JP2000103838A - Epoxy resin composition for semiconductor sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which is a one-package composition having stability against moisture, a low viscosity, and good storage stability and can give a cured product having high heat resistance, high humidity resistance, and excellent adhesion by mixing an epoxy compound with diethylamine. SOLUTION: The epoxy compound is an epoxy resin used alone or in combination with a reactive diluent or another epoxy compound. The epoxy resin is desirably one having at least two epoxy groups. It is desirable that the reactive diluent or another epoxy compound is used in an amount of at most 30 wt.% based on the epoxy compound. The amount of diethyltoluenediamine used is in the range of 0.7-1.4 equivalents of the active hydrogen atoms of diethyltoluenediamine per equivalent of the epoxy groups of the epoxy compound. It is the most desirable that the cure accelerator used is tris- acetylacetonatocobalt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an epoxy resin composition used as a semiconductor encapsulant. More specifically, a one-pack type epoxy resin composition that is stable against moisture, has low viscosity and good storage stability, has high heat resistance when cured, has high moisture resistance, and has high adhesiveness. The present invention relates to an excellent epoxy resin composition for semiconductor encapsulation.

[0002]

2. Description of the Related Art Liquid epoxy resin compositions are preferred in the field of sealing semiconductors with liquid resin compositions such as tape carrier packages because of their excellent workability. It is used.

However, the epoxy resin composition for semiconductor encapsulation peels off at the interface between the chip and the encapsulating resin during heating due to the stress generated by the difference between the coefficient of thermal expansion of the silicon chip and that of the encapsulating resin. In order to prevent such problems as above, the inorganic filler is generally contained in a high ratio. By containing the inorganic filler, the coefficient of thermal expansion of the resin composition can be made closer to that of the silicon chip. For this reason, the composition before being filled with the inorganic filler must have a low viscosity.

The epoxy resin composition for semiconductor encapsulation is used as a one-pack type resin composition in order to suppress the variation of the compounding ratio and increase the productivity. Sex matters. Generally, -40 to -2
It is a practical level that there is no large increase in viscosity even when stored at a low temperature of 0 ° C. for one year or more, and the rate of increase in viscosity after one day at room temperature is twice or less.

Furthermore, the epoxy resin composition for semiconductor encapsulation must have high levels of heat resistance, moisture resistance and adhesion when cured.

[0006] Conventionally, as a curing agent for an epoxy resin composition for encapsulating a semiconductor, a curing agent having a low viscosity and a relatively good storage stability can be obtained, so that an acid anhydride such as methylhexahydrophthalic anhydride is used. Often used.

However, when an acid anhydride is used as a curing agent, it is easily affected by moisture because of its high hygroscopicity, which is not suitable for producing a stable composition. Further, since an ester bond is generated by a curing reaction, the compound is easily hydrolyzed, and water easily penetrates in a PCT test or the like for evaluating moisture resistance of a cured product. The infiltrated water causes hydrolysis of the ester bond, corrosion of the semiconductor element, cracking of the sealing component due to vaporization of the water during heating, and the like. Further, the adhesiveness to metal is not sufficient.

On the other hand, when a liquid amine compound is used as a curing agent, there is no problem as described above. However, since many liquid amine compounds are of an aliphatic type, heat resistance of a cured product cannot be expected. It has been considered that it is difficult to obtain a one-pack type resin composition having high heat resistance when a cured product is obtained due to low storage stability and the like.

[0009]

In view of the above-mentioned circumstances, the present inventors have developed a one-pack type epoxy resin composition for semiconductor encapsulation which is stable against moisture, has low viscosity and good storage stability. As a result of extensive studies to provide a cured product having high heat resistance, high moisture resistance, and excellent adhesion, it has been used as a curing agent for epoxy resin compositions for semiconductor encapsulation. When the unused diethyltoluenediamine (B) was used as a curing agent, it was found that the above object was achieved, and the present invention was completed.

That is, the present invention provides an epoxy resin composition for semiconductor encapsulation containing (A) an epoxy compound and (B) diethyltoluenediamine (Claim 1), and further comprises (C) a curing accelerator. The epoxy resin composition according to claim 1 (claim 2) and the epoxy resin composition according to claim 2 wherein the component (C) is tris-acetylacetonatocobalt (III).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin composition for semiconductor encapsulation (I) (hereinafter sometimes simply referred to as composition (I)) of the present invention comprises an epoxy compound (A) as a main component and a curing agent. It is a one-part composition containing diethyltoluenediamine (B).

