JP2000017149A - Liquid epoxy resin composition for sealing medium and its cured product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid sealing medium capable of preventing defective articles from being produced even in being subjected to pressure cooker test or a thermal cycle shock test, capable of improving the reliability in semiconductors, and having low viscosity and long pot life. SOLUTION: This liquid epoxy resin composition for sealing medium contains (A) a diallyl bisphenol-based liquid epoxy resin, (B) an aromatic amine-based hardener being liquid at an ordinary temperature, (C) a silane coupling agent having at least one of functional groups selected from a group consisting of an epoxy group, an amino group, a mercapto group, a vinyl group and methacryl group, (D) a silicone resin having hydroxyl group as a functional group and (E) an inorgnaic filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid epoxy resin composition for a sealing material used for sealing a semiconductor.

[0002]

2. Description of the Related Art A liquid sealing material is used for sealing, for example, a plastic pin grid array (hereinafter, referred to as PPGA) type semiconductor, a plastic multi-chip module (hereinafter, referred to as PMCM) type semiconductor, or the like. However, the reliability is not enough compared with the hermetic sealing type made of ceramics, and dual in-line (hereinafter referred to as DIP)
The spread of plastic packages has been delayed compared to molds.
The cause of the decrease in the reliability of the PPGA type semiconductor and the PMCM type semiconductor is that unlike the transfer molding of the DIP type package in which moisture enters from the packaged organic printed wiring board, the liquid sealing under no pressure is performed. The sealing material flows into the package and is molded, leaving bubbles in the resin and causing cracks when thermal stress is applied. The thermal expansion due to the difference in the coefficient of linear expansion between the resin, the semiconductor chip, and the organic substrate When a stress is applied, there is a problem that separation occurs at an interface to facilitate entry of moisture. In addition, in order to match the coefficient of linear expansion with the semiconductor substrate, many studies have been made to adjust the size, shape, and content of the inorganic filler to prevent any mismatch, but to achieve the intended effect. Was not possible.

[0003]

SUMMARY OF THE INVENTION According to the present invention, defective products are not generated even in accelerated tests such as a pressure cooker test (hereinafter, referred to as PCT) and a thermal cycle test (hereinafter, referred to as HC). The present invention provides a liquid epoxy resin composition for a sealing material, which can greatly improve the reliability of a sealing material and has a low viscosity and a long pot life.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above-mentioned object, and as a result, completed the present invention. That is, the present invention provides (1) (a) a diallyl bisphenol type liquid epoxy resin, (b) an aromatic amine-based curing agent which is liquid at room temperature, (c) an epoxy group, an amino group, a mercapto group, and a vinyl group. And a silane coupling agent having one or more functional groups selected from the group of methacrylic groups, (d) a silicone resin having a hydroxyl group as a functional group, and (e) a liquid epoxy resin composition for a sealing material containing an inorganic filler. The liquid epoxy resin composition for a sealing material according to (1), wherein the diallyl bisphenol-type liquid epoxy resin is diallyl bisphenol A diglycidyl ether or diallyl bisphenol F diglycidyl ether. (3) (e) the average particle size of the inorganic filler is 1 to 1
0 μm and the content of the inorganic filler having a particle size of 30 μm or more is 20% by weight or less in all the filler components, and the content of the inorganic filler having a particle size of 1 μm or less is 5 to 40% by weight in all the filler components. % Of the liquid epoxy resin composition for a sealing material according to (1) or (2), (4) a cured product of the liquid epoxy resin composition for a sealing material according to (1) to (3), 5)
A semiconductor device having the cured product according to (4).

[0005]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, (a) a diallyl bisphenol type liquid epoxy resin is used as an epoxy resin. Examples of the diallyl bisphenol type liquid epoxy resin include diallyl bisphenol A diglycidyl ether and diallyl bisphenol F diglycidyl ether. These resins are liquid at room temperature and can be obtained by reacting diallyl bisphenol A or F with epichlorohydrin.
Ionic impurities such as Na + and Cl − of the epoxy resin are as follows:
In order to obtain a liquid sealing material having excellent reliability, it is preferable to use as little as possible.

