JPH02147619A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To improve moldability, printability, moisture resistance, thermal shock resistance, etc., by compounding a random-copolymerized silicone-modified epoxy resin, a specified curing agent, a silicone copolymer, a silicon rubber and a filler. CONSTITUTION:A random-copolymerized silicone-modified epoxy resin (A) is obtd. by reacting an epoxy resin (a) of an epoxy equivalent of 150-250 and a softening point of 60-130 deg.C, contg. a small amt. of ionic impurities and having two or more epoxy groups in the molecule with an organopolysiloxane (b) having a functional group reactive with the component (a). Separately, a random-copolymerized silicone-modified phenolic resin curing agent (B) is obtd. by reacting a phenol novolak resin (c) of an OH equivalent of 80-150 and a softening point of 60-120 deg.C and contg. a small amt. of ionic impurities with an organopolysiloxane (d) having a functional group reactive with the component (c). A mixture of the components A and B, 0.1-2wt.% silicone copolymer (C) of an SP value of 7-9 based on the mixture, 1-20wt.% silicone rubber (D) of an SP value of 7-9 based on the mixture and an inorg. filler (E) are compounded together.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention provides improvements in molding processability (mold stains, resin spots, molding voids,
The present invention relates to an epoxy resin composition for semiconductor encapsulation that has excellent mold releasability), imprintability, moisture resistance, thermal shock resistance, and soldering heat resistance.

(Prior art) In recent years, epoxy resin compositions have been used in large quantities and most commonly for resin encapsulation of semiconductor elements such as IC%LSI, l-lan sisters, diodes, and electronic circuits due to their characteristics, cost, etc. It is being

However, as electronic components become more mass-producible, become lighter, thinner, shorter, and more compact, and the degree of integration increases, requirements for sealing resins are becoming stricter. In particular, there is a strong demand for epoxy resin compositions that have a good balance between improved molding processability and imprintability, as well as moisture resistance, thermal shock resistance, and soldering heat resistance.

However, it is moisture resistant and heat resistant! ! ◇ Even in ordinary epoxy resin compositions that do not contain F-5 additives, mold stains, resin flakes, etc. may occur due to the influence of additives such as mold release agents.
Although there is a tendency for voids to occur and poor marking properties to occur,
Silicone oil, to improve moisture resistance and thermal shock resistance.
Additives such as silicone compounds such as silicone rubber, synthetic rubber, and thermoplastic resins must be used, and the use of these additives further worsens mold stains, resin flakes, molding voids, and poor marking properties. There is a tendency to

Mold stains and poor marking properties occur because these additive components stand out on the surface of the molded product during the molding process, and resin particles and molding voids increase because these components interact with epoxy resin, etc. This is due to poor solubility.

In order to improve these problems, various additives have been studied, and one that is effective in molding processability, marking properties, etc. is epoxy resin J-G. It has been proposed to add a silicone oil made of a copolymer of alkylene oxide (JP-A No. 60-13841, Japanese Patent Publication No. 60-13841,
2-61.215), although these are effective in improving molding processability and stamping properties, they are not effective in heat resistance @ impact resistance and soldering heat resistance, and furthermore, moisture resistance is slightly reduced. It was expected to decrease.

Additionally, addition polymers of epoxy resins containing alkenyl groups and organopolysiloxanes are added to epoxy resin systems to improve heat resistance (high Tg), heat resistance @ impact resistance, and soldering heat resistance (crack resistance). compositions have been proposed (JP-A-62-84147, JP-A-62-21).
2417, etc.), but these are all heat resistant (high T
g) The main purpose is to improve thermal shock resistance and soldering heat resistance (crack resistance), and these addition polymers contain a large amount of unreacted and incompatible organopolysiloxane. However, it was only a product that was incompatible with moldability and stampability.

