JPH11293088A - Epoxy resin composition for semiconductor encapsulation and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having good resistance to solders and excellent in hardenability, low warpage properties and moldability by mixing as essential ingredients a stilbene type epoxy resin and/or a triphenolmethane type epoxy resin, a phenol/benzaldehyde resin, a hardening accelerator and an inorganic filler. SOLUTION: The titled composition comprises the components (A)-(D) below as essential ingredients: (A) a stilbene type epoxy resin represented by formula I wherein R1 -R8 are the same or different from one another and each represent H, methyl or tert-butyl, and/or a triphenolmethane type epoxy resin represented by formula II wherein k is the same or different and is 0, 1 or 2; m>=1; and R9 -R11 are the same or different from one another and each represent 1-6C linear or cyclic alkyl; (B) a phenol/benzaldehyde resin of formula III (wherein n>=1); (C) a hardening accelerator and (D) at least 73 wt.%, based on the total wt. of the epoxy resin composition, of an inorganic filler.

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 for semiconductor encapsulation having excellent solder resistance, curability, low warpage, and moldability, and a semiconductor device using the same.

[0002]

2. Description of the Related Art Epoxy resin compositions (hereinafter referred to as resin compositions) have been conventionally developed and produced in order to protect semiconductors from mechanical and chemical actions. Items required for this resin composition are changing depending on the type of semiconductor, the type of semiconductor device to be sealed, the environment in which it is used, and the like. First, various semiconductor manufacturers have proposed various small and thin semiconductor devices. For example, TSOP, TQF
And a chip scale package (CSP) such as a ball grid array (hereinafter, referred to as BGA), a small outline non-lead (SON), and the like. Almost all of these semiconductor devices are in the form of surface mount semiconductor devices. That is, it is known that there is a step in which the semiconductor device is heated to the temperature of the soldering process, and that the semiconductor device in a moisture-absorbed state easily causes popcorn cracks. In order to solve this problem, a resin composition having a low water absorption has been required. Further, in a semiconductor device having a special structure such as a BGA in which a semiconductor chip is bonded to a substrate surface and sealed with a resin composition,
It is necessary to improve the warpage of the semiconductor device. And
Improvements in resin systems are being considered to satisfy the above requirements, but most of resin systems that can satisfy the above requirements (for example,
Many phenol aralkyl resins) are inferior in moldability, especially curability. This problem is acute in a semiconductor device that needs to be mass-produced to reduce the price, and a resin system that can solve the problem has been demanded.

[0003]

SUMMARY OF THE INVENTION The present invention provides an epoxy resin composition for semiconductor encapsulation having good solder resistance, excellent curability, low warpage, and excellent moldability, and a semiconductor device using the same. Is what you do.

[0004]

The present invention provides (A) a stilbene type epoxy resin represented by the general formula (1) and / or a triphenolmethane type epoxy resin represented by the general formula (2); Phenol represented by the general formula (3)
Benzaldehyde resin, (C) curing accelerator, and (D)
An epoxy resin composition for semiconductor encapsulation comprising, as an essential component, an inorganic filler contained in the entire epoxy resin composition in an amount of 73% by weight or more, and a semiconductor device encapsulated using the same. .

Embedded image (In the formula, R _{1 to} R ₈ represent a hydrogen atom, a methyl group, or a tertiary butyl group, and may be the same or different.)

[0005]

Embedded image (In the formula, k represents 0, 1 or 2, and may be the same or different. M ≧ 1. R _{9 to} R _9
11 represents a chain or cyclic alkyl group having 1 to 6 carbon atoms, which may be the same or different from each other. )

[0006]

Embedded image (Where n ≧ 1)

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The general formula (1) used in the present invention
R _{1 to} R ₈ of the stilbene-type epoxy resin represented by represent a hydrogen atom, a methyl group, or a tertiary butyl group, and may be the same or different. These stilbene-type epoxy resins have various structures depending on the type of the substituent and the like, and may have a single structure or a mixture of two or more structures. These stilbene-type epoxy resins have a low viscosity, so that the amount of the inorganic filler can be increased, and a rigid structure, so that the curing shrinkage of the resin composition using the same can be reduced.
This is effective in reducing the warpage in A. In the triphenolmethane epoxy resin represented by the general formula (2) used in the present invention, k represents 0, 1 or 2, and may be the same or different. The substituents R _{9 to} R ₁₁ represent a chain or cyclic alkyl group having 1 to 6 carbon atoms, and may be the same or different.
Examples of the chain or cyclic alkyl group having 1 to 6 carbon atoms include a methyl group and a tertiary butyl group.
These triphenolmethane-type epoxy resins have various structures depending on the type of the substituent and the like, and may have one type or a mixture of two or more types. The use of these triphenolmethane-type epoxy resins makes it possible to increase the glass transition temperature (Tg) of the cured product of the resin composition and reduce the curing shrinkage, which is effective in reducing the warpage in BGA. The melting point, softening point, melt viscosity, content of ionic impurities and the like of the above-mentioned epoxy resin are not particularly limited, but the lower the content of ionic impurities, the better the reliability and the better.

