JP2658750B2 - Thermosetting resin composition and semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin composition which provides a cured product having good flowability, small expansion coefficient, high glass transition temperature, good adhesion and low moisture absorption. And a semiconductor device sealed with a cured product of the thermosetting resin composition.

[0002]

2. Description of the Related Art
In the semiconductor industry, resin-sealed diodes, transistors, ICs, LSIs, and ultra-LSIs are the mainstream. Among them, epoxy resins are generally more moldable, adhesive, and have better electrical properties than other thermosetting resins. Due to its excellent mechanical properties, moisture resistance, etc., semiconductor devices are often sealed with epoxy resin compositions, but these semiconductor devices have recently become more and more integrated, Chip dimensions are also increasing. On the other hand, package external dimensions are becoming smaller and thinner with the demand for smaller and lighter electronic devices. Further, in the method of attaching a semiconductor component to a circuit board, the surface mounting of the semiconductor component has been widely performed due to the high density of components on the substrate and the thinning of the substrate.

[0003] However, when a semiconductor device is surface-mounted, it is common to immerse the entire semiconductor device in a solder bath or to pass the semiconductor device through a high-temperature zone in which the solder is melted. Cracks occur in the layer, and peeling occurs at the interface between the lead frame or chip and the sealing resin. Such cracks and peeling become more remarkable when the sealing resin layer of the semiconductor device absorbs moisture before the thermal shock at the time of surface mounting. Therefore, the reliability of the semiconductor device sealed with the epoxy resin composition after mounting may be greatly impaired. Therefore, it is desired to solve these problems.

The present invention has been made in view of the above circumstances, and has a good fluidity, a low expansion coefficient, a low stress, a high glass transition temperature, a good adhesive property, and a low hygroscopicity. An object of the present invention is to provide a thermosetting resin composition that gives a cured product and a semiconductor device that has high reliability in thermal shock and moisture resistance during surface mounting sealed with the cured product of the thermosetting resin composition. And

[0005]

The present inventor has conducted intensive studies to achieve the above object, and as a result, as a epoxy resin, a non-cyclohexane type epoxy resin having two or more epoxy groups in one molecule has been prepared. 95 parts (parts by weight, hereinafter the same) and 5 to 80 parts of a cyclohexane type epoxy resin represented by the following formula (1) are used in combination, and each molecule has two or more phenolic hydroxyl groups in one molecule and has a naphthalene ring. By blending a phenolic resin and an inorganic filler, it has good fluidity, high adhesiveness, low expansion coefficient, high glass transition temperature, and thermosetting that gives a cured product with low moisture absorption. It has been found that a conductive resin composition is obtained, and that a semiconductor device having excellent reliability can be obtained by sealing with a cured product of the thermosetting resin composition.

[0006]

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[0007] A resin composition containing a cyclohexane type epoxy resin (JP-A-3-14815) has a higher heat resistance than a conventional epoxy resin composition and gives a cured product having low water absorption. It is difficult to say that it is possible, and it has been difficult to obtain high reliability in thermal shock and moisture resistance during surface mounting. Furthermore, even if the cyclohexane type epoxy resin is used alone, the adhesiveness and low water absorption are improved, but a cured product having a low glass transition temperature is provided because the crosslink density is not increased. On the other hand, the present inventor has determined that a cyclohexane type epoxy resin represented by the above formula (1) and a non-cyclohexane type epoxy resin having two or more epoxy groups in one molecule, particularly a naphthalene ring-containing epoxy resin, have a specific ratio. By using a naphthalene ring-containing phenol resin as a curing agent, a thermosetting resin composition that surprisingly has a high glass transition temperature, has extremely low water absorption, and gives a cured product with good adhesiveness can be obtained. This has led to the achievement of the present invention.

Accordingly, the present invention relates to (a) 20 to 95 parts of a non-cyclohexane type epoxy resin having two or more epoxy groups in one molecule and 5 to 80 parts of a cyclohexane type epoxy resin represented by the above formula (1). (B) a phenolic resin having two or more phenolic hydroxyl groups in one molecule and having a naphthalene ring,
(C) Provided are a thermosetting resin composition characterized by blending an inorganic filler, and a semiconductor device sealed with the cured product.

Hereinafter, the present invention will be described in more detail. In the thermosetting resin composition of the present invention, a non-cyclohexane type epoxy resin having two or more epoxy groups in one molecule and a cyclohexane type epoxy resin are used as epoxy resins. Mix.