In addition to this, a block polymer consisting of an aromatic polymer and an organopolysiloxane has been proposed as an additive (Japanese Unexamined Patent Publication No. 58-21417), but it has poor moldability and
Although the imprintability and thermal shock resistance are improved, since it is a block copolymer, the concentration of the silicone part is uneven, and the compatibility with other components is poor, making it unsatisfactory. Almost no effect was observed.

Furthermore, there is a composition containing at least one of the phenol resins modified with organopolysiloxane as an essential component, as well as the phenol novolac type epoxy resin modified with organopolysiloxane, and the phenol novolac type epoxy resin and the 7-enol resin as optional components. The proposed method (Japanese Patent Application Laid-Open No. 136860/1986) is also aimed at improving the moisture resistance after immersion in solder, and the aim is to make the entire resin composition hydrophobic. However, there is a sacrifice in terms of gender, and the balance that is the object of the present invention is lacking.

(Objective of the Invention) The object of the present invention is to provide a material with good molding processability (mold contamination, resin breakage, mold void mold releasability), stamping property, moisture resistance, thermal shock resistance, and soldering heat resistance. An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation.

(Structure of the Invention) The present inventors conducted intensive studies to obtain a well-balanced and excellent epoxy resin composition for semiconductor encapsulation, which could not be overcome using conventional techniques. Combining a silicone-based copolymer that is compatible with both the random copolymerized silicone-modified epoxy resin obtained by the above process and the random copolymerized silicone-modified phenol novolak resin as a curing agent and has a specific solubility parameter (hereinafter referred to as SP value). This further improves molding processability and imprintability compared to conventional products, and in addition, by improving the adhesion between the lead frame and IC chip and the encapsulating resin, a product with excellent solder heat resistance can be obtained. It will be done.

Furthermore, by combining silicone rubber, liquid synthetic rubber, or a mixture of silicone rubber and liquid synthetic rubber, which are highly compatible with the silicone copolymer, moldability, stampability, soldering heat resistance, and impact resistance are significantly improved. It was discovered that a very well-balanced composition could be obtained, leading to the completion of the present invention.

The organopolysiloxane used in the present invention as a raw material for the random copolymerized silicone-modified epoxy resin obtained by reacting the organopolysiloxane as component (A) with an epoxy resin has a functional group that can react with the epoxy resin. Examples of these functional groups include alkoxy groups, hydroxyl groups, amine groups, and hydrosilyl groups, and the molecular structure of the organopolysiloxane may be either linear or branched.

The epoxy resin to be reacted with these surganopolysiloxanes may be any resin as long as it has two or more epoxy groups in one molecule, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type. Examples include epoxy resins, cresol novolac type epoxy resins, alicyclic epoxy resins, and modified resins thereof, and these epoxy resins may be used alone or in combination of two or more.

Among these epoxy resins, the epoxy equivalent is 150~
250, a softening point of 60 to 130°C, and Na”
, CI-, etc. are preferably contained as little as possible.

The reaction method of the random copolymerized silicone-modified epoxy resin using these raw materials is not particularly limited, but for example, an organopolysiloxane having two or more amino groups is reacted with some epoxy groups of the epoxy resin. There are methods to obtain a random copolymer by reacting an alkenyl group-containing epoxy resin with an organopolysiloxane having two or more hydrosilyl groups.

The random copolymerized silicone-modified epoxy resin of the present invention is a product in which organopolysiloxanes are randomly copolymerized, and the silicone domains are uniformly dispersed compared to those obtained by simple block copolymerization, resulting in improved moldability, printing properties, and
It has excellent moisture resistance and thermal shock resistance.

In addition, in the present invention, the random copolymerized silicone-modified epoxy resin may be used alone or mixed with conventional epoxy resins, but in these mixed systems, the random copolymerized silicone-modified epoxy resin should account for 50% or more. It is necessary.

The random copolymerized silicone-modified phenol novolac resin used as component (B) in the present invention functions as a curing agent.

