JPH1036486A - Epoxy resin composition for semiconductor sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for semiconductor sealing, excellent in mold release and adhesion by mixing an epoxy resin with a phenolic resin curing agent, a cure accelerator, an inorganic filler and specified waxes in a specified mixing ratio. SOLUTION: This composition comprises an epoxy resin, a phenolic resin curing agent, a cure accelerator, an inorganic filler and waxes represented by formulas I and/or II (wherein R is H, a phenyl or a 1-50C alkyl; m>=1; and 1<=n<=300). The waxes should be each a copolymer of a polystyrene with maleic anhydride and should be used in an amount of 0.02-1wt.% based on the entire composition.

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 which is excellent in releasability and adhesion.

[0002]

2. Description of the Related Art A thermosetting resin as a resin component of an epoxy resin composition for semiconductor encapsulation of a transistor, a capacitor, a diode, an IC, an LSI or the like (hereinafter referred to as a resin composition), an inorganic filler as a filler, a mold release. As the agent component, a high-molecular fatty acid, a high-molecular fatty acid ester, and other various higher aliphatic compounds are used as raw materials suitable for moldability, reliability, and mass productivity. In recent years, electronic devices have become smaller and lighter,
In the market trend of higher performance and lower price, the demand for resin compositions has become more and more severe, and short-time molding and improvement in yield have been required to improve the productivity of semiconductor devices. That is, miniaturization and thinning of the semiconductor package make molding of the resin composition at the time of encapsulation extremely difficult, and it is necessary to greatly improve releasability from a mold. In addition, due to the adoption of the surface mounting of the semiconductor device, the package is rapidly exposed to a high temperature of 200 ° C. or more in the solder immersion or reflow process, and the interface between the chip and the sealing resin is easily peeled off.
The sealing resin needs to have good adhesion to various substrates. Various waxes have been studied to achieve both the above good releasability and good adhesion. For example, Japanese Patent Publication No. Hei 7-37041 aims to achieve both release properties and adhesiveness by using oxidized polyethylene wax, but it has a sufficient effect on current thin and small packages. I couldn't.

[0003]

SUMMARY OF THE INVENTION The present invention improves the productivity by improving the releasability from a mold at the time of molding, improves the adhesion to various base materials, and improves the solder resistance. An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation having excellent reliability.

[0004]

The present invention provides an epoxy resin, a phenol resin curing agent, a curing accelerator, an inorganic filler,
An epoxy resin composition for semiconductor encapsulation, comprising a wax represented by the formula (1) and / or formula (2), wherein the wax is contained in the entire resin composition in an amount of 0.02 to 1% by weight.

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[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention refers to all polymers having an epoxy group. For example, bisphenol type epoxy resin, orthocresol novolak type epoxy resin, biphenyl type epoxy resin, phenol novolak type epoxy resin and triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, epoxy resin containing triazine nucleus, dicyclopentadiene Modified epoxy resins, stilbene type epoxy resins, and the like are included. The softening point and epoxy equivalent of the epoxy resin are not particularly limited. These epoxy resins may be used alone or as a mixture.
It is desirable that the epoxy resin used in the present invention has few ionic impurities such as chlorine ions and sodium ions in order to improve moisture resistance reliability.

[0006] The phenolic resin curing agent used in the present invention refers to all polymers having a phenolic hydroxyl group. For example, a phenol novolak resin, a cresol novolak resin, a dicyclopentadiene-modified phenol resin, a paraxylylene-modified phenol resin, a triphenolmethane-type phenol resin, and the like can be given. The melting point of the phenol resin and the hydroxyl equivalent are not particularly limited. Further, these phenol resins may be used alone or in combination. It is desirable that the phenolic resin used in the present invention has few ionic impurities such as chlorine ions and sodium ions in order to improve the moisture resistance reliability. The number of epoxy groups in the epoxy resin and the number of hydroxyl groups in the phenol resin are preferably equivalent.