The non-cyclohexane type epoxy resin having two or more epoxy groups in one molecule of the first essential component includes bisphenol A type epoxy resin, phenol novolak type epoxy resin, triphenol alkane type epoxy resin and The polymer, dicyclopentadiene-modified phenol type epoxy resin, phenol aralkyl type epoxy resin, glycidyl ester type epoxy resin, naphthalene ring-containing epoxy resin, alicyclic epoxy resin, heterocyclic type epoxy resin, brominated epoxy resin, bishydroxy Examples include biphenyl-based epoxy resins.
In particular, among these epoxy resins, a naphthalene ring-containing epoxy resin represented by the following formula is desirable for obtaining low moisture absorption and high adhesiveness.

[0011]

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The epoxidized α-naphthol or α, β-naphthol in the above naphthalene ring-containing epoxy resin is preferably not more than 10% (% by weight, the same applies hereinafter), and from the viewpoint of heat resistance and moisture resistance. Desirably, it is 7% or less. In addition, the content of a binuclear substance or phenylglycidyl ether consisting of only phenol is preferably 0.5% or less, particularly preferably 0.2% or less.

The softening point of the naphthalene ring-containing epoxy resin is affected by the epoxide content of α-naphthol and α, β-naphthol in the naphthalene ring-containing epoxy resin. 120
C., especially 70-110 ° C., epoxy equivalent of 100-40.
Those having 0 are desirable. When an epoxy resin having a softening point of less than 50 ° C. is used, not only does the glass transition temperature of the cured product decrease, but burrs and voids may easily occur during molding, and if the softening point exceeds 120 ° C., the viscosity may decrease. It may be too high to be molded.

When these resins are used for semiconductor encapsulation, the content of hydrolyzable chlorine is 1000 ppm or less, especially 500 ppm.
It is preferable that the content of sodium and potassium is 10 ppm or less. Hydrolytic chlorine is 1000ppm
If the semiconductor device is sealed with a resin exceeding 10 ppm or sodium and potassium exceeding 10 ppm and the semiconductor device is left under high temperature and high humidity for a long time, the moisture resistance may be deteriorated.
By selecting such an epoxy resin, a thermosetting resin composition having excellent reliability can be obtained.

Specific examples of such a naphthalene ring-containing epoxy resin include the following compounds.

[0016]

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In order to obtain a resin composition having very low water absorption and good adhesiveness, the content of naphthalene rings in these epoxy resins is 5 to 80%, particularly 10 to 80%.
It is desirable that the content be in the range of 60%, and it is preferable to adjust the blending amount of the naphthalene ring-containing epoxy resin within this range.

Further, the second essential component of the present invention is a cyclohexane type epoxy resin represented by the following formula (1).

[0019]

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In the above formula (1), n of the repeating unit is an integer of 0 to 3, but is preferably 1 to 3 in order to achieve both low viscosity and high Tg. If the number of repeating units exceeds 3, the viscosity may be too high and molding workability may be poor.

The cyclohexane type epoxy resin of the above formula (1) has an epoxy equivalent of 220 to 235 and a softening point of 60.
It is preferably in the range of 70 to 70.

The compounding amount of the cyclohexane type epoxy resin of the above formula (1) is 5-8% of the total epoxy resin in the composition.
0%, especially 10 to 60%. If the amount is less than 5%, sufficient adhesiveness and water absorption cannot be obtained, and if it is more than 80%, the adhesiveness is good but the glass transition temperature is low.

Next, a phenolic resin having two or more phenolic hydroxyl groups in one molecule of the third essential component and having a naphthalene ring acts as a curing agent for the epoxy resin of the first and second components. It is. As the naphthalene ring-containing phenol resin, those having the following general formula are particularly exemplified.The water absorption rate is significantly reduced by combining the naphthalene ring-containing phenol resin and the cyclohexane type epoxy resin represented by the following general formula, and the adhesive strength is lowered. The combination of the improvement and the low water absorption makes it possible to exhibit excellent characteristics of crack resistance during solder immersion after moisture absorption.

[0024]

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The following are typical examples of these phenolic resins.

[0026]

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These phenolic resins have a softening point of 60 to
Those having a temperature of 150 ° C. are preferred, more preferably 70 ° C.
1300 ° C. The hydroxyl equivalent is 90-
250 are preferred. When this phenol resin is used for semiconductor encapsulation, sodium and potassium are 10 pp
m or less, and when the semiconductor device is sealed with a resin containing more than 10 ppm of sodium and potassium, and the semiconductor device is left under high temperature and high humidity for a long time, deterioration of moisture resistance may be promoted.

It should be noted that other phenol resins may be blended within a range that does not impair the effects of the present invention.

