JPH0450257A - Epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition having excellent soldering heat-resistance, flame-retardancy and high-temperature reliability and useful for the sealing of semiconductor by compounding a specific epoxy resin, a curing agent, fused silica, a hydrotalcite compound, etc. CONSTITUTION:The objective composition is produced by compounding (A) 4-20wt.% of an epoxy resin having a skeleton expressed by formula (R<1> to R<8> are H, 1-4C lower alkyl or halogen), (B) 2-15wt.% of a curing agent (e.g. phenolic novolak resin), (C) 75-90wt.% of fused silica composed of 99-50wt.% of crushed fused silica having an average particle diameter of <=10mum and 1-50wt.% of spherical fused silica having an average particle diameter of <=40mum, (D) 0.01-10wt.% of a hydrotalcite compound, (E) 0.1-5wt.% of a bromine compound (e.g. brominated epoxy resin) and (F) 0.1-10wt.% of an antimony compound (e.g. antimony trioxide).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an epoxy composition for semiconductor encapsulation that has excellent solder heat resistance, flame retardance, and high temperature reliability.

<Conventional technology> Epoxy resins have excellent heat resistance, moisture resistance, electrical properties, and adhesive properties, and can be given various properties depending on the formulation, so they are used as industrial materials such as paints, adhesives, and electrical insulation materials. has been done.

For example, as methods for sealing electronic circuit components such as the semiconductor device 1, hermetic seals using metals or ceramics, and resin sealing using phenol resins, silicone resins, epoxy resins, or the like have been proposed. However, from the viewpoint of economy, productivity, and balance of physical properties, resin sealing using epoxy resin has become the main method.

On the other hand, recently, the mounting density and automation of components on printed circuit boards has been increasing, and instead of the conventional "insertion mounting method" in which lead bins are inserted into holes in the board, components are soldered onto the surface of the board. ``Surface mounting method'' has become popular.As a result, packages have changed from conventional DIR (dual in-line package) to thin PPP (flat plastic package) suitable for high-density mounting and surface mounting.
packaging).

With the shift to surface mount methods, the soldering process, which used to be a non-issue, has become a major issue. In the conventional pin insertion mounting method, the soldering process only partially heats the leads, but in the surface mount method, the entire package is immersed in a heating medium and heated. Methods used include immersion in a solder bath, heating with saturated steam of inert gas (paper phase method), and infrared reflow method, but in any of these methods the entire package is heated to a high temperature of 210 to 270 degrees Celsius. . Therefore, packages sealed with conventional sealing resin,
When soldering, cracks sometimes occur in the resin part, reducing reliability and making the product unusable.

It is said that the occurrence of cracks during the soldering process is due to moisture absorbed between the post-hardening and the mounting process, which explosively turns into water vapor and expands when soldering is heated. A method is used in which the cured package is completely dried, stored in a sealed container, and shipped.

Various improvements to the sealing resin are also being considered. For example, a method of adding an epoxy resin having a biphenyl skeleton and a rubber component (Japanese Unexamined Patent Publication No. 63-251419), a method of adding an epoxy resin having a biphenyl skeleton and fine powder particles with a particle size of 14 μl or less (Japanese Unexamined Patent Application Publication No. 1983-1999), 87616).

Furthermore, in order to improve the moisture resistance of the sealing resin, the addition of a hydrotalcite compound (Japanese Patent Application Laid-open No. 19625/1983) has been proposed.

On the other hand, electronic components such as semiconductors are required to achieve flame retardancy according to UL standards, and for this reason, flame retardants such as bromine compounds and antimony compounds are usually added to sealing resins.

<Problems to be Solved by the Invention> However, the method of enclosing a dry package in a container has the disadvantage that the manufacturing process and handling of the product are complicated, and the product price is high.

In addition, resins improved by various methods are gradually becoming more effective, but they are not yet fully effective. ) and the method of adding fine powder particles with a particle size of 14u* or less to an epoxy resin having a biphenyl skeleton (Japanese Patent Application Laid-Open No. 1-87616) is effective in preventing cracks in the resin part during soldering, but it is effective at high temperatures. There was a problem with the reliability of the system decreasing.

High-temperature reliability guarantees the functionality of semiconductors in high-temperature environments of 150 to 200°C, and is essential performance for semiconductors that generate a large amount of heat and semiconductors used around automobile engines.

It is known that the problem of high temperature reliability of epoxy resins having a biphenyl skeleton is mainly caused by flame retardants such as bromine compounds and antimony compounds added to impart flame retardancy.

For this reason, an epoxy resin for semiconductor encapsulation that is excellent in all of solder heat resistance, flame retardance, and high-temperature reliability has not been obtained.