The inorganic filler used in the present invention includes:
For example, a fused silica powder, a spherical fused silica powder, a crystalline silica powder, a secondary aggregated silica powder, a porous silica powder, a silica powder obtained by pulverizing a secondary aggregated silica powder or a porous silica powder, and alumina are exemplified. The shape of the inorganic filler may be crushed or spherical. Further, these inorganic fillers may be used alone or in combination. In addition, it is preferable to use spherical fused silica powder in which the flow characteristics, mechanical strength, and thermal characteristics are balanced.

The curing accelerator used in the present invention includes:
Any material that promotes the reaction between the epoxy resin and the phenolic hydroxyl group may be used, and those generally used as sealing materials can be widely used. For example, 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, tetraphenylphosphonium / tetraphenylborate, dimethylbenzylamine, tetraphenylphosphonium / tetranaphthoic acid borate and the like can be mentioned. These curing accelerators may be used alone or as a mixture. These curing accelerators may be dry-blended, melt-blended, or a combination of both in the resin.

The waxes represented by the formulas (1) and (2) used in the present invention will be described in detail below. The wax used in the present invention is a copolymer of polyalphaolefin or polystyrene and maleic anhydride. By containing the maleic anhydride of a hydrophilic group, the affinity with the epoxy resin is improved, and the resin can be dispersed well in the resin composition. By using this, mold stains during molding are almost eliminated. . In addition, the maleic anhydride moiety
It has a function of satisfactorily adhering to a hydrophilic metal surface, a polyimide-based chip coat material, and the like. It is also known that if the water or alcohol components remain as volatile components in the resin composition, they cause voids during molding, but the maleic anhydride reacts with the water and alcohol components to trap. It has also been found that the effect reduces the number of voids in the sealed semiconductor device. Next, the poly-alpha olefin or polystyrene portion, which is a hydrophobic group, has a small surface energy, so that it slightly oozes out to the surface of the molded product, which is effective in improving the releasability from the mold. Moreover, since the wax has a relatively large molecular weight, it does not easily migrate to the surface of the mold, and there is almost no stain on the mold. Furthermore, it exhibits tackiness in a high temperature range (temperature at the time of solder mounting: 200 ° C. or more), and exhibits a great effect in improving the adhesion between the sealing resin and various base materials. By blending the wax of the present invention having these features into a resin composition, it has become possible to achieve both mold release and adhesion, which could not be achieved by a conventional wax system. In the formulas (1) and (2), m is 1 or more. If it is less than 1, the releasability is reduced due to a small number of hydrophobic groups. n is 1 to 300. If it is less than 1, the molecular weight is too small, and no releasability or adhesion is exhibited. On the other hand, 30
If it exceeds 0, the melting point becomes too high and it cannot be uniformly dispersed in the resin composition. R is hydrogen, a phenyl group, or an alkyl group. In the case of an alkyl group, x is 1 to 50. If it exceeds 50, the wax will bleed out due to too strong hydrophobicity. In addition, the synthesis of wax becomes extremely difficult and is not practical. The wax of the formulas (1) and (2)
The same effect is exhibited when used alone or as a mixture.

[0010] The wax used in the present invention is desirably added to the entire resin composition in an amount of 0.02 to 1% by weight.
If it is less than 0.02% by weight, the effect of improving the releasability and adhesion is small, which is not preferable. On the other hand, if it exceeds 1% by weight, it bleeds out to the surface of the molded article, causing stains on the molded article and mold, and also lowers the adhesiveness and the solder resistance. The wax of the present invention can be used in combination with an ester wax such as carnauba wax or an acid wax such as stearic acid wax and lead stearate.