The mixing ratio between the epoxy resin and the phenol resin is determined by the equivalent ratio between the epoxy group and the hydroxyl group. In the present invention, the epoxy group / hydroxyl group is 0.5 to
2, particularly preferably in the range of 0.8 to 1.5,
Normally 30 parts of phenol resin per 100 parts of epoxy resin
It is preferable to mix it in an amount of from 120 parts, especially from 40 to 70 parts. If the amount is less than 30 parts, sufficient strength cannot be obtained and 1
If it exceeds 00 parts, unreacted phenol resin may remain and the moisture resistance may decrease.

In the present invention, in addition to the epoxy resin having two or more epoxy groups in one molecule, the cyclohexane type epoxy resin, and the naphthalene ring-containing phenol resin having two or more phenolic hydroxyl groups in one molecule, In order to further enhance the effects of the present invention, it is preferable to use a silicone-modified copolymer in combination. Examples of the silicone-modified copolymer include an alkenyl group-containing epoxy resin or a phenol resin, or an alkenyl group-containing naphthalene ring-containing epoxy resin or a naphthalene ring-containing phenol resin and the addition of SiH groups in an organohydrogenpolysiloxane. Those obtained by the reaction are preferred.

Specific examples of the alkenyl group-containing epoxy resin or phenol resin, and the alkenyl group-containing naphthalene ring-containing epoxy resin or naphthalene ring-containing phenol resin include the following.

[0032]

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The following are specific examples of the organopolysiloxane.

[0034]

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The amount of the silicone-modified copolymer is preferably in the range of 0 to 50 parts, particularly 1 to 30 parts, based on 100 parts of the total amount of the epoxy resin and the phenol resin in the composition. If it exceeds 50 parts, not only the sufficient improvement in adhesiveness cannot be expected, but also the diffusion coefficient of water of the cured product becomes large, and water may easily enter.

Next, as the inorganic filler of the fourth essential component used in the present invention, those which are usually compounded in an epoxy resin composition can be used. This inorganic filler is used to reduce the expansion coefficient of the sealing material and reduce the stress applied to the semiconductor element. Specific examples thereof include crushed and spherical fused silica and crystalline silica. In addition, alumina, silicon nitride, aluminum nitride and the like can also be used. In order to achieve both low expansion of the cured product and moldability, it is better to use a blend of spherical and crushed products, or to use only spherical products. Also,
The inorganic filler preferably has an average particle size of 5 to 20 microns. Further, it is better to use this kind of inorganic filler after surface treatment with a silane coupling agent in advance.

The amount of the inorganic filler is 10 parts per 100 parts of the total amount of the epoxy resin and the phenol resin in the composition.
0 to 1800 parts is preferable, and if it is less than 100 parts, the expansion coefficient increases, the stress applied to the semiconductor element increases, and the element characteristics may deteriorate. If it exceeds 1800 parts, the viscosity at the time of molding increases, May deteriorate.

Further, a curing accelerator is preferably added to the composition of the present invention. Examples of the curing accelerator include, for example, imidazole or a derivative thereof, a phosphine derivative, and a cycloamidine derivative. The amount of the curing accelerator is 0.001 to 100 parts of the epoxy resin.
To 5 parts, preferably 0.1 to 2 parts, more preferably 0.1 to 2 parts.
If it is less than 001 parts, it may not be possible to cure in a short time, and if it exceeds 5 parts, the curing speed may be too fast to obtain a good molded product.

In the present invention, various organic synthetic rubbers, methyl methacrylate-styrene-butadiene copolymer, styrene-styrene are used to impart flexibility and toughness to the cured product of the thermosetting resin composition of the present invention. Thermoplastic resins such as ethylene-butene-styrene copolymers and fine powders such as silicone gels and silicone rubbers can be added. Alternatively, the surface of the inorganic filler may be treated with a two-pack type silicone rubber or silicone gel. Among these, a silicone-modified copolymer and a methyl methacrylate-styrene-butadiene copolymer are particularly effective in reducing the stress of the epoxy resin.

The amount of the low stress agent used is usually 0.5 to 10%, preferably 1 to 5% of the whole thermosetting resin composition. If the amount is less than 0.5%, sufficient thermal shock resistance may not be provided, while if it is more than 10%, the mechanical strength may be reduced.

The composition of the present invention may contain, if necessary, a release agent such as carnauba wax, higher fatty acid, or synthetic wax.
Further, a silane coupling agent, antimony oxide, a phosphorus compound or the like may be blended.

The composition of the present invention can be produced by melt-kneading the above-mentioned components by a heating roll, melt-kneading by a kneader, melt-kneading by a continuous extruder, or the like. There is no particular limitation on the order of compounding the components.