The purpose of the present invention is to solve the problem of cracks that occur during the soldering process, and to avoid deterioration in reliability at high temperatures due to the addition of flame retardants. An object of the present invention is to provide an epoxy composition for sealing.

Means for Solving the Problems> The present inventors have achieved the above problems by adding a hydrotalcite compound to an epoxy resin having a biphenyl skeleton, and have created an epoxy composition for semiconductor encapsulation that meets the purpose. The inventors have discovered that a product can be obtained, and have arrived at the present invention.

That is, the present invention provides an epoxy resin (A), a curing agent (8)
, fused silica (C), hydrotalcite compound (D
), a bromine compound (E) and an antimony compound (F), wherein the epoxy resin (A) has the following formula 〇Rj R5R8R2 R3R6R7R4 (wherein R1-R8 are hydrogen atoms, lower Indicates an alkyl group or a halogen atom. Contains as an essential component an epoxy resin (a) having a skeleton represented by
The proportion of the fused silica (C) is 75 to 90% by weight of the whole
The present invention provides an epoxy composition for encapsulating a semiconductor in which the proportion of a hydrotalcite compound (D) is 0.01 to 10% by weight.

Hereinafter, the configuration of the present invention will be explained in detail.

The epoxy resin (A) in the present invention is an epoxy resin (a ) is important to contain as an essential component.

If the epoxy resin (a) is not contained, the effect of preventing cracks in the soldering process will not be exhibited.

In the following formula 〇, preferred specific examples of R1-R8 include a hydrogen atom, a methyl group, an ethyl group, a propyl group, an i-
propyl group, n-butyl group, 5ec-butyl group, ter
Examples include t-butyl group, chlorine atom, and bromine atom.

Preferred specific examples of the epoxy resin (a) in the present invention include 4,4'-bis(2,3-epoxypropoxy)biphenyl, 4,4'-bis(2°3-epoxypropoxy)-3,3 ', 5.5'tetramethylbiphenyl, 4.4'-bis(2,3 eboxyproboxy) -3
,3', 5.5'-tetramethyl-2-chlorobiphenyl, 4.4'bis(2,3-epoxypropoxy)-3,3'5.5'-tetramethyl-2-bromobiphenyl, 4.4'-bis(2,3-epoxy-10boxy)-3,3',5,5'-tetraethylbiphenyl,4
゜4'-bis(2,3-epoxypropoxy)-3゜3
',-5,5'-tetrabutylbiphenyl and the like.

The epoxy resin (A) in the present invention may contain, together with the above-mentioned epoxy resin (a), another epoxy resin other than the epoxy resin (a). Other epoxy resins that can be used in combination include, for example, cresol novolak epoxy resins, phenol novolak epoxy resins, various novolac epoxy resins synthesized from bisphenol A and resorcinol, bisphenol A epoxy resins, and linear aliphatic epoxy resins. , alicyclic epoxy resin, heterocyclic epoxy resin, halogenated epoxy resin, and the like.

Epoxy resin (a>
There is no particular restriction on the ratio of (A) usually needs to contain 50% by weight or more, preferably 70% by weight or more.

In the present invention, the blending amount of the epoxy resin (A) is usually 4
-20% by weight, preferably 6-18% by weight.

The curing agent (B) in the present invention is not particularly limited as long as it can be cured by reacting with the epoxy resin (^), and specific examples thereof include phenol novolac resin, cresol novolak resin, bisphenol A, etc. Various novolak resins synthesized from resorcinol, various polyhydric phenol compounds, maleic anhydride, phthalic anhydride,
Examples include acid anhydrides such as pyromellitic anhydride, and aromatic amines such as metaphenylene diamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

For semiconductor device encapsulation, phenolic curing agents are preferably used in terms of heat resistance, moisture resistance, and storage stability.
Depending on the application, two or more types of curing agents may be used together.

In the present invention, the blending amount of the curing agent (B) is usually 2 to 15
% by weight, preferably 3-10% by weight. Furthermore,
From the viewpoint of mechanical properties and moisture resistance, the compounding ratio of the epoxy resin (A) and the curing agent (B) is such that the chemical equivalent ratio of (B) to (^) is 0.7 to 1.3, particularly 0.8. It is preferably in the range of 1.2 to 1.2.

In addition, in the present invention, epoxy resin (A) and curing agent (B
) may be used as a slick curing catalyst to promote the curing reaction of
The curing catalyst is not particularly limited as long as it promotes the curing reaction, and examples thereof include 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2phenylimidazole, 2-phenyl-4- Imidazole compounds such as methylimidazole and 2-heptadecylimidazole, triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, 2-
(dimethylaminomethyl)phenol, 2,4.6-tris(dimethylaminomethyl)phenol, tertiary amine compounds such as 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, trimethylphosphine, triethylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, tri(nonylphenyl) ) Organic phosphine compounds such as phosphine can be mentioned. Among them, organic phosphine compounds are preferred from the viewpoint of moisture resistance, and triphenylphosphine is particularly preferably used.