Examples of the epoxy compound include various epoxy resins, reactive diluents, and other epoxy compounds. These may be used alone or as a mixture of two or more. The reactive diluent and other epoxy compounds are components used for adjusting the viscosity of the composition and the elastic modulus of the cured product.

The epoxy resin is preferably one having two or more epoxy groups in the molecule, since it can form a crosslinked structure capable of exhibiting sufficient heat resistance. Further, four or less, and more preferably three or less are preferable in that a low-viscosity resin composition can be obtained. If the number of epoxy groups contained in the molecule is too small, the heat resistance of the cured product will be low, and the tendency of the strength to be weak will tend to occur.If the number is too large, the viscosity of the resin composition will increase,
A tendency such as an increase in curing shrinkage tends to occur.

The number average molecular weight of the epoxy resin is preferably from 280 to 440, and more preferably from 320 to 380, from the viewpoint that a low-viscosity resin composition can be obtained and the physical properties are well balanced. . If the number average molecular weight is too small, the strength of the cured product tends to be low, and the moisture resistance tends to be low. If the number average molecular weight is too large, the viscosity of the resin composition tends to be high.

Further, the epoxy equivalent of the epoxy resin is preferably from 140 to 220, more preferably from 160 to 190, from the viewpoint that the compounding amount of the curing agent falls within an appropriate range. If the epoxy equivalent is too small, the compounding amount of the curing agent becomes too large, and the properties of the cured product tend to deteriorate, and if too large, the compounding amount of the curing agent decreases and the molecular weight of the epoxy resin itself increases. Tend to increase and the viscosity of the resin composition tends to increase.

Specific examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, glycidylamine type epoxy resin, and alicyclic type epoxy resin. Epoxy resins, dicyclopentadiene-type epoxy resins, phenol novolak-type epoxy resins, polyether-modified epoxy resins, copolymers with other polymers such as silicone-modified epoxy resins, and the like can be given. Among these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, number average molecular weight of 100
A phenol novolak-type epoxy resin having a molecular weight of 400 or more and having two or more epoxy groups in a molecule is preferred from the viewpoints of relatively low viscosity, excellent heat resistance and excellent moisture resistance.

Examples of the reactive diluent include resorcin diglycidyl ether, tert-butylphenyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, 3-glycidoxypropyltrimethoxysilane, Glycidoxypropylmethyldimethoxysilane, 1- (3-glycidoxypropyl) 1,1,3,
3,3-pentamethyldisiloxane, N-glycidyl-
Monoglycidyl compounds such as N, N-bis [3- (trimethoxysilyl) propyl] amine and monoalicyclic epoxy compounds such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

Examples of the other epoxy compounds include hydroquinone diglycidyl ether, 2,5-di-tert-butylhydroquinone diglycidyl ether, butanediol diglycidyl ether, butenediol diglycidyl ether, butynediol diglycidyl ether, and glycerin. Alkylene glycidyl ethers such as triglycidyl ether, trimethylolpropane triglycidyl ether and pentaerythritol tetraglycidyl ether; 1,3-diglycidyl-5,5
Glycidyl group-containing hydantoin compounds such as -dialkylhydantoin, 1-glycidyl-3- (glycidoxyalkyl) -5,5-dialkylhydantoin, glycidyl esters such as diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl ester of dimer acid, Glycidyl group-containing amino compounds such as tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenylmethane, triglycidyl-m-aminophenylmethane, diglycidylaniline, diglycidyltoluidine, tetraglycidyl-m-xylylenediamine, 1,3 -Bis (3-glycidoxypropyl)
-1,1,3,3-tetramethyldisiloxane, α, ω
Glycidyl group-containing siloxanes such as -bis (3-glycidoxypropyl) polydimethylsiloxane;

If the reactive diluent and other epoxy compounds are used in large amounts, the moisture resistance and heat resistance of the cured product will deteriorate, so that 30% (% by weight, hereinafter the same) or less in the component (A), It is preferable that the content be 15% or less.

The curing agent diethyltoluenediamine (B) contained in the epoxy resin composition for semiconductor encapsulation (I)
(Hereinafter also referred to as DETDA) has a structure in which a phenyl group of toluene is substituted with two amino groups and two ethyl groups, for example,

[0021]

Embedded image

An aromatic amine compound having the following structure:

Since DETDA is an amine compound, the resin composition has a lower hygroscopicity than an acid anhydride and does not form an ester bond by a curing reaction, so that a cured product having excellent moisture resistance can be obtained. . In addition, since it is an aromatic amine compound, compared with the case of an aliphatic amine compound, the storage stability of the resin composition is improved, and
The heat resistance of the cured product increases. Furthermore, although many aromatic amine compounds are solid, DETDA is not a solid but a low-viscosity liquid despite being an aromatic amine compound, so that the viscosity of the resin composition can be reduced. In addition, since the reactive group is an amino group, it has excellent adhesiveness to metals as compared with the case where an acid anhydride is used as a curing agent.

There are a plurality of structural isomers in DETDA, and among them, particularly, 3,5-diethyl-
2,6-Toluenediamine (hereinafter, also referred to as 2,6-TDA), 3,5-diethyl-2,4-toluenediamine (hereinafter, also referred to as 2,4-TDA), and a mixture thereof are preferable. Among the above mixtures, especially 2,6-TD
Those having an A / 2,4-TDA of 30/70 to 10/90 (hereinafter also referred to as component (B-1)) are preferable from the viewpoint of easy availability.

The amount of the component (B) to be used with respect to the component (A) is not particularly limited, as long as the compounding ratio can exhibit the characteristics of the composition of the present invention. It is preferable to mix the active hydrogen of the component (B) in a range of 0.7 to 1.4 equivalents, more preferably 0.9 to 1.3 equivalents. If the active hydrogen equivalent is more than 1.4 equivalents, the content of the epoxy compound in the composition becomes too small, which tends to cause poor curing, weakening of the cured product, and the like. .7 equivalents,
This tends to increase the viscosity of the resin composition.

Since the epoxy resin composition (I) of the present invention is used for semiconductor encapsulation, it is generally a one-part type in terms of good workability and the like, and is a mixture of the component (A) and the component (B). Has a viscosity of 500 to 100,000 cP at 25 ° C.,
It is preferable to use a liquid material having a viscosity of 00 to 3000 cP from the viewpoint that a large amount of an inorganic filler can be incorporated.

The epoxy resin composition (I) of the present invention comprises
Various curing accelerators (C) for accelerating the curing reaction between the component (A) and the component (B) can be added and used as the epoxy resin composition (II) of the present invention. However, in order to form a one-pack type resin composition, it must have some potential.

Examples of the accelerator include phenol compounds such as nonylphenol and bisphenol A.
Imidazole compounds such as -methylimidazole and 2-ethyl-4-methylimidazole; and organic metal compounds such as tris-acetylacetonatomanganese (III) and tris-acetylacetonatocobalt (III). These may be used alone or in combination of two or more. Among these, bisphenol A, tris-acetylacetonatocobalt (III) and the like are preferable, and tris-acetylacetonatocobalt is particularly preferable because of its excellent potential and curing promoting effect. When tris-acetylacetonatocobalt (III) is used, it has sufficient storage stability at room temperature (about 25 ° C.) or lower, preferably at −20 ° C. or lower.
When the temperature reaches 00 to 200 ° C., and more preferably 130 to 170 ° C., the effect is obtained that the curing reaction proceeds promptly.

The amount of the component (C) used is not particularly limited as long as the above-mentioned promoting effect can be obtained, but is not particularly limited, and 100 parts (part by weight, hereinafter the same) of the component (A) is added to the component (C). Is preferably 0.3 to 7 parts, more preferably 1 to 3 parts.
Use of more than 7 parts does not improve the accelerating effect, but rather tends to cause unfavorable tendencies such as poor storage stability. When the amount is less than 0.3 part, a sufficient accelerating effect tends not to be obtained. Is more likely to occur.

Since the amount of the component (C) added to the resin composition (I) of the present invention is small, the viscosity at 25 ° C. of the resin composition (II) of the present invention is different from that of the composition (I). Almost the same level is a little higher, and it is often a liquid of 500 to 150,000 cP, more preferably 800 to 4500 cP.

The resin compositions (I) and (II) of the present invention include:
Various inorganic fillers can be blended to reduce the coefficient of thermal expansion of the cured product, increase the strength, and the like.

Examples of the inorganic filler include fused silica powder, quartz glass powder, crystalline silica powder, glass fiber, alumina powder, and talc. Among these, the use of spherical fused silica powder having an average particle size of 10 to 20 μm can effectively suppress the increase in viscosity of the resin composition due to filling, and is effective because the coefficient of thermal expansion of itself is small. This is preferable in that the thermal expansion coefficient of the cured product can be reduced.

When the inorganic filler is used, the filling rate of the inorganic filler is generally 70 to 80% of the whole composition.

The epoxy resin compositions (I) and (II) of the present invention may contain additives such as various coupling agents, defoaming agents, leveling agents, low-stress agents, and pigments, if necessary. It can also be blended.

Further, a part of the component (B) contained in the epoxy resin compositions (I) and (II) of the present invention may be replaced with an amino compound other than the component (B). In this case, it is preferable to replace part of the component (B) with another amino compound so that the equivalent ratio of the component (A) to the component (B) is maintained. The amount of the amino compound used other than the component (B) is 30% or less of the component (B) in an equivalent amount,
Further, it is preferably at most 15%. If it exceeds 30%,
The effect of using the component (B) tends to be reduced.

The epoxy resin composition of the present invention is obtained by uniformly mixing the component (A), the component (B) and, if necessary, the component (C), fillers, additives and the like with a kneader, a mixer, a three-roll mill or the like. Can be obtained. The resin composition thus obtained has fluidity suitable for encapsulating a semiconductor by a method such as coating with a dispenser, screen printing, potting, and underfill, has a small hygroscopic property, and has excellent heat resistance. It can provide a cured product having water resistance and moisture resistance.

The heating conditions for thermally curing the uniformly mixed resin composition are not particularly limited as long as the characteristics of the present invention can be exhibited. (C)
When curing without using components, for example, 1
20 to 200 ° C, more preferably 150 to 180 ° C for 1 to 4 hours. When the component (C) is used, a relatively low temperature, for example, 100 to 190 ° C, furthermore, 130 to 160 ° C for 1 to 4 hours. It is. In order to suppress curing shrinkage and reduce residual stress, it is preferable to perform step curing in which the temperature is gradually raised to the temperature range in several stages.

The cured product thus obtained has, for example, a glass transition temperature (Tg) of 110 ° C. or higher, and
30 ° C. or higher.

In a preferred embodiment of the resin composition of the present invention, in the case of a resin composition containing the component (A) and the component (B), for example, EPC830 is used as the component (A).
100 parts of LVP (bisphenol F type epoxy resin, manufactured by Dainippon Ink and Chemicals, Inc.) and 2,6-TDA / 2,4-TDA as a component (B) in 30/70 to 1
0/90 DETDA mixture (B-1) is 20-
40 parts, more preferably 25 to 35 parts. In the case of the composition, the viscosity at 25 ° C. is 700 to
1600 cP, more preferably 1000 to 1300 cP, Tg of 110 ° C. or more as a cured product, further 130 ° C.
That is all. In the case of a resin composition containing the components (A), (B) and (C), for example, 100 parts of EPC830LVP as the component (A) and the above-mentioned (B- 1) Component is 20 to 40
Part, further 25 to 35 parts, tris- as component (C).
A compound in which 1 to 3 parts, further 1.5 to 2.5 parts of acetylacetonatocobalt (III) is blended is exemplified. In the case of the composition, the viscosity at 25 ° C is 700 to 2000.
cP, furthermore, 1000 to 1600 cP, and Tg when a cured product is obtained, are 130 ° C. or more, and further 150 ° C. or more.

[0040]

Next, the resin composition of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The relationship between the components used in the following Examples and Comparative Examples and their abbreviations is shown below.

(A) Component EPC830 LVP: bisphenol F type epoxy resin (epoxy equivalent: 162, Dainippon Ink and Chemicals, Inc.)
(B) Component Epicure-W: a mixture of 3,5-diethyl-2,6-toluenediamine / 3,5-diethyl-2,4-toluenediamine in 20/80 (active hydrogen equivalent: 45, oiled shell) (C) Component BPA: Bisphenol A 2P4MHZ: Imidazole derivative (manufactured by Shikoku Chemical Industry Co., Ltd.) 2MZ: 2-methylimidazole Co-AA: Tris-acetylacetonato cobalt (II)
I) Other components Me-HHPA: Methyl hexahydrophthalic anhydride (acid anhydride equivalent: 168, manufactured by Hitachi Chemical Co., Ltd.) SL-A-187: Epoxy silane coupling agent (manufactured by Nippon Unicar Co., Ltd.) FB201S: spherical fused silica powder having an average particle size of 13 μm (manufactured by Denki Kagaku Kogyo KK) The evaluation methods used in the following Examples and Comparative Examples are shown below.

(Viscosity) In Examples 1 to 8, the viscosity of the composition immediately after preparation with an E-type viscometer (initial viscosity) and the viscosity of the composition after standing at 25 ° C. for 1 day (viscosity after standing for 1 day) ) Was measured.

In Example 9 and Comparative Example 1, SS
The initial viscosity was measured with an A-type viscometer at rotation speeds of 5 rpm and 50 rpm.
m. All measurements were performed at 25 ° C.

(Viscosity increase rate) The viscosity / initial viscosity after standing for one day was defined as the viscosity increase rate.

(Fluidity) 0.2 g of the composition was molded on a slide glass which had been washed with acetone,
After leaving it to stand for 0 minute and allowing it to flow and spread naturally, it was cured and then the height of the top of the cured product (glove height (GH)) was measured with a vernier caliper. G. FIG. H. The smaller the value, the better the fluidity.

(Adhesiveness) The composition was applied to a plate-shaped square silicon mirror chip having a thickness of 0.5 mm and a side of 2 mm so as to have a thickness of 50 μm, and bonded to the same silicon mirror chip substrate. C. for 3 hours to adhere, then shear strength (Ch) with a die shear tester.
ip-Bonding-Strength (CBS))
Was measured.

(Glass transition temperature (Tg) of cured product) The cured product obtained by heating the composition at 150 ° C for 3 hours was subjected to DSC.
The Tg was determined from the inflection point of the obtained specific heat curve by analyzing with a device (differential scanning calorimeter) at a heating rate of 16 ° C./min.

(Hygroscopicity of the composition)
mφ iron can, left in a constant temperature / humidity bath at 25 ° C / 90 RH% for a predetermined period of time, and the rate of weight increase was determined for each time period.
The composition was made hygroscopic.

(Moisture resistance of cured product)
40mmφ × 5mm cured product obtained by heating for hours,
In a PCT test, the substrate was exposed to a condition of 120 ° C./2 atm for a predetermined time, and Tg was measured at each time in the same manner as described above.
A decrease in Tg indicates that the cured product has low moisture resistance and the cured product has deteriorated.

Examples 1 to 8 Each component shown in Table 1 was mixed to have the composition shown in Table 1 to prepare a uniform resin composition.

The viscosity, rate of increase in viscosity and Tg of the cured product of the obtained composition were measured. Table 1 shows the results.

[0053]

[Table 1]

Example 9 and Comparative Example 1 The components shown in Table 2 were mixed so as to have the composition shown in Table 2 to prepare a uniform resin composition.

The viscosity, fluidity, hygroscopicity,
The Tg, adhesion, and moisture resistance of the cured product were measured. Table 2 shows the results.

[0056]

[Table 2]

[0057]

Since the epoxy resin composition of the present invention uses diethyltoluenediamine as a curing agent, it is stable against moisture, and has a low viscosity and good storage stability. The cured product has high heat resistance, high moisture resistance, and exhibits excellent adhesiveness.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hirofumi Nishida 236 Nakai, Tatsuno-cho, Tatsuno-shi, Hyogo Nagase Ciba Co., Ltd. F-term in Tatsuno Plant (reference) 4J036 AA01 AA02 DA02 DB06 DC10 DC40 FA11 GA07 JA07 4M109 AA01 BA01 CA21 EA03 EB02 EB04 EB06 EB08 EB09 EB12 EB19 EC01 EC04 EC05 EC09 EC14

Claims (3)

[Claims] 1. An epoxy resin composition for semiconductor encapsulation comprising (A) an epoxy compound and (B) diethyltoluenediamine. 2. The epoxy resin composition according to claim 1, further comprising (C) a curing accelerator. 3. The epoxy resin composition according to claim 2, wherein the component (C) is tris-acetylacetonatocobalt (III).