The organopolysiloxane used as a raw material for these random copolymerized silicone-modified phenol novolak resins has a functional group that can react with the phenol novolak resin, and these functional groups include, for example, epoxy groups, alkoxy groups, and hydrosilyl groups. The molecular structure of the organopolysiloxane may be either linear or branched.

Examples of the phenol novolak resins to be reacted with these organopolysiloxanes include phenol novolacs, talesol novolaks, and modified resins thereof.
These can also be used in L types or in a mixture of two or more types.

The phenol novolac resin used has a hydroxyl equivalent of 8
0 to 150, the softening point is 60 to 120°C, and Na"
, CI-, and other ionic impurities are preferably as few as possible.

The random copolymerized silicone-modified phenol novolak resin of the present invention is obtained by reacting an organopolysiloxane having a reactive functional group with a phenol novolak resin in the presence of a catalyst such as a tertiary amine or an organic phosphine compound. The random copolymerized silicone-modified phenol novolak resin of the invention is a product in which organopolysiloxane is randomly copolymerized, and compared to a simple block copolymerization product, the silicone domains are uniformly dispersed, so it has improved moldability, printing properties, and Excellent moisture resistance and thermal shock resistance.

In addition, in the present invention, the random copolymerized silicone-modified phenol resin curing agent may be used alone or in combination with other 7L nornovolac type curing agents, but in these mixed systems, the random copolymerized silicone-modified phenol It is desirable to use resin in an amount of 50% by weight or more in the curing agent system.

The SP value of component (C) used in the present invention is 7 to 9.
The silicone copolymer is effective in improving the compatibility between epoxy resin and random copolymerized silicone-modified phenol resin, and is effective in improving molding processability, marking properties, and lead frames and I
It also has the effect of improving soldering heat resistance by improving the adhesion between the C chip and the sealing resin.

When the SP value of the silicone copolymer is less than 7, it becomes too hydrophobic and the compatibility with epoxy resin and random copolymerized silicone-modified phenol resin decreases, and when it exceeds 9, it becomes too hydrophilic and the epoxy resin The SP value of the silicone copolymer is 7 because the compatibility with the random copolymerized silicone-modified phenol resin decreases.
It is necessary that it be within the range of ~9.

Regarding silicone copolymers, there is no particular restriction on the structure as long as the SP value is within the range of 7 to 9. It's okay to have one.

A copolymer of organopolysiloxane and alkylene oxide having a structure such as, or R0 to R4;
-CH,, -C,H,, -CH=CH,, (However, R
3-R4 may be the same group or may be different groups.

Examples include a copolymer of organopolysiloxane with heptastyrene having the structure shown below.

These silicone copolymers have a resin content (A-1-B)
It is used within the range of 0.1-12% by weight.

If the amount added is less than 0.1% by weight, the effect of improving soldering heat resistance will be insufficient, and if it exceeds 12% by weight, moldability will be reduced.

Furthermore, the SP value used as component (D) of the present invention is 7 to
Silicone rubber, liquid synthetic rubber, or a mixture of silicone rubber and liquid synthetic rubber in the range of 9 is a low stress agent that is highly compatible with the silicone copolymer used as component (C), and is a low stress agent that is compatible with the silicone copolymer used as component (C). When used in combination with a random copolymerized silicone-modified epoxy resin, a random copolymerized silicone-modified phenol resin as the component (B), and a silicone copolymer as the component (C), moldability, stampability, soldering heat resistance, and thermal shock resistance can be improved. Both sexes are significantly improved.

The reason for this is that the random copolymerized silicone-modified epoxy resin (A) is improved by the silicone-based copolymer (C).
The compatibility between the random copolymerized silicone-modified phenolic resin of component (B) is further improved by combining silicone rubber, liquid synthetic rubber, or a mixture (D) of silicone rubber and liquid synthetic rubber; This is because marking properties and soldering heat resistance are significantly improved.

