight, and if it is less than 5% by weight, moldability and adhesiveness are insufficient, and if it exceeds 25% by weight, linear expansion occurs. This is not preferable because the coefficient becomes large and it becomes difficult to reduce the stress.

The curing agent (B) in the present invention is an epoxy resin (A)
It is not particularly limited as long as it reacts with and cures, and specific examples thereof include novolak resins such as phenol novolac and cresol novolac, bisphenol compounds such as bisphenol A, maleic anhydride, phthalic anhydride and pyropyrolic anhydride. Examples thereof include acid anhydrides such as mellitic acid and aromatic amines such as metaphenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone.

Among them, for semiconductor device encapsulation, in terms of heat resistance, moisture resistance and storage stability, novolac resins such as phenol novolac and cresol novolac are preferably used, and two or more curing agents are used in combination depending on the application. Good.

In the present invention, the amount of the curing agent (B) is usually from 2 to 15
% By weight.

Further, the compounding ratio of the epoxy resin (A) and the curing agent (B) is such that the chemical equivalent ratio of (B) to (A) is 0.5 to 1.6, particularly 0.8 to 1.3 from the viewpoint of mechanical properties and moisture resistance. Is preferred.

In the present invention, a curing catalyst may be used to accelerate the curing reaction between the epoxy resin (A) and the curing agent (B). The curing catalyst is not particularly limited as long as it accelerates the curing reaction, and for example, 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl. Imidazole, imidazole compounds such as 2-heptadecyl imidazole, triethylamine, benzyldimethylamine, α-methylbenzylmethylamine, 2-
Tertiary amine compounds such as (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,0) undecene-7, zirconium tetramethoxide, zirconium tetra Organometallic compounds such as propoxide, tetrakis (acetylacetonato) zirconium, tri (acetylacetonato) aluminum and triphenylphosphine,
Examples thereof include organic phosphine compounds (F) such as trimethylphosphine, triethylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine and tri (nonylphenyl) phosphine. Among them, the organic phosphine compound (F) is preferable and triphenylphosphine is particularly preferably used from the viewpoint of reliability and moldability.

Two or more kinds of these curing catalysts may be used in combination depending on the use, and the addition amount thereof is preferably in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the epoxy resin (A).

Examples of the filler (C) in the present invention include fused silica (c), crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, asbestos and glass fiber. . Of these, the fused silica (c) has a large effect of lowering the linear expansion coefficient and is effective in reducing the stress, and is therefore preferably used. Further, the proportion of the filler (C) is 75 to 90% by weight of the whole, and the filler (C) has an average particle size of 12
The inclusion of fused silica (c) consisting of 90 to 40% by weight of crushed fused silica (C ′) having a particle size of less than or equal to 10 μm and 10 to 60% by weight of spherical fused silica (C ″) having an average particle size of 40 μm or less, It is preferable in terms.

Here, the average particle diameter means a particle diameter (median diameter) at which the cumulative weight becomes 50%.

As the silane coupling agent (D) in the present invention, it is important to use a silane compound containing an amino group, and the amino groups are all secondary amino groups.

Specific examples of these silane coupling agents (D) include those represented by the following formula (I) or (II).

(R ¹ , R ² and R ³ are monovalent hydrocarbon groups having 1 to 20 carbon atoms, R ⁴ and R ⁵
Represents a divalent hydrocarbon group having 1 to 20 carbon atoms, and n represents an integer of 1 to 3, respectively. Among them, in the formula (I), a silane coupling agent (D) in which R ¹ is a phenyl group, R ² and R ³ are methyl groups and / or ethyl groups, R ⁴ is a propylene group, and n is 2 or 3 is formed. Since it has a great effect of improving the reliability and reliability, it is preferably used.

The amount of the silane coupling agent (D) added is usually 0.1 to 100 parts by weight of the filler in terms of moldability and reliability.
5 parts by weight, preferably 0.2 to 3 parts by weight, particularly preferably
0.3 to 1.5 parts by weight. Depending on the application, a silane coupling agent such as epoxysilane or mercaptosilane can be used in combination.

In the present invention, it is preferable in terms of reliability that the filler (C) is surface-treated in advance with a silane coupling agent (D) and a silane coupling agent such as epoxysilane or mercaptosilane.