The above two types of epoxy resins may be used in combination with each other, and there is no problem when used in combination with another epoxy resin. As the epoxy resin used in combination, for example, bisphenol A type epoxy resin, brominated epoxy resin, bisphenol F type epoxy resin, hydroquinone type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, and dicyclopentadiene modified phenol type Epoxy resins and the like may be mentioned, and these may be used alone or as a mixture.

The phenol / benzaldehyde resin represented by the general formula (3) used in the present invention is a co-condensation product of phenol and benzaldehyde. Since the shrinkage ratio can be reduced, it is effective in reducing the warpage in the BGA, and is also effective in reducing the water absorption ratio, and the solder resistance is improved. The softening point, melt viscosity, content of ionic impurities, and the like are not particularly limited, but those having a lower content of ionic impurities have higher reliability and are preferred. or,
The phenol / benzaldehyde resin of the present invention may be used in combination with another phenol resin curing agent as long as the properties of the phenol / benzaldehyde resin are not impaired. Examples of the phenol resin curing agent used in combination include, for example, phenol novolak resin, orthocresol novolak resin, phenol aralkyl resin, dicyclopentadiene-modified phenol resin, limonene-modified phenol novolak resin, triphenolmethane-type phenol resin, and the like. They may be used alone or as a mixture. The equivalent ratio of the epoxy group of all epoxy resins used in the present invention to the phenolic hydroxyl group of all phenolic resins is preferably 0.5 to 2, and more preferably 0.7 to 1.5. If the ratio is out of the range of 0.5 to 2, the moisture resistance, the curability and the like are undesirably reduced.

The curing accelerator used in the present invention is not particularly limited as long as it accelerates the reaction between the epoxy group and the phenolic hydroxyl group. For example, 1,8-diazabicyclo (5,4,0) undecene- 7, triphenylphosphine, tetraphenylphosphonium / tetraphenylborate, tetraphenylphosphonium / tetrabenzoic acid borate, tetraphenylphosphonium / tetranaphthoic acid borate, etc., and these may be used alone or in combination.

The kind of the inorganic filler used in the present invention is not particularly limited, and those generally used for a sealing material can be used. For example, fused crushed silica powder, fused spherical silica powder, crystalline silica powder, secondary aggregated silica powder, alumina, titanium white, aluminum hydroxide, talc, clay, glass fibers, and the like,
Particularly, a fused spherical silica powder is preferable. The shape is preferably infinitely spherical, and the filling amount can be increased by mixing particles having different particle sizes. The content of the inorganic filler is 73% in the total resin composition.
% By weight or more is preferred. If the content is less than 73% by weight, a resin composition having a large coefficient of thermal expansion is obtained, and the warpage of the BGA becomes large.

The resin composition of the present invention comprises, in addition to the components (A) to (D), a silane coupling agent such as γ-glycidoxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane, if necessary. Colorants such as carbon black, brominated epoxy resins, antimony oxide, flame retardants such as phosphorus compounds, low-stress components such as silicone oil and silicone rubber, natural wax, synthetic wax, polyethylene wax, polyethylene oxide wax, higher fatty acids and the like. Various additives such as a release agent such as metal salts or paraffin, and an antioxidant can be blended. In particular, silicone oil and silicone rubber having low stress components are effective in reducing warpage. The resin composition of the present invention comprises (A)
(D) The component and other additives are mixed at room temperature using a mixer, kneaded with a kneader such as a roll or an extruder, cooled, and pulverized. In order to manufacture a semiconductor device by encapsulating various packages such as semiconductors using the resin composition of the present invention, it is sufficient to cure and mold by a conventional molding method such as transfer molding, compression molding and injection molding.