In the present invention, a liquid epoxy resin other than the above (a) diallyl bisphenol diglycidyl ether type liquid epoxy resin may be used as the epoxy resin. (A) diallyl bisphenol diglycidyl ether
As liquid epoxy resins other than ter epoxy resins,
For example, bisphenol A diglycidyl ether type epoxy resin, bisphenol F diglycidyl ether type epoxy resin, bisphenol S diglycidyl ether type epoxy resin, 3,3 ′, 5,5′-tetramethyl-4,
4'-dihydroxybiphenyldiglycidyl ether type epoxy resin, 4,4'-dihydroxybiphenyldiglycidyl ether type epoxy resin, 1,6-dihydroxybiphenyldiglycidyl ether type epoxy resin, phenol novolak type epoxy resin Resins, bromine-type cresol novolak-type epoxy resins, and bisphenol D-diglycidyl ether-type epoxy resins. From the viewpoint of pot life, the amount used is preferably from 0 to 90% by weight, and more preferably from 20 to 90% by weight, based on all epoxy resins used. These may be used alone or in combination. Further, in order to obtain a liquid sealing material having excellent reliability, it is preferable that ionic impurities such as Na + and Cl − of the epoxy resin are as small as possible.

The curing agent (b) used in the present invention is an aromatic amine curing agent. Amines having no aromatic ring are poor in heat resistance and have a fatal disadvantage that they have poor storage stability due to their high reactivity even in an atmosphere at a temperature of zero or less, and are not suitable for the present invention. As the aromatic amine-based curing agent (b), any aromatic amine-based curing agent that is liquid at room temperature can be used, but alkylated diaminodiphenylmethane is particularly preferred. As the alkyl group, a C1 to C4 alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group is preferable.
Further, it is preferable that this alkyl group be bonded to phenyl. For example, 4,4'-diamino-3,3'-diethyldiphenylmethane can be mentioned. Further, in order to obtain a liquid sealing material having excellent reliability, the amine-based curing agent is Na +,
It is preferable that ionic impurities such as Cl- be as small as possible. The mixing molar ratio of the total epoxy resin and the curing agent (b) aromatic amine-based curing agent is determined based on the moisture resistance and curability due to the remaining unreacted amino groups in the curing agent. Assuming that the aromatic amine type curing agent is 1, the total epoxy resin is 0.1.
9 to 1.2 is desirable.

(C) As a silane coupling agent having at least one functional group selected from the group consisting of an epoxy group, an amino group, a mercapto group, a vinyl group and a methacryl group in a molecule, for example, epoxy silane is preferable. Further, when it is desired to increase the adhesion to the substrate according to the application, aminosilane, vinylsilane, and methacrylsilane may be used as necessary. Two or more of these coupling agents may be used in combination. The amount used is 2.5 wt% or more of the total liquid sealing material.
0.5 wt% is better and more preferably 1.5 wt% to 1 w
t%.

(D) The silicone resin having a hydroxyl group as a functional group is a low molecular weight silicone resin intermediate which has reactivity with various organic resins and monomers.
For example, SH-6018 (manufactured by Dow Corning Toray) may be mentioned. From the viewpoint of viscosity and adhesion,
10 wt% to 0.5 wt% of the total liquid sealing material is good, and more preferably 5 to 1 wt%. It is more preferable to add aluminum chelate as a catalyst.

(E) As the inorganic filler, for example, crystalline silica, fused silica or the like is used. The shape generally has a spherical shape, a crushed shape, a flake shape, etc., but the linear expansion coefficient can be reduced by adding more filler, and in order to improve the effect, a spherical inorganic filler is used. The agent is best. The best addition amount is 50 to 80 wt% of the total liquid sealing material. 5
If it is less than 0 wt%, the effect of reducing the coefficient of linear expansion is small, and
If the content exceeds wt%, the viscosity of the liquid resin becomes too high, making it difficult to use the resin at a practical level.

Further, by adjusting the particle size distribution of the filler, it is possible to maximize the flow characteristics such as viscosity. It is generally known that a filler having a particle size distribution having a wide distribution range and a filler having a large particle size tend to have a lower viscosity. However, for the purpose of lowering the viscosity,
For example, a filler having only a large particle size of 60 μm or more has a low viscosity, but a relatively heavy filler sinks during curing, and the composition ratio between the top and bottom of the cured product is different, so-called filler sedimentation. Occurs. Another drawback is that if a filler having a large particle size is used, it will not flow into a narrow gap. In recent years, as represented by a PPGA type package, the number of pins has been reduced or the space has been reduced, and the pitch between wires has become narrower. In such a situation, the particle size of the filler must be reduced in order to allow the liquid sealing material to flow under no pressure and to be formed without any fluidity problems such as voids and unfilling. However, there are many disadvantages that the fluidity is impaired by reducing the particle size. Therefore, the average particle size of the filler is 1 to 10
μm, which is smaller than that of the conventional liquid sealing material, and those having a particle size of 30 μm or more account for 20% by weight or less of the total filler component, and those having a particle size of 1 μm or less represent 5 to 40% of the total filler component.
By adjusting the particle size so as to be% by weight, the fluidity is not impaired. If the average particle size is less than 1 μm, the viscosity at the time of molding becomes high and the fluidity is impaired. If it exceeds 10 μm, the reliability of the semiconductor deteriorates. In addition, the particle size is 30 μm
If the above content exceeds 20% by weight of the total filler component, the reliability is similarly deteriorated. For particles having a particle size of 1 μm or less, 5 to 40% by weight of the total filler component and an appropriate amount of fine filler are added and the particle size distribution is adjusted to suppress the phenomenon that the fine filler sinks during curing. it can. If the content of 1 μm or less is less than 5% by weight of the total filler component, there is no effect of suppressing the sedimentation of the filler, and if it exceeds 40% by weight, the viscosity becomes too high and molding becomes difficult.

[0012] The liquid epoxy resin composition for a sealing material of the present invention may further contain, if necessary, other resins, diluents, pigments, coupling agents, flame retardants, leveling agents, An additive such as a foaming agent may be used. The liquid sealing material is manufactured by dispersing and kneading the components, additives, and the like in a planetary mixer and performing a vacuum defoaming treatment.

The cured product of the present invention is obtained by curing the above liquid epoxy resin composition for a sealing material. Hardening is usually 7
It is desirable to cure at 0 ° C to 200 ° C, preferably at 80 ° C to 160 ° C. The curing time is usually 30 minutes to 24 hours,
Preferably, it is 1 hour to 10 hours. In some cases, step curing is also suitable. Further, a semiconductor device of the present invention has a cured product of the above-mentioned liquid epoxy resin composition for a sealing material. In order to manufacture this semiconductor device, for example, the liquid epoxy resin composition for a sealing material may flow into a package under no pressure and be cured. Examples of the semiconductor device include a chip size package, a ball grid array, a pin grid array, and a multi-chip module.

[0014]

Next, the present invention will be specifically described with reference to Examples and Comparative Examples. Examples 1 and 2 The following raw materials were stirred in a vacuum at a ratio shown in Table 1 with a planetary mixer to obtain a liquid epoxy resin composition for a sealing material. The viscosity and storage stability of the obtained liquid epoxy resin composition for a sealing material were evaluated. Further, the PPGA package is sealed with the obtained liquid epoxy resin composition for a sealing material, and cured in an oven at 100 ° C. × 2 hours + 150 ° C. × 2 hours to obtain a semiconductor package. Was. This semiconductor package
The state of the peeling and cracking of the cured liquid epoxy resin composition for a sealing material in the resin was measured after 500 hours of PCT treatment.
Observations were made after 1000 cycles of C and before the treatment.
Table 2 shows the evaluation results.