Depending on the application, these curing catalysts may be 2N! The above may be used in combination, and the amount added is preferably in the range of 0.5 to 5 parts by weight per 100 parts by weight of the epoxy resin (A).

Fused silica (C) in the present invention means non-quality silica having a true specific gravity of 2.3 or less. Its production does not necessarily have to go through a molten state, and any production method can be used. Examples include a method of melting crystalline silica and a method of synthesizing it from various raw materials.

The shape and particle size of the fused silica (C) are not particularly limited, but it consists of 99-50% by weight of crushed fused silica with an average particle size of 10-4 or less and 1-50% by weight of spherical fused silica with an average particle size of 40-4 or less. Fused silica (C) is preferably used because it has a large effect of improving soldering heat resistance and has good fluidity. Among them, 99 to 50% by weight, especially 99 to 70% by weight of crushed fused silica with an average particle size of 10- or less, especially 34 to 10N, and spherical fused silica with an average particle size of 4IJ11 or less, especially Ol uwr or more and 4- or less. Silica 1-50% by weight, especially 1-3
0% by weight, and the average particle size of the spherical fused silica is smaller than the average particle size of the crushed fused silica, especially when the former is 1/1/2 of the latter.
Fused silica (C) of 2 or less is most preferably used.

Here, the average particle size means the particle size (median diameter) that accounts for 50% of the cumulative weight, and when two or more types of crushed silica with different average particle sizes or spherical fused silica are used together, the mixture is crushed. Or mean the average particle size of spherical fused silica.

In the present invention, the proportion of fused silica (C) is 75% of the total
90% by weight, more preferably 75 to 88% by weight. If the amount of fused silica (C) is less than 75% by weight of the total, the soldering heat resistance will be insufficient, and if it exceeds 90% by weight, the fluidity will be insufficient.

The hydrotalsate compound fD) in the present invention is a composite metal compound represented by the following formula (1) or (2).

M g z Aj! F (OH) 2x+3y-,z
A z ・mW 20 ・=...0MgeA1A0
, 2 engineering + 31 + / □ 10110. @(
Where, A is a functional group capable of generating an n-valent anion A1-, n is an integer of 1 to 3, and x, y, and Z are O< y /
In the above formula Preferred examples of the anion A″- include F, CI/,
,Br,■,0)I,HCO3,CH3COO
, HCOO, CO32-5SO42-(COO)2, tartrate ion (CH(OH)Coo)2, citrate ion (:C(OH)Coo)(CH2COO)2
, salicylate ion C6H4(OH)Co.

- etc. Among them, CO32- is particularly preferred.

Hydrotalcite compound (D) represented by the above formula (■)
For example, it is produced by firing the hydrotalcite compound (D) represented by the above formula (1) at 400 to 900°C.

As a preferable specific example of the hydrotalcite compound (0), MgcsA12 (OH)+3CO3・3.5
H20, Mgc, A12 (OH)t3cO3, Mg
s A 1 ts (OH) +3 CO3・3.5
H20, Mg5Aj! ti(OH)13CO3, Mg
aAj! 2(OH)16CO3・4H20, MgaA
j! 2(OH)16CO3, Mgo, 5bAflo3s
Or, +7s, M g 0.7A fl o, io 1
．． l S, Mgo, tsAl. 2501. +25,M
go, sA 1°201.1, etc.

In the present invention, the amount of hydrotalcite compound (D) added is 0.01 to 10% by weight, preferably 0.0% by weight of the total.
2 to 5% by weight, particularly preferably 0.05 to 2% by weight. If the amount added is less than 0.01% by weight, the effect of improving high temperature reliability will be insufficient, and if it exceeds 10% by weight, the soldering heat resistance will decrease.

The bromine compound fE) and antimony compound (F) in the present invention are usually added to the epoxy composition for semiconductor encapsulation as a flame retardant, and are not particularly limited, and known compounds can be used.

Preferred specific examples of the bromine compound (E) include brominated epoxy resins such as brominated bisphenol A epoxy resins and brominated phenol novolak epoxy resins, brominated polycarbonate resins, brominated polystyrene resins, brominated polyphenylene oxide resins, Examples include tetrabromobisphenol A, decabromodiphenyl ether, etc. Among them, brominated epoxy resins such as brominated bisphenol A type epoxy resin and brominated phenol novolac type epoxy resin are particularly preferably used.

The amount of the bromine compound (E) added is preferably 0.1 to 5% by weight of the total in terms of bromine atoms, particularly preferably 0.2 to 2% by weight in terms of flame retardancy and high temperature reliability. .

Further, a preferable specific example of the antimony compound (F) is antimony trioxide.

The amount of antimony compound (F) added is 0.1 to 1 of the total amount.
0% by weight is preferred in terms of flame retardancy and high temperature reliability, particularly preferably 02 to 4% by weight.

In addition to fused silica (C), the epoxy composition for semiconductor encapsulation of the present invention includes crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay,
Talc, calcium silicate, titanium oxide, antimony oxide, asbestos, glass fiber, etc. can be added.

In the present invention, it is preferable to surface-treat the filler such as molten perilla (C) with a coupling agent such as a silane coupling agent or a titanate coupling agent in advance from the viewpoint of reliability.Epoxy silane is used as the coupling agent. Silane coupling agents such as , aminosilane, and mercaptosilane are preferably used.

The epoxy composition for semiconductor encapsulation of the present invention includes colorants such as carbon black and iron oxide, elastomers such as silicone rubber, modified nitrile rubber, and modified polybutadiene rubber, and thermoplastic resins such as polyethylene. , a long chain fatty acid, a metal salt of a long chain fatty acid, an ester of a long chain fatty acid, an amide of a long chain fatty acid, a mold release agent such as paraffin wax, and a crosslinking agent such as an organic peroxide can be optionally added.

The epoxy composition for semiconductor encapsulation of the present invention is preferably melt-kneaded, for example in a Banbury mixer or kneader.
It is produced by melt-kneading using a known kneading method such as a roll, single-screw or twin-screw extruder, or co-kneader.

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

Examples 1 to 9, Comparative Examples 1 to 7 The fused silica (C) shown in Table 1 and the hydrotalcite compound (0) shown in Table 2 were mixed in a reagent mixer at the composition ratio shown in Table 2. It was triblended. This was melt-kneaded using a twin-screw extruder with a barrel set temperature of 90° C., then cooled and pulverized to produce an epoxy composition for semiconductor encapsulation.

Using this composition, 1
The compositions were molded at 75° C. for 2 minutes, post-cured at 175° C. for 8 hours, and the physical properties and moldability of each composition were measured using the following physical property measuring method.

A1 is deposited on the solder heat resistant two surfaces and fS'#1. Twenty 28-pin 5OPs equipped with pseudo-elements were molded and post-cured, and after humidifying at 85°C/85%RH for 50 hours, they were immersed in a solder bath heated to 260°C for 10 seconds, and sops with cracks were rejected.

Flame retardancy: A 5'' x 1/2''XI/16'' flame test piece was molded and post-cured, and its flame retardance was evaluated according to the UL94 standard.

28pin5op after high temperature reliability and soldering heat resistance evaluation
Evaluate the high temperature reliability at 200℃ using

As shown in Table 3, the epoxy compositions for semiconductor encapsulation of the present invention (Examples 1 to 9) are excellent in solder heat resistance, flame retardancy, and high temperature reliability.

On the other hand, Comparative Example 1 which does not contain epoxy resin (a)
In Comparative Examples 2 to 4, which do not contain the bromine compound (E) and/or the antimony compound ([), the flame retardance is poor.

Furthermore, Comparative Example 5, which does not contain the hydrotalcite compound CD), has poor high temperature reliability.

Furthermore, in Comparative Examples 6 and 7, in which the content of fused silica (0) was outside the range of the present invention, the soldering heat resistance was poor, or the composition was not obtained due to the load upon cross-wiring.

<Effects of the Invention> The epoxy composition for semiconductor encapsulation of the present invention contains a specific epoxy resin, a curing agent, fused silica, a hydrotalcite compound, a bromine compound, and an antimony compound, so it has excellent soldering heat resistance and flame retardancy. Excellent performance and high temperature reliability.

Claims (2)

[Claims] (1) A resin composition comprising an epoxy resin (A), a curing agent (B), fused silica (C), a hydrotalcite compound (D), a bromine compound (E), and an antimony compound (F), The epoxy resin (A) has the following formula (I
) ▲There are mathematical formulas, chemical formulas, tables, etc.▼…(I) (However, R^1 to R^8 are hydrogen atoms, C_1 to C_4
represents a lower alkyl group or a halogen atom. ) Contains an epoxy resin (a) having a skeleton represented by
5 to 90% by weight, and contains hydrotalcite compounds (
An epoxy composition for semiconductor encapsulation, in which the proportion of D) is 0.01 to 10% by weight. (2) The semiconductor encapsulation according to claim 1, wherein the fused silica (C) consists of 99 to 50% by weight of crushed fused silica with an average particle size of 10 μm or less and 1 to 50% by weight of spherical fused silica with an average particle size of 40 μm or less. Epoxy composition for stopping.