In the present invention, a modified silicone oil (E) can be added to reduce stress and improve reliability.

The modified silicone oil (E) used here has an organopolysiloxane structure, and specific examples thereof include those represented by the following formula (III).

(R _{1 to} R ₅ are each one or more functional groups selected from hydrogen, an alkyl group having 1 to 20 carbon atoms, a phenyl group and a vinyl group, X,
Y is one or more groups selected from an alkyl group having 1 to 20 carbon atoms, a phenyl group, a vinyl group, an amino group, an epoxy group, a carboxyl group, a mercapto group, a polyoxyalkylene group, an alkoxy group and a fluorine atom and / or A functional group having atoms, Y may be hydrogen. Further, m represents an integer of 1 or more, and n represents an integer of 0 or more. However, it has a functional group having at least one group and / or atom selected from an amino group, an epoxy group, a carboxyl group, a mercapto group, a polyoxyalkylene group, an alkoxy group and a fluorine atom in the molecule. ) The modified silicone oil (E) is added in an amount of usually 0.01 to 5% by weight, preferably 0.1 to 5% in terms of stress reduction and reliability.
The range of 3 to 3% by weight, particularly 0.3 to 2% by weight is preferable.

The epoxy resin composition of the present invention includes a halogen compound such as a halogenated epoxy resin, a flame retardant such as a phosphorus compound, a flame retardant aid such as antimony trioxide, carbon black, a coloring agent such as iron oxide, a silicone rubber, Styrene-based block copolymers, olefin-based copolymers, modified nitrile rubber, modified polybutadiene rubber and other elastomers, polyethylene and other thermoplastic resins, titanate coupling agents and other coupling agents, long-chain fatty acids, long-chain fatty acid metals A salt, a long-chain fatty acid ester, a long-chain fatty acid amide, a releasing agent such as paraffin wax, and a cross-linking agent such as an organic peroxide can be optionally added.

The epoxy resin composition of the present invention is preferably melt-kneaded, and for example, produced by melt-kneading using a known kneading method such as a Banbury mixer, a kneader, a roll, a single-screw or twin-screw extruder and a cokneader. To be done.

<Examples> Hereinafter, the present invention will be specifically described with reference to Examples.

Examples 1 to 13 and Comparative Examples 1 and 2 In the formulation shown in Table 1, fused silica (c) shown in Table 2, silane coupling agent (D) shown in Table 3 and Table 4 The modified silicone oil (E) was dry blended with a mixer in the composition ratios shown in Tables 1 and 5, respectively. The mixture was heated and kneaded for 5 minutes using a mixing roll having a roll surface temperature of 90 ° C., cooled and pulverized to produce an epoxy resin composition.

Using this composition, the low-pressure transfer molding method
Molding was carried out under the conditions of 175 ° C. for 2 minutes, and spiral flow, resin flash and hot hardness were measured. The spiral flow was obtained by molding 30 g of the resin composition at a plunger speed of 25 m / sec using an EMMI type evaluation mold, and measuring the length. The resin flash was molded into a flash mold having a groove of 5 microns, and the length of the resin that entered the groove was the resin flash. Resin flash is equivalent to molding burr. In addition, a bending test piece is formed and 175
After post-curing at 5 ° C for 5 hours, the flexural modulus was measured according to ASTM D790 standard.

In addition, a 44-pin QFP encapsulating a simulated element is molded and 175
It was post-cured at ℃ × 5 hours.

For the measurement of reliability, post-cure 44pin QFP is used.
USPCBT was performed at 130 ° C, 85% RH, and bias voltage of 15V, and the time at which the cumulative failure rate became 50% was calculated.

The solder heat resistance was measured using post-cure 44pin QFP, after humidifying at 65 ° C and 95% RH for 24 hours, and then using a solder bath at 245 ° C for 5 hours.
After soaking for 2 seconds, the proportion of QFP in which no crack was generated was obtained.

 The results are shown together in Tables 5-7.

As shown in Table 5, the epoxy resin compositions (Examples 1 to 3) of the present invention are excellent in moldability and reliability such as spiral flow, resin flash, and hardness at the time of heating. In Examples 1 and 2 in which the organic phosphine compound (F) was added as, the reliability was particularly excellent.