Furthermore, a random copolymerized silicone-modified epoxy resin (A) and a random copolymerized silicone-modified phenol resin (B), which have low stress effects, are combined with silicone rubber, liquid synthetic rubber, or a mixture of silicone rubber and liquid synthetic rubber (D). It is thought that this significantly improves thermal shock resistance.

Among the silicone rubbers used as component (D) of the present invention, the silicone rubber is three-dimensionally crosslinked and so-called cured, and there are no particular limitations as long as its SP value is in the range of 7 to 9. The average particle size of silicone rubber is 30μ
m or less, preferably spherical (with an aspect ratio of 1.5 or less), and has reactivity or affinity with random copolymerized silicone-modified epoxy resin and/or random copolymerized silicone-modified phenol resin. Silicone rubber is preferred, and spherical rubber with an average particle size of 15 μm or less is more preferred. Examples of these silicone rubbers include spherical silicone rubbers obtained by interfacial polymerization of organopolysiloxanes containing vinyl groups and organopolysiloxanes containing hydrogen groups.

These silicone rubbers have a ratio of 1 to the resin content (A + B).
It is used within the range of 20% by weight.

If the amount of these additives is less than 1% by weight, the effect of improving moldability, stampability, thermal shock resistance, and soldering heat resistance will be insufficient, and if it exceeds 20% by weight, the hardness at the time of molding and the molded product will be insufficient. strength will decrease.

The liquid synthetic rubber is preferably a diene-based rubbery polymer having one or more epoxy groups capable of reacting with a curing agent in its molecule, such as epoxidized polybutadiene rubber.

These liquid synthetic rubbers have a ratio of 0.0% to the resin content (A+B).
It is used in a range of 5 to 15% by weight.

If the amount of these additions is less than 0.5% by weight, moldability is improved.
The effects of improving stampability, thermal shock resistance, and soldering heat resistance will be insufficient, and if it exceeds 15% by weight, the hot hardness during molding and the strength of the molded product will decrease.

Further, as a mixture of silicone rubber and liquid synthetic rubber, it is preferable that the liquid synthetic rubber is mixed in a range of 20 to 100 parts per 100 parts of silicone rubber.

A mixture of these silicone rubbers and liquid rubber is used in an amount of 05 to 13% by weight based on the resin content (A+B).

If the amount of these additions is less than 0.5% by weight, moldability is improved.
The effects of improving stampability, thermal shock resistance, and soldering heat resistance will be insufficient, and if it exceeds 13% by weight, the hot hardness during molding and the strength of the molded product will decrease.

Examples of the inorganic filler as component (E) used in the present invention include crystalline silica, fused silica, alumina, calcium carbonate, talc, mica, glass fiber, etc. These may be used singly or in combination of two or more. Ru.

Among these, crystalline silica or fused silica is particularly preferably used.

In the present invention, random copolymerized silicone-modified epoxy resin (A), random copolymerized silicone-modified phenol resin (B), silicone copolymer (C), silicone rubber and/or synthetic rubber (D), and inorganic filler (
In addition to E), if necessary, tertiary amines such as BDMA,
imidazoles, 1,8-diazabicyclo(5,4,0
) Hardening accelerators such as organic phosphorus compounds such as undecene-7 and triphenylphosphine, mold release agents such as natural waxes and synthetic waxes, flame retardants such as hexabromobenzene, decabromo biphenyl ether, and antimony trioxide, and carbon. Coloring agents such as black and red iron oxide, silane coupling agents, geothermal plastic resins, etc. can be appropriately added and blended.

A general method for manufacturing the epoxy resin composition for semiconductor encapsulation of the present invention is to mix raw materials with a predetermined composition ratio sufficiently uniformly using a mixer, etc., and then melt-mix them using a roll, kneader, etc. This can be easily carried out by cooling, solidifying, and pulverizing into an appropriate size.

