JP2643706B2 - 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.

As a solution to the above problem, a biphenyl type epoxy resin is frequently used as an epoxy resin. However, since this epoxy resin has a low degree of polymerization, the glass transition temperature of the cured product becomes 150 ° C. or less. As a result, it is insufficient as a material for sealing a semiconductor element.

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

[0006]

The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that a thermosetting resin composition containing an epoxy resin, a phenolic resin, a curing agent, and the like has an epoxy resin. A fluorene-type epoxy resin represented by the following formula (1), a naphthalene ring-containing epoxy resin represented by the following formula (4), and a dicyclopentadiene-modified phenol resin represented by the following general formula (2) as a phenol resin. It has good fluidity, low expansion coefficient, high glass transition temperature, excellent adhesiveness, and gives a cured product with low hygroscopicity, and is further sealed with a cured product of this thermosetting resin composition. The inventors have found that the stopped semiconductor device has high reliability, and have accomplished the present invention.

[0007]

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Accordingly, the present invention provides an epoxy resin containing a fluorene type epoxy resin represented by the following formula (1) and a naphthalene ring-containing epoxy resin represented by the following formula (4): And a dicyclopentadiene-modified phenol resin as an essential component, the compounding amount of the fluorene type epoxy resin is 5% by weight or more of the entire epoxy resin, and the compounding amount of the naphthalene ring-containing epoxy resin is such that the naphthalene ring content is Provided is a thermosetting resin composition, which is in an amount of 5 to 80% by weight of the entire epoxy resin, and a semiconductor device sealed with a cured product of the composition.

[0009]

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Hereinafter, the present invention will be described in more detail. The first essential component of the thermosetting resin composition of the present invention is represented by the following formula (1) and a fluorene epoxy resin represented by the following formula (4). It is a naphthalene ring-containing epoxy resin.

[0011]

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The compounding amount of the fluorene type epoxy resin of the above formula (1) is preferably at least 5% (% by weight, hereinafter the same) of the total epoxy resin in the composition, particularly preferably at least 10%. If the amount is less than 5%, sufficient adhesiveness may not be obtained.

In the present invention, another epoxy resin may be blended in addition to the above epoxy resin. As other epoxy resins, for example, an epoxy resin having at least two epoxy groups in one molecule is preferable,
Specifically, bisphenol A type epoxy resin, phenol novolak type epoxy resin, triphenol alkane type epoxy resin and its polymer, biphenyl type epoxy resin, dicyclopentadiene-phenol novolak resin, phenol aralkyl type epoxy resin, glycidyl ester type epoxy Examples thereof include resins, alicyclic epoxy resins, heterocyclic epoxy resins, brominated epoxy resins, and bishydroxybiphenyl-based epoxy resins.

[0014]

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The epoxidized α-naphthol or α, β-naphthol in the above naphthalene ring-containing epoxy resin is preferably 10% by weight or less, and more preferably 7% by weight or less from the viewpoint of heat resistance and moisture resistance. It is. In addition to this, the content of a binuclear substance composed of only phenol or phenylglycidyl ether is preferably 0.5% by weight or less, particularly preferably 0.2% by weight 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 the naphthalene ring-containing epoxy resin include the following compounds.

[0019]

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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% by weight, particularly 10 to 60% by weight. It is preferable to adjust the amount of the naphthalene ring-containing epoxy resin so that the naphthalene ring content falls within this range.

Next, the dicyclopentadiene-modified phenol resin of the second component acts as a curing agent for the epoxy resin of the first component, and is represented by the following general formula (2).

[0022]

Embedded image (In the formula, R ¹ is an alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group, and n is an integer of 0 to 15.)

Specific examples of the phenolic resin represented by the general formula (2) include the following compounds.

[0024]

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The compounding amount of the dicyclopentadiene-modified phenol resin of the above formula (2) is preferably 20 to 100%, particularly preferably 40 to 100% of the whole phenol resin in the composition. If the amount is less than 20%, sufficient adhesiveness may not be obtained, and the moisture resistance may be reduced.

In the thermosetting resin composition of the present invention,
Although the above-mentioned dicyclopentadiene-modified phenol resin is used as an essential component as the phenol resin, other ordinary phenol resins can be used in combination. As a typical example of such a phenol resin, a phenol resin having at least two phenolic hydroxyl groups in one molecule is preferable. Specific examples include phenol resins such as novolak type phenol resins, resol type phenol resins, phenol aralkyl resins, triphenol alkane type resins and polymers thereof, and naphthalene ring-containing phenol resins. In particular, by using a naphthalene ring-containing phenol resin in combination, a thermosetting resin composition having low moisture absorption and excellent adhesion can be obtained. Further, it may be used in combination with an amine curing agent or an acid anhydride curing agent.

Among these phenolic resins, it is preferable to combine a naphthalene ring-containing phenolic resin represented by the following general formula (3) and a dicyclopentadiene-modified phenolic resin, whereby the water absorption rate is remarkably reduced and the adhesive strength is improved. Combined with low moisture absorption, exhibiting excellent resistance to cracking during solder immersion after moisture absorption.

[0028]

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Specific examples of these phenol resins include the following.

[0030]

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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.
~ 130 ° C. The hydroxyl equivalent is 90-2.
50 are preferred. When this phenol resin is used for semiconductor encapsulation, sodium and potassium are 10 ppm.
It is preferable that sodium and potassium are 1 or less.
When a semiconductor device is sealed with a resin exceeding 0 ppm and the semiconductor device is left for a long time under high temperature and high humidity, deterioration of moisture resistance may be promoted.

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,
Usually, it is preferable to mix 30 to 100 parts, especially 40 to 70 parts of a phenol resin with respect to 100 parts (parts by weight, hereinafter the same) of the epoxy resin. If the amount is less than 30 parts, sufficient strength may not be obtained, and if it exceeds 100 parts, unreacted phenol resin may remain and moisture resistance may decrease.

In the present invention, it is preferable to use a silicone-modified copolymer in addition to the fluorene-type epoxy resin and the dicyclopentadiene-modified phenol resin in order to further enhance the effect of the present invention. 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, the alkenyl group-containing naphthalene ring-containing epoxy resin or the naphthalene ring-containing phenol resin include the following.

[0035]

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The following are specific examples of the organopolysiloxane.

[0037]

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The amount of the silicone-modified copolymer is preferably in the range of 0 to 50 parts, more preferably 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, in the present invention, an inorganic filler can be used. These inorganic fillers are 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. Furthermore,
This kind of inorganic filler is preferably used 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, it is preferable to add a curing accelerator 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 use of these low stress agents is usually 0.5 to 10% by weight, particularly preferably 1 to 5% by weight, based on the whole thermosetting resin composition. If the amount is less than 0.5% by weight, sufficient thermal shock resistance may not be provided.
If it is larger, the mechanical strength may decrease.

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 with a heating roll, melt-kneading with a kneader, or melt-kneading with a continuous extruder. There is no particular limitation on the order of compounding the components.

The thermosetting resin composition of the present invention thus obtained comprises DIP type, flat pack type, 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.

[0047]

As described above, the thermosetting resin composition of the present invention comprises a fluorene-type epoxy resin and a dicyclopentadiene-modified phenol resin as essential components, thereby maintaining a high glass transition temperature while maintaining a low glass transition temperature. It gives a cured product having hygroscopicity and high adhesiveness, and is suitably used for semiconductor packages.

[0048]

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, 550 parts of spherical silica, 10 parts of antimony trioxide, 1.5 parts of γ-glycidoxypropyltrimethoxysilane, 1.5 parts of wax E, carbon The mixture obtained by adding 1.0 part of black and 0.8 part of triphenylphosphine was uniformly melt-kneaded with a hot two-roll mill to produce four types of thermosetting resin compositions. ,
2, Comparative Examples 1 and 2).

The following various properties (a) to (e) of these thermosetting resin compositions were measured. 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.

[0051]

[Table 1]

[0052]

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[0053]

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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 expansion coefficient, a high glass transition temperature, and a cured product having good adhesiveness and low hygroscopicity. I understood.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takayuki Aoki 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Inside the Silicone Electronics Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (56) References JP-A-1-105562 ( JP, A) JP-A-1-268713 (JP, A) JP-A-62-201922 (JP, A) JP-A-62-201923 (JP, A) JP-A-62-96521 (JP, A) Hei 2-73823 (JP, A)

Claims (3)

(57) [Claims] An epoxy resin containing a fluorene type epoxy resin represented by the following formula (1) and a naphthalene ring-containing epoxy resin represented by the following formula (4), and a dicyclopentadiene represented by the following general formula (2) A modified phenol resin as an essential component, the compounding amount of the fluorene-type epoxy resin is 5% by weight or more of the entire epoxy resin, and the compounding amount of the naphthalene ring-containing epoxy resin is such that the naphthalene ring content of the entire epoxy resin is A thermosetting resin composition having an amount of 5 to 80% by weight. Embedded image 2. The thermosetting resin composition according to claim 1, further comprising a naphthalene ring-containing phenol resin represented by the following general formula (3). Embedded image (Where R ¹ is an alkyl group having 1 to 10 carbon atoms, A is a hydroxyl group, B is a hydroxyl group or a hydrogen atom, k is an integer of 0 to 5,
1 represents an integer of 0 to 3, m represents an integer of 0 to 2, and p represents 1 or 2. A may be added to either ring of the naphthalene ring or may be added to both rings simultaneously. ) 3. A semiconductor device sealed with a cured product of the thermosetting resin composition according to claim 1.