On the other hand, the silane coupling agent (D) of the present invention
When not containing (Comparative Examples 1 and 2), moldability and reliability are poor.

Moreover, as seen in Table 5, the epoxy resin compositions (Examples 4 to 9) of the present invention containing 75 to 90% by weight of the filler (C) containing a specific fused silica are moldable and reliable. In addition, it has excellent solder heat resistance.

Further, as shown in Table 5, the epoxy resin compositions of the present invention (Examples 10 to 13) containing the modified silicone oil (E) have excellent moldability and further improved reliability, The flexural modulus is lowered and the stress is reduced.

<Effects of the Invention> The epoxy resin composition of the present invention has excellent moldability and reliability because it contains an epoxy resin, a curing agent, a filler, and a specific silane coupling agent, and is used for semiconductor encapsulation. It has ideal characteristics.

 ─────────────────────────────────────────────────── --- Continuation of front page (56) References JP-A-58-219218 (JP, A) JP-A-59-96122 (JP, A) JP-A-63-241061 (JP, A) JP-A-63- 251419 (JP, A) JP 59-75922 (JP, A) JP 57-155573 (JP, A) JP 2-210853 (JP, A)

Claims (10)

(57) [Claims] 1. An epoxy resin composition comprising an epoxy resin (A), a curing agent (B), a filler (C) and a silane coupling agent (D), wherein the silane coupling material (D) comprises: An epoxy resin composition other than that represented by the following chemical formula (IV), which contains an amino group and a silane compound in which all the amino groups are secondary amino groups. (In the above formula, R is a methyl group, n is 0 or 1, and a, b, and c are positive integers.) 2. The epoxy resin composition according to claim 1, wherein the silane compound in which all amino groups are secondary amino groups is represented by the following chemical formula (I) or (II). (R ¹ , R ² and R ³ are monovalent hydrocarbon groups having 1 to 20 carbon atoms, R ⁴ and
R ⁵ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, and n represents an integer of 1 to 3, respectively. ) 3. The epoxy resin composition according to claim 1 or 2, wherein the curing agent (B) contains a novolac resin as an essential component. 4. The proportion of the filler (C) is 75 to 90% by weight of the whole.
90% to 40% by weight of crushed fused silica (C ') having an average particle size of 12 μm or less and an average particle size of 40 μm
The spherical fused silica (C ″) below is contained in an amount of 10 to 60% by weight of fused silica (c).
(3) The epoxy resin composition according to any one of the above. 5. An epoxy resin composition comprising an epoxy resin (A), a curing agent (B), a filler (C) and a silane coupling agent (D), wherein the proportion of the filler (C) is. 90 to 40% by weight of crushed fused silica (C ') having an average particle size of 12 µm or less and 75 to 90% by weight of the filler (C) and spherical fused silica (C ") having an average particle size of 40 µm or less 10 ~
A silane compound containing 60 wt% of fused silica (c), wherein the silane coupling material (D) contains an amino group, and the amino group is a secondary amino group. Epoxy resin composition. 6. The epoxy resin composition according to any one of claims (1) to (5), wherein the composition further contains an organic phosphine compound (F). 7. The method for encapsulating a semiconductor (1) to (6).
The epoxy resin composition according to any of the above. 8. A semiconductor device encapsulated with the epoxy resin composition according to claim 7. 9. An epoxy resin (A), a curing agent (B), a filler (C) and an amino group other than those represented by the following chemical formula (IV), wherein the amino group is all two Silane coupling agent (D) containing a silane compound having a primary amino group
A method for producing an epoxy resin composition, which comprises melt-kneading. (In the above formula, R is a methyl group, n is 0 or 1, and a, b, and c are positive integers.) 10. An epoxy resin (A), a curing agent (B), 90 to 40% by weight of crushed fused silica (C ') having an average particle size of 12 μm or less and a spherical fused silica (C ″) 10 having an average particle size of 40 μm or less. A filler (C) containing 75 to 90% by weight of fused silica (c) (75 to 90% by weight of the whole), and a silane compound containing an amino group and the amino groups being all secondary amino groups A process for producing an epoxy resin composition, which comprises melt-kneading a silane coupling agent (D).