(Example) Example 1 Random copolymerized silicone-modified epoxy resin (a)*'
90 parts by weight Brominated phenol novolac epoxy resin (epoxy equivalent: 370, softening point: 65°C, bromine content: 37 wt%) 10 Random copolymerized silicone-modified phenol resin (c) pieces = 50
7/Copolymer water of organopolysiloxane and alkylene oxide @ 6 Silicone rubber 7 tt fused silica
470 ll antimony trioxide
25 l/silane coupling agent
2 〃1.8-diazabicyclo(5,4,
0) Undecene-7tt Carnauba Wax 311 Carbon Black 3// are sufficiently mixed at room temperature, further kneaded at 95 to 100°C, cooled, and then crushed to form tablets to obtain the epoxy resin composition for semiconductor encapsulation of the present invention. I got something.

The mold staining property and resin parity of this material were determined using a transfer molding machine (molding conditions: mold temperature: 175°C, curing time: 2 minutes), and the molded product obtained was evaluated at 175°C.
The package was post-cured for several hours, and voids inside the package, stampability, thermal shock resistance, moisture resistance, and soldering heat resistance were evaluated.

The results are shown in Table 2.

Example 2 In Example 1, the random copolymerized silicone-modified epoxy resin (a) was replaced with two random copolymerized silicone-modified epoxy resins (b), and the random copolymerized silicone-modified phenol resin (c) was replaced with the random copolymerized silicone-modified phenol resin (c). D) *1. Example 1 except that the copolymer of organopolysiloxane and alkylene oxide was changed to copolymer water 7 of styrene and organopolysiloxane, and 7 parts by weight of silicone rubber was changed to 20 parts by weight. An epoxy resin composition for semiconductor encapsulation was obtained in the same manner as above.

The mold staining property and resin release of this material were determined using a transfer molding machine (molding conditions: mold temperature 175°C, curing time 2 minutes), and the resulting molded product was post-cured at 175°C for 18 hours and packaged. Internal voids, imprintability, thermal shock resistance, moisture resistance, and soldering heat resistance were evaluated.

The results are shown in Table 2.

Examples 3 to 9 Epoxy resin compositions for semiconductor encapsulation having the compositions shown in Table 1 were obtained in the same manner.

The evaluation results of this epoxy resin composition for semiconductor encapsulation were evaluated in the second
Shown in the table.

Comparative Example 1-12 In the same manner, an epoxy resin composition for semiconductor encapsulation having the composition shown in Table 1 was obtained.

The evaluation results of this epoxy resin composition for semiconductor encapsulation were evaluated in the second
Shown in the table.

(Hereinafter referred to as Ronihyakun*1 A random copolymerization of an epoxy resin represented by formula (I) and orthoallylphenol and an organopolysiloxane represented by formula (II) to form an epoxy resin/organopolysiloxane. Random copolymerized silicone-modified epoxy resin reacted at 100/20 (weight ratio) (epoxy equivalent: 250, softening point: 78 °C) Copolymerization of resin and bisphenol A. Random copolymerization of epoxy resin and organopolysiloxane represented by formula (IV). Epoxy resin/organopolysiloxane 100/20 (weight ratio).
Random copolymerized silicone-modified epoxy resin (epoxy equivalent: 260, softening point: 75°C) (i1/m/r+10m20,05) A random copolymerized novolak and an organopolysiloxane represented by formula (Vl) are combined to form a random copolymerized novolac/organopolysiloxane I OO/20 (
Random copolymerized silicone-modified phenol resin (OH equivalent: 125, softening point: 95°C) reacted at 4 phenol novolak resin (OH equivalent: 125, softening point: 95°C) 1 m/n+m = 0.08 ) and the organopolysiloxane represented by the formula [■], a random copolymerized silicone-modified phenol resin (OH per ff11
27, softening point 97°C) This 5 phenol novolac resin (OH ff1106, softening point 100°C) and both terminal epoxy-modified dimethylsiloxane represented by the formula [■],
Phenol novolak resin/dimethylsiloxane 10
Random copolymerized silicone-modified phenol resin (OH equivalent 157, softening point 96°C) reacted at 0/33.3 (weight ratio) *6 Copolymer represented by formula (II) *7 With formula (X) The copolymer rubber shown (average particle size I5μ, spherical, SP value 7.5) is a liquid epoxidized polybutadiene rubber (oxygen-containing ff17) in which a part of the unsaturated double bonds of zero I0 butadiene rubber is oxidized and epoxidized. %, viscosity 5500 poise, SP value 8.4) (y Neriko Mujiro) *Polydimethylsiloxane represented by formula 6 (XI)”
Type 011 spherical solid silicone obtained by three-dimensional crosslinking through interfacial polymerization of vinyl group-containing organopolysiloxane and hydrogen-containing orcappolysiloxane. Judgment is based on the number of molding shots until fogging occurs.