[0013]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. The mixing unit is parts by weight. Example 1 3.6 parts by weight of epoxy resin of formula (E-1) 5.5 parts by weight of epoxy resin of formula (E-2)

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6.2 parts by weight of a phenolic resin of the formula (H-1)

Embedded image 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 0.2 part by weight Fused spherical silica (average particle size 15 μm) 82.2 parts by weight Epoxysilane coupling agent 0.5 part by weight Carbon black 0.5 part by weight Brominated bisphenol A type epoxy resin 0.5 part by weight Antimony trioxide 0.5 part by weight Carnauba wax 0.3 part by weight is mixed at room temperature using a mixer and then biaxially at 100 ° C. The mixture was kneaded using a roll, cooled and pulverized to obtain a resin composition. The obtained resin composition was evaluated by the following method. Table 1 shows the results.

Evaluation method Curability: Using a low pressure transfer molding machine, molding temperature 1
75 ° C., pressure 70 kg / cm ² , curing time 2 minutes, 25
6pBGA (bismaleimide triazine resin / glass cloth substrate, size 27 mm × 27 mm, IC chip size 9 mm × 9 mm) was molded, and the Bacol hardness immediately after molding (10 seconds after the mold was opened) was measured. Releasability: In the molding of BGA, the state of release was evaluated by ○ and ×. The curing time including the injection time was 60 seconds. BGA warpage: 256 pBGA (bismaleimide triazine resin / glass cloth substrate, size 27 mm × 27 mm, IC: 175 ° C., pressure 70 kg / cm ² , curing time 2 minutes, using a low-pressure transfer molding machine)
(Chip size 9mm x 9mm), 175 ℃, 8
After post-curing for a time, the amount of warpage of the BGA was measured using a surface roughness meter (Surfcom, manufactured by Tokyo Seimitsu Co., Ltd.). The amount of warpage of the BGA indicates a value of the maximum amount of warpage obtained by measuring the diagonal direction of the BGA using a surface roughness meter. The unit is μm. Solder resistance: Using a low-pressure transfer molding machine, a molding temperature of 175 ° C., a pressure of 70 kg / cm ² , and a curing time of 2 minutes, 2
After molding 56pBGA (bismaleimide / triazine resin / glass cloth substrate, size 27 mm × 27 mm, IC chip size 9 mm × 9 mm), post-curing at 175 ° C. for 8 hours, 96 ° C. at 85 ° C. and 60% relative humidity. Time treatment, IR reflow treatment (220 ° C,
10 seconds). The treated BGA was observed using an ultrasonic flaw detector, and internal peeling and cracks were observed. The number of defective BGAs out of the six BGAs is shown.

Examples 2 to 12 Compounded according to the formulation shown in Table 1, a resin composition was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 1 shows the results. Comparative Examples 1-3 Compounded according to the formulation in Table 2, a resin composition was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 2 shows the results. The epoxy resins used in Examples 2 to 12 and Comparative Examples 1 to 3 are represented by Formulas (E-3) to (E-7), and the phenol resin curing agents are represented by Formulas (H-2) to (H-5). Shown in The curing accelerator used in Examples 4 to 6 and 9 to 12 was triphenylphosphine, and the curing accelerator used in Examples 8 and 10 was tetraphenylphosphonium tetranaphthoic acid borate (hereinafter, referred to as TPPK-NA). is there.

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[0017]

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[0018]

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[0019]

[Table 1]

[0020]

[Table 2]

[0021]

The epoxy resin composition for semiconductor encapsulation of the present invention is excellent in solder resistance, curability, low warpage, and moldability, and is used for surface mounting semiconductor devices, particularly BG.
The productivity and reliability of A are improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 23/31

Claims (2)

[Claims] 1. A stilbene type epoxy resin represented by the general formula (1) and / or a triphenolmethane type epoxy resin represented by the general formula (2), and (B) a general formula (3) Phenol / benzaldehyde resin,
An epoxy resin composition for semiconductor encapsulation comprising, as essential components, (C) a curing accelerator and (D) an inorganic filler contained in an amount of 73% by weight or more in the total epoxy resin composition. Embedded image (In the formula, R _{1 to} R ₈ represent a hydrogen atom, a methyl group, or a tertiary butyl group, and may be the same or different from each other.) (In the formula, k represents 0, 1 or 2, and may be the same or different. M ≧ 1. R _{9 to} R _9
11 represents a chain or cyclic alkyl group having 1 to 6 carbon atoms, which may be the same or different from each other. ) (Where n ≧ 1) 2. A semiconductor device which is encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.