Comparative Examples 1 and 2 The following raw materials were stirred in a vacuum at a ratio shown in Table 1 with a planetary mixer to obtain a liquid sealing material. The PPGA package is sealed with the obtained liquid sealing material,
The composition was cured in an oven at 2 ° C. × 2 hours + 150 ° C. × 2 hours to obtain a semiconductor package. In addition, the same evaluation as in the examples was performed. Table 2 shows the evaluation results.

[0016]

Table 1 Ingredients Example Comparative Example 12 1 · diallyl bisphenol A diglycidyl ether 1) 100 60 · bisphenol F diglycidyl ether type epoxy resin 2) 40 100 · alkylated diaminodiphenylmethane 3) 30 35 40 • Glycidyltrimethoxysilane 55 5 • Polyalkylphenylsiloxane 4) 55 • Aluminum chelate 0.5 0.5 • Fused silica 320 320 320 • Carbon black 111

1) Diallyl bisphenol A diglycidyl ether type epoxy resin (epoxy equivalent 218): Nippon Kayaku Co., Ltd. 2) Bisphenol F diglycidyl ether type epoxy resin: epoxy equivalent 163 3) Alkylated diaminodiphenylmethane curing agent: 4,
4'-diamino-3,3'-diethyldiphenylmethane, amino equivalent 65 4) Polyalkylphenylsiloxane: SH-6018 manufactured by Toray Dow Corning

[0018]

[Table 2]

Evaluation method: Viscosity: The value measured at 10 rpm with an E-type viscometer (25 ° C.) was taken as a value. The higher the value, the worse. -Storage property: Time was taken for the viscosity to be twice the initial viscosity. ○
Is 72 hours or more, Δ is 24-72 hours, and X is 24 hours or less. -Peeling and cracking after curing: before treatment, PCT treatment (1
(At 30 ° C., 2.5 atm) after 500 hours. C1000
After the cycle (−65 ° C./30 minutes and 150 ° C./30 minutes were alternately repeated 1000 times), the presence or absence of peeling and cracks between the semiconductor chip and the printed board interface was confirmed using an ultrasonic microscope. The number of evaluated PPGA packages is 10.

[0020]

The liquid epoxy resin composition for encapsulant of the present invention has a low viscosity and, when encapsulating a semiconductor, can be used in a pressure cooker test and a thermal cycle test.
A highly reliable semiconductor without peeling or cracking can be obtained, and is useful as a liquid sealing material.

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Claims (5)

[Claims] (1) a diallyl bisphenol type liquid epoxy resin, (b) an aromatic amine curing agent which is liquid at room temperature, (c) an epoxy group, an amino group, a mercapto group, a vinyl group and a methacryl group. A liquid epoxy resin composition for a sealing material, comprising: (d) a silicone resin having a hydroxyl group as a functional group; and (e) an inorganic filler. 2. The liquid epoxy resin composition for a sealing material according to claim 1, wherein the diallyl bisphenol type liquid epoxy resin is diallyl bisphenol A diglycidyl ether or diallyl bisphenol F diglycidyl ether. object. 3. An inorganic filler having an average particle size of 1 to 10 μm.
m, and the content of the inorganic filler having a particle size of 30 μm or more is 20% by weight or less in all the filler components, and the content of the inorganic filler having a particle size of 1 μm or less is 5 to 40% by weight in all the filler components. %
The liquid epoxy resin composition for a sealing material according to claim 1 or 2, wherein 4. A cured product of the liquid epoxy resin composition for a sealing material according to any one of claims 1 to 3. 5. A semiconductor device having the cured product according to claim 4.