The resin composition of the present invention comprises an epoxy resin, a phenol resin curing agent, an inorganic filler, a curing accelerator, and a compound represented by the formula (1):
And / or a wax of the formula (2) as an essential component, if necessary, a silane coupling agent, a brominated epoxy resin, a flame retardant such as antimony trioxide, hexabromobenzene, and a coloring agent such as carbon black and red iron. And various additives such as low-stress additives such as silicone oil and rubber.

In order to produce the resin composition of the present invention as a molding material, epoxy resin, phenol resin curing agent, curing accelerator, inorganic filler, wax of formula (1) and / or formula (2), other After the additives are sufficiently and uniformly mixed by a mixer or the like, they are further melt-mixed by a hot roll or a kneader, cooled, and pulverized to obtain a molding material. These molding materials can be used for sealing or coating electronic or electrical components,
It can be applied to insulation and the like.

[0013]

The present invention will be described below by way of examples. The mixing ratio is by weight. Example 1 Biphenyl-type epoxy resin (YX4000H manufactured by Yuka Shell Epoxy Co., Ltd., 9.6 parts by weight) Phenol aralkyl resin (Mitsui Toatsu Co., Ltd., XL-225) 6.9 parts by weight

Wax (P-1) 0.5 parts by weight

Embedded image 1,8-diazabicyclo (5,4,0) undecene-7 (DBU) 0.2 parts by weight Spherical fused silica (average particle size 15 μm) 80.0 parts by weight Carbon black 0.3 part by weight Brominated phenol novolak epoxy Resin 1.0 part by weight Antimony trioxide 1.0 part by weight Epoxysilane coupling agent 0.5 part by weight is mixed at room temperature using a mixer, kneaded at 50 to 130 ° C. using a biaxial roll, and cooled. Crushed into molding material,
This was tableted to obtain a resin composition. This resin composition was transferred to a low-pressure transfer molding machine (molding conditions: 175).
(70 ° C., 70 kg / cm ² , 120 seconds), and the obtained molded article was post-cured at 175 ° C. for 8 hours and evaluated. Table 1 shows the evaluation results.

<< Evaluation method >> Release property and mold fouling property: Low pressure transfer molding machine
A molding test was performed using a mold for 160 pQFP.
The mold releasability of a molded article molded at a molding temperature of 175 ° C. and a curing time of 120 seconds was organoleptically evaluated in three stages of ○, Δ, and ×. Furthermore,
The state of the surface of the obtained molded article was visually observed, and the stain on the mold was evaluated in three stages of ○, Δ, and ×. Solder resistance: 80pQFP at 175 ° C, curing time 120 seconds
A (1.5 mm thick) molded product was obtained and subjected to post-curing at 175 ° C. for 8 hours to obtain a sample. 6 for each sample
I got each package. After being charged in a thermo-hygrostat at 85 ° C. and a relative humidity of 85% for 168 hours, an IR reflow treatment at 240 ° C. was performed. Observe the peeling inside the package after processing using an ultrasonic flaw detector and count the number of packages with peeling on the chip surface and the number of packages with peeling on the back of the pad, respectively. ) Was determined.

Examples 2 to 14 and Comparative Examples 1 to 4 In accordance with the formulations shown in Tables 1 to 3, a molding material was evaluated in the same manner as in Example 1 and evaluated in the same manner as in Example 1. Hereinafter, (E-1) to (E-4) used in Examples and Comparative Examples,
The structural formulas of (H-1), (H-2), and (P-2) to (P-8) are shown.

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[0017]

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[0018]

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[0019]

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[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

The epoxy resin composition of the present invention has excellent releasability from a mold at the time of molding and excellent adhesion to various substrates.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H01L 23/31 H01L 23/30 R // C08L 35/00 LHS (C08L 63/00 23:00)

Claims (1)

[Claims] An epoxy resin, a phenol resin curing agent,
Curing accelerator, inorganic filler, formula (1) and / or formula (2)
An epoxy resin composition for encapsulating a semiconductor, comprising the wax described above, and containing 0.02 to 1% by weight of the total resin composition. Embedded image