The thermosetting resin composition of the present invention thus obtained comprises a DIP type, a flat pack type, a PLCC type,
It is effective for semiconductor packages such as O-type, and in this case, a molding method conventionally used, for example, transfer molding,
Injection molding, casting and the like can be employed. In addition, the molding temperature of the thermosetting resin composition of this invention is 150-180 degreeC, and post cure is 150-185.
C. for 2 to 16 hours.

[0044]

As described above, the thermosetting resin composition of the present invention comprises a non-cyclohexane type epoxy resin having two or more epoxy groups per molecule, a cyclohexane type epoxy resin having two or more epoxy groups per molecule, and two per group. By using a phenolic resin having a phenolic hydroxyl group as a main component, a cured product having low hygroscopicity, low linear expansion coefficient, and high adhesiveness is provided while maintaining a high glass transition temperature. It is preferably used as

[0045]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, all parts are parts by weight.

Examples and Comparative Examples In addition to the components shown in Table 1, 600 parts of spherical silica, 10 parts of antimony trioxide, γ
-Glycidoxypropyltrimethoxysilane 1.5 parts,
A mixture obtained by adding 1.5 parts of wax E, 1.0 part of carbon black, and 0.75 part of triphenylphosphine is uniformly melt-kneaded with a hot two-roll mill to obtain eight kinds of thermosetting resin compositions. (Examples 1 to 5, Comparative Examples 1 to 5)
3).

The following various properties (a) to (e) were measured for these thermosetting resin compositions. Table 1 shows the results. (A) Spiral flow Using a mold conforming to the EMMI standard, 175 ° C, 70
It was measured under the condition of kg / cm ² . (B) Mechanical strength (flexural strength, flexural modulus) 175 ° C, 70 kg / c according to JIS K6911
A bending rod of 10 × 100 × 4 mm was molded under the conditions of m ² and molding time of 2 minutes, and post-curing was performed at 180 ° C. for 4 hours. (C) Glass transition temperature, expansion coefficient 175 ° C, 70 kg / cm ² , molding time 2 minutes
A test piece of × 4 × 15 mm was molded and post-cured at 180 ° C. for 4 hours, and the temperature was measured at 5 ° C./min by a dilatometer. (D) Moisture absorption, solder cracking and moisture resistance after moisture absorption A semiconductor device for moisture resistance testing for measuring aluminum wiring corrosion at 175 ° C., 70 kg / cm ² , and a molding time of 2 minutes is packaged in a flat package having a thickness of 2 mm. It was sealed and post-cured at 180 ° C. for 4 hours. 85 ° C /
After being left to stand in an atmosphere of 85% RH for 72 hours to perform a moisture absorption treatment, the amount of moisture absorption was measured, and this was placed in a 260 ° C. solder bath for 10 hours.
Dipped for 2 seconds. After confirming the number of cracks generated in the package at this time, only non-defective products were left in a saturated steam atmosphere at 120 ° C. for a predetermined time, and the defect occurrence rate was examined. (E) Adhesiveness A cylindrical product having a diameter of 15 mm and a height of 5 mm was molded on a 42 alloy plate under the conditions of 175 ° C., 70 kg / cm ² , and a molding time of 2 minutes, and post-cured at 180 ° C. for 4 hours.
After leaving for 16 hours at 1 ° C. and 2.1 atm, 215
It was immersed for 1 minute in the vapor phase reflow at ℃. Then, the adhesive strength with 42 alloy was investigated by tensile strength.

[0048]

[Table 1] *: The following were used as epoxy resin and phenol resin.

[0049]

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[0050]

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From the results shown in Table 1, it can be seen that the thermosetting resin composition of the present invention has a low fluidity, a low coefficient of expansion, a high glass transition temperature, and a cured product having good adhesion and low hygroscopicity. I understood.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H01L 23/31 (72) Inventor Takayuki Aoki 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture 10 Shin-Etsu Chemical Inside the Silicone Electronic Materials Research Laboratory, Industrial Co., Ltd. (72) Koji Nitsumori 1-10, Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture, Japan Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (56) References JP4 −164917 (JP, A)

Claims (2)

(57) [Claims] (A) a mixture of 20 to 95 parts by weight of a non-cyclohexane type epoxy resin having two or more epoxy groups in one molecule and 5 to 80 parts by weight of a cyclohexane type epoxy resin represented by the following formula (1): Mixed epoxy resin, (B) a phenolic resin having two or more phenolic hydroxyl groups in one molecule and having a naphthalene ring;
(C) A thermosetting resin composition comprising an inorganic filler. 2. A semiconductor device sealed with a cured product of the thermosetting resin composition according to claim 1.