*12 Measure the length of the resin pad at the vent part of the molded product obtained.

*Use a molded product with llQ shots and peel off the sellotape after stamping! At 2 o'clock, the judgment is based on the number of seals taken.

The table shows the number of peeled stamps out of 50 molded products.

*1' 0 molded pieces (post-curing 175°C, 8Hrs) were subjected to a temperature cycle test (150°C to -65°C),
Judging by the number of cracks that occur after 500 cycles of testing. The table shows the number of cracks in 20 molded products.

100 pieces of 15 molded products (post-curing 175°0.8Hrs)
A 1,000-hour moisture resistance test was conducted in high-pressure steam at 120°C, and the number of defective pieces was determined. The table shows 100 molded products.
Indicates the number of defective items among the items.

After treating 16 pieces of Zero 16 molded products (post-curing at 175°C, 8Hrs) in 85°C and 185% steam for 72 hours, 260
It was immersed in a solder bath at ℃ for 10 seconds and judged by the number of pieces that generated silk. The table shows the number of cracks among 16 molded products.

(Left below) (Effects of the invention) Molding can be performed by combining a silicone copolymer having a solubility parameter (SP value) that is compatible with both a random copolymerized silicone-modified epoxy resin and a random copolymerized silicone-modified phenol resin. By combining silicone rubber, liquid synthetic rubber, or a mixture of silicone rubber and liquid synthetic rubber, which has good compatibility with silicone-based copolymers, the soldering heat resistance is improved by improving the properties, imprintability, and adhesion. Further improvements in moldability, stampability, and solder heat resistance have been made.
Furthermore, an epoxy resin composition for semiconductor sealing pressure with significantly improved impact resistance is obtained.

This epoxy resin composition for semiconductor encapsulation has excellent impact resistance, making it possible to encapsulate large chips, and has excellent soldering heat resistance, making it highly reliable even when used in thin packages. It is.

Claims (3)

[Claims] (1) (A) Random copolymerized silicone-modified epoxy resin made by reacting organopolysiloxane and epoxy resin (B) Random copolymerized silicone-modified phenol resin curing agent made by reacting organopolysiloxane and phenol novolac resin (C ) Silicone copolymer with an SP value in the range of 7 to 9 (D) Silicone rubber with an SP value in the range of 7 to 9 (E) Inorganic filler is an essential component and is based on the resin component (A + B) An epoxy resin composition containing 0.1 to 12% by weight of a silicone copolymer (C) and 1 to 20% by weight of silicone rubber (D). (2) SP as component (D) in patent claim (1)
Using liquid synthetic rubber with a value in the range of 7 to 9, the resin content (
An epoxy resin composition containing 0.5 to 15% by weight of liquid synthetic rubber (D) based on A+B). (3) SP as component (D) in patent claim (1)
Use a mixture of silicone rubber and liquid synthetic rubber with a value in the range of 7 to 9, and contain 0.5 to 13% by weight of the mixture (D) of silicone rubber and liquid synthetic rubber based on the resin content (A + B). An epoxy resin composition characterized by: