JP2701695B2 - Epoxy 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 an epoxy resin composition having a low hygroscopic property and providing a cured product having excellent adhesion to a frame and excellent solder crack resistance, and a semiconductor device sealed with the composition. .

[0002]

2. Description of the Related Art
In the semiconductor industry, resin-sealed type diodes, transistors, ICs, LSIs, and ultra-LSIs are the mainstream, and epoxy resin is generally more moldable and adhesive than other thermosetting resins. Because of their excellent electrical properties, mechanical properties, moisture resistance, etc., semiconductor devices are often sealed with epoxy resin compositions.

In recent years, the degree of integration of these semiconductor devices has been increasing, and the chip size has been increasing accordingly. On the other hand, package external dimensions have been reduced in size and thickness in accordance with demands 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.

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 melts. 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 after mounting may be greatly impaired.

[0005] The present invention has been made in view of the above circumstances,
An epoxy resin composition which is excellent in low moisture absorption, can prevent peeling of an interface between a frame or a chip and a sealing resin, and gives a cured product having good crack resistance, and a cured product of the composition. It is an object to provide a sealed semiconductor device.

[0006]

The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that an epoxy resin composition containing an epoxy resin, a curing agent and an inorganic filler as essential components has the following features. By adding the silane coupling agent represented by the general formula (1), the adhesion between the frame or chip and the resin and the reinforcement of the interface between the filler and the resin can be greatly improved. The inventors have found that the water absorption of a cured product can be made lower than that of a conventional product, and have accomplished the present invention.

[0007]

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Accordingly, the present invention provides an epoxy resin composition,
An epoxy resin composition comprising an epoxy resin composition containing a curing agent and an inorganic filler as essential components, and a silane coupling agent represented by the above general formula (1), and an epoxy resin composition comprising: Provided is a semiconductor device sealed with a cured product.

Hereinafter, the present invention will be described in more detail. As the epoxy resin constituting the epoxy resin composition of the present invention,
Any epoxy resin having at least two epoxy groups in one molecule may be used. Specifically, bisphenol A type epoxy resin, phenol novolak type epoxy resin, triphenol alkane type epoxy resin and a polymer thereof, Use biphenyl type epoxy resin, dicyclopentadiene-phenol novolak resin, phenol aralkyl type epoxy resin, naphthalene ring-containing epoxy resin, glycidyl ester type epoxy resin, alicyclic epoxy resin, heterocyclic type epoxy resin, brominated epoxy resin, etc. be able to. Among these epoxy resins, a naphthalene ring-containing epoxy resin or a biphenyl type epoxy resin represented by the following formula is preferable in terms of obtaining low moisture absorption and high adhesiveness.

[0010]

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Specific examples of the naphthalene ring-containing epoxy resin and biphenyl type epoxy resin include the following compounds.

[0012]

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Here, the epoxidized α-naphthol or α, β-naphthol in the above naphthalene ring-containing epoxy resin is desirably not more than 10% (% by weight, the same applies hereinafter), and particularly, heat resistance and moisture resistance. More preferably, it is 7% or less from the surface. 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 above epoxy resin has a softening point of 50 to 50.
Those having an epoxy equivalent of 100 to 400 at 120C are preferred. When an epoxy resin having a softening point lower than 50 ° C. is used, not only does the glass transition temperature of the cured product decrease, but burrs and voids are easily generated at the time of molding, and when the softening point is higher than 120 ° C., the viscosity is low. It may be too high to be molded. In this case, the softening point of the naphthalene ring-containing epoxy resin is affected by the epoxidized content of α-naphthol and α, β-naphthol in the naphthalene ring-containing epoxy resin.
It is preferable that the content of the epoxide of naphthol be 10% or less and the softening point be 50 to 120 ° C, particularly 70 to 110 ° C.

When the epoxy resin is used for encapsulating a semiconductor, the content of hydrolyzable chlorine is preferably 1000 ppm or less, particularly 500 ppm or less, and sodium and potassium are each preferably 10 ppm or less. If a semiconductor device is sealed with a resin in which hydrolyzable chlorine exceeds 1000 ppm and sodium and potassium exceed 10 ppm, and the semiconductor device is left under high temperature and high humidity for a long time, moisture resistance may be deteriorated.

Next, as a curing agent for the epoxy resin, 1
Phenolic resins having at least two phenolic hydroxyl groups in the molecule are preferred. Specific examples of such a curing agent include a novolak type phenol resin, a resol type phenol resin, a phenol aralkyl resin, a phenol resin such as a triphenol alkane type resin and a polymer thereof, a naphthalene ring-containing phenol resin, and a dicyclopentadiene-modified phenol. Examples of the resin include a phenol resin represented by the following formula.

[0017]

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In this case, the use of the above naphthalene ring-containing phenol resin makes it possible to obtain an epoxy resin composition having low moisture absorption and excellent adhesion. Further, an amine-based curing agent or an acid anhydride-based curing agent may be used in combination with the phenol resin.

These curing agents have a softening point of 60 to 60.
Those having a temperature of 150 ° C, particularly 70 to 130 ° C, are preferred.
Moreover, the thing of 90-250 is preferable as a hydroxyl equivalent. Further, when such a phenolic resin is used for semiconductor encapsulation, sodium and potassium are preferably set to 10 ppm or less, and the semiconductor device is sealed at more than 10 ppm, and the semiconductor device is left under high temperature and high humidity for a long time. In this case, the deterioration of the moisture resistance may be promoted.

Although the amount of the curing agent is not particularly limited, when the above-mentioned phenol resin is used, the molar ratio of the epoxy group in the epoxy resin to the phenolic hydroxyl group in the curing agent is 0.5 to 1.5. Range, especially 0.8 to 1.2
It is preferable to set it in the range.

As the inorganic filler, those usually blended in an epoxy resin composition can be used. This inorganic filler is compounded to reduce the expansion coefficient of the sealing material and reduce the stress applied to the semiconductor element. Specifically, fused silica and crystalline silica having a crushed or spherical shape are mainly used. In addition, alumina, silicon nitride, aluminum nitride and the like can be used.

The average particle size of these inorganic fillers is as follows:
It is preferably 5 to 20 microns, and the filling amount is 100 to 100 parts based on the total amount of the epoxy resin and the curing agent of 100 parts.
It is preferably 1800 parts, particularly preferably 500 to 900 parts. If the filling amount is less than 100 parts, the expansion coefficient increases and the stress applied to the semiconductor element increases, which may lead to deterioration of the element characteristics. If the filling amount exceeds 1800 parts, the viscosity at the time of molding increases and the moldability deteriorates. There are cases.

It is recommended to use a blend of a sphere and a crushed product, or to use only a sphere in order to achieve both a low expansion of the cured product and moldability. In addition, it is preferable that the above-mentioned inorganic filler is surface-treated with a silane coupling agent before use.

The epoxy resin composition of the present invention is obtained by mixing a silane coupling agent represented by the following general formula (1) with a composition containing the above-described epoxy resin, a curing agent and an inorganic filler.

[0025]

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Specific examples of the silane coupling agent include compounds represented by the following structural formula.

[0027]

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Since the silane coupling agent used in the present invention has a phenyl group and two functional groups in the molecule, it has good compatibility with epoxy resins and phenol resins, and has good dispersibility in a matrix. Can be improved. On the other hand, a strong bond with the epoxy resin can be formed at the interface between the filler and the resin, and also on the surface of the frame or chip due to the good compatibility. Further, in order to further exert this effect, it is desirable to previously treat the surface of the above-mentioned inorganic filler with these silane coupling agents. In this case, the silane coupling agent may treat the surface of the inorganic filler alone or in combination with another coupling agent. During the surface treatment, the coupling agent is hardly dissolved in water, and the reactivity of a hydrolyzing group such as an alkoxy group is very poor.
It may be dissolved in a mixture of alcohol and water, a partially hydrolyzed solution may be used in advance, or a catalyst that promotes hydrolysis may be added. As such a catalyst, for example, those used as condensation catalysts for silicone such as nitrogen-containing compounds, tin-containing compounds, and titanium-containing compounds can be used.

The amount of the silane coupling agent used is preferably 0.1 to 10 parts, more preferably 0.5 to 5 parts, per 100 parts of the total amount of the epoxy resin and the phenol resin. If the amount is less than 0.1 part, the effect is not sufficiently exhibited. If the amount is more than 10 parts, the glass transition temperature of the cured product is lowered, and the mechanical strength may be reduced.

Incidentally, in addition to such a coupling agent, a conventionally known silane coupling agent or titanium-based coupling agent may be used in combination.

[0031] In addition to the above components, a curing accelerator can be added to the composition of the present invention. Examples of the curing accelerator include imidazole or a derivative thereof, a phosphine derivative, a cycloamidine derivative, and the like. The compounding amount was 0.001 to 100 parts of the epoxy resin.
To 5 parts, particularly preferably 0.1 to 2 parts. 0.
If it is less than 001 parts, it cannot be cured in a short time, and
If the amount exceeds the above range, the curing rate may be too high to obtain a good molded product.

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

The amount of the thermoplastic resin used as the above-mentioned low-stress agent is usually 0.5 to 1% of the entire epoxy resin composition.
It is preferably 0%, particularly preferably 1 to 5%. If the amount is less than 0.5%, sufficient thermal shock resistance may not be imparted. On the other hand, if the amount exceeds 10%,
Mechanical strength may decrease.

The composition of the present invention may further contain, if necessary, a release agent such as carnauba wax, higher fatty acid, or synthetic wax, as well as antimony oxide and a phosphorus compound.

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

The epoxy resin composition of the present invention thus obtained is a DIP type, flat pack type, PLCC type,
It is effective for a semiconductor package such as an O-type package, and in this case, it can be performed by a conventionally employed molding method, for example, transfer molding, injection molding, casting method and the like. The molding temperature of the epoxy resin composition of the present invention is 150 to 180 ° C, and the post cure is 150 to 185.
C. for 2 to 16 hours.

[0037]

The epoxy resin composition of the present invention can provide a cured product having low moisture absorption, excellent adhesion to a frame or a chip, and good solder cracking resistance. The manufactured semiconductor device has high reliability.

[0038]

EXAMPLES Hereinafter, the present invention will be described 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 1 to 5, Comparative Examples 1 and 2 550 parts of spherical silica and antimony trioxide 10 were added to the components shown in Table 1.
Parts, 1.5 parts of wax E, 1.0 part of carbon black,
0.8 parts of triphenylphosphine was added, and the resulting mixture was uniformly melt-kneaded with a hot two-roll mill to produce seven types of thermosetting resin compositions. The following various properties (a) to (e) were evaluated for the obtained epoxy resin composition.
The results are also shown in Table 1. (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) Thermal breaking strength (total absorbed energy) 7 at 175 ° C., 70 kg / cm ² , and 2 minutes molding time
A disk of 0φ × 2 mm was formed, post-cured at 180 ° C. for 4 hours, and placed in a 120 ° C. pressure cooker.
After leaving for a while, the impact tester (Toyo Seiki Co., Ltd.)
Was used at 170 ° C. to measure the total absorbed energy. (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 passed through an infrared reflow furnace. After confirming the number of cracks generated in the package at this time, only non-defective products were allowed to stand in a saturated steam atmosphere at 120 ° C. for a predetermined time, and the defect occurrence rate was examined. (E) Adhesiveness A cylindrical molded 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.

[0040]

[Table 1]

[0041]

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From the results shown in Table 1, the epoxy resin composition containing the silane coupling agent according to the present invention (Example)
Has better moisture absorption, better adhesiveness, better crack resistance and better moisture resistance than those with conventional silane coupling agent or without silane coupling agent (Comparative Example) It was confirmed to give goods.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location H01L 23/31 C07F 7/18 S // C07F 7/18 H01L 23/30 R (72) Inventor Satoshi Okuse 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd.Silicon Electronic Materials Research Laboratory (72) Inventor Takayuki Aoki 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Inside Silicone Electronics Materials Research Laboratory (72) Inventor Sachi Wakao 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Inside Silicone Electronics Materials Research Laboratory (72) Inventor Shigeki Ino Matsui, Usui-gun, Gunma Prefecture Hitomi Tamachi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory (56) References Open flat 4-59862 (JP, A) JP flat 4-55424 (JP, A) JP flat 6-172370 (JP, A)

Claims (2)

(57) [Claims] 1. An epoxy resin comprising an epoxy resin composition containing an epoxy resin, a curing agent and an inorganic filler as essential components, and a silane coupling agent represented by the following general formula (1). Composition. Embedded image 2. A semiconductor device sealed with a cured product of the epoxy resin composition according to claim 1.