JP2938174B2 - Resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an epoxy resin composition excellent in solder heat resistance suitable for a highly integrated resin composition for IC encapsulation.

[Conventional technology]

Conventionally, electronic components such as diodes, transistors, and integrated circuits are sealed with a thermosetting resin. Especially for integrated circuits, 0-cresol novolak epoxy resin, which has excellent heat resistance and moisture resistance, is cured with a novolak type phenol resin. Epoxy resin is used.

However, in recent years, chips have become larger and larger as integrated circuits have become more highly integrated, and packages have become smaller, thinner flat packages that have been surface mounted from conventional DIP types,
It is changing to SOP, SOJ, PLCC.

That is, a large chip is sealed in a small and thin package, and cracks are generated due to stress, and problems such as a decrease in moisture resistance due to the cracks have been greatly highlighted.

In particular, there is a problem that the package is cracked due to sudden exposure to a high temperature of 200 ° C. or more in the soldering process, and the moisture resistance is deteriorated due to the separation of the resin and the chip.

There is a demand for a highly reliable sealing resin composition suitable for sealing these large chips.

In order to solve these problems, thermoplastic oligomers were added to alleviate the thermal shock during soldering (Japanese Patent Laid-Open No.
No. 1-115849), addition of various silicone compounds (Japanese Patent Application Laid-Open No. 62-11585, Japanese Patent Application Laid-Open No. 62-116654 and Japanese Patent Application Laid-Open No. 62-128162), and further, silicone modification (Japanese Patent Application Laid-Open No. 62-136860). However, in any case, cracks occurred in the package at the time of soldering, and it was not possible to obtain a highly reliable epoxy resin composition for semiconductor encapsulation.

[Problems to be solved by the invention]

An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation having excellent solder heat resistance.

[Means for solving the problem]

The present inventors have intensively studied to solve these problems, and have found a resin composition having the following composition.

Epoxy resin having the following structure is 30 ~
100% blended, (R ₁ is hydrogen or a methyl group) and a phenol novolak-based curing agent represented by the following formula is blended in an amount of 30 to 100% by weight of the total curing agent, Furthermore, it has been found that a resin composition for semiconductor encapsulation which can improve the above-mentioned problems can be obtained by blending a curing accelerator and an inorganic filler, thereby completing the present invention.

(Operation)

The biphenyl type epoxy compound as the component (A) used in the present invention has three effects effective for solder heat resistance, toughness, low elasticity, and low viscosity. These effects are represented by the formula [I]
This is due to the chemical structure shown in FIG. That is, the packing between the molecules is improved due to the planar structure, and the effect of the intermolecular attraction is increased, so that the toughness is developed, the durability against the heat stress and the water vapor pressure is increased, and the solder heat resistance is improved. Further, since it is a low molecule having only two epoxy groups in one molecule, a resin structure having a low crosslink density is obtained, and the elastic modulus, particularly in the region above Tg, is remarkably reduced. The lower range of the thermal stress due to the lowering of the elastic modulus leads to the improvement of the solder heat resistance as a matter of course. Furthermore, since it is a low molecular crystalline compound, the melt viscosity is extremely low at several centipoise at around 175 ° C., and it becomes a compounding system to which a much larger amount of filler can be added as compared with a normal resin system. As the amount of filler increases, low water absorption, high strength, and low stress occur, and the solder heat resistance also improves.

The biphenyl type epoxy compound represented by the formula (I) is
It must account for 30 to 100% by weight of the total epoxy resin. If the amount is less than 30% by weight, the above effects are not sufficiently exhibited, and the solder heat resistance is reduced. The epoxy resin used in combination refers to any epoxy resin having an epoxy group. For example, it refers to a bisphenol-type epoxy resin, a novolak-type epoxy resin, or the like.

The imide ring-containing phenol novolak curing agent as the component (B) used in the present invention is effective for soldering heat resistance, that is, it has high Tg in addition to toughness, low elasticity, and improved adhesion to metals. Having. That is,
Like the biphenyl-type epoxy compound of the component (A), the compound has a planar structure in the molecule, so that toughness and low elasticity occur. Furthermore, since the imide ring also has a polar structure containing N and O atoms, the adhesion to metal is improved, which is effective in improving solder heat resistance and moisture resistance after soldering.

Although there was a concern that the water absorption was improved due to the polarity, the water absorption was not substantially changed as compared with the case where a normal phenol novolak resin was used.

In addition, when a group having no reactivity is usually introduced into a side chain,
Certainly, toughness and low elastic modulus occur, but Tg decreases. Nevertheless, when an imide ring is introduced, Tg is improved, moldability and moisture resistance are improved, and handling becomes extremely easy. It is thought that the suppression of the molecular motion of the main chain by the giant molecule is caused by the planarity of the imide ring.

In the imide ring-containing phenol novolak represented by the formula (II), Is desirably 0.05 or more and 0.8 or less. When it is less than 0.05, the effect of the imide ring is not sufficient, and the solder heat resistance is insufficient. On the other hand, when it is larger than 0.8, the amount of phenolic OH is very small, so that the curability, moldability, Tg, etc. are reduced.

The imide ring-containing phenol novolak represented by the formula [II] needs to account for 30 to 100% by weight of the total amount of the curing agent. If it is less than 30%, the above effects are not sufficiently exhibited, and the solder heat resistance is reduced. The curing agent to be used in combination may be any one having a phenolic OH group in the molecule, and examples thereof include a phenol novolak curing agent.

The component (A) and the component (B) are the most important materials of the present invention. By using both of them, the solder heat resistance is greatly improved due to a synergistic effect. It is thought that the reason for the sufficient synergistic effect obtained by the combined use of both is that the fact that all have a planar structure in the molecule is the point of improving the physical properties, and that the performance was improved without canceling the advantages of each other. Can be

As the curing accelerator as the component (C) of the present invention, any one can be used as long as it promotes the reaction between the epoxy group and the phenolic hydroxyl group, and those generally used as a sealing material can be widely used. For example, tertiary amines such as BDMA, imidazoles, 1,8-diazabicyclo [5,4,0]
Organic phosphorus compounds such as undecene-7 and triphenylphosphine are used alone or in combination of two or more.

Examples of the inorganic filler as the component (D) of the present invention include crystalline silica, fused silica, alumina, calcium carbonate, talc, mica, glass fiber, and the like. These may be used alone or as a mixture of two or more. You. Among them, crystalline silica or fused silica is particularly preferably used.

In addition, if necessary, a release agent such as wax, a flame retardant such as hexabromobenzene, decabromobiphenyl ether, antimony trioxide, a coloring agent such as carbon black and red iron, a silane coupling agent and other thermoplastic resins are appropriately used. It can be added and blended.

As a general method for producing the epoxy resin composition for semiconductor encapsulation of the present invention, after sufficiently mixing the raw materials of a predetermined mixing ratio by a mixer or the like, further melt-kneading treatment by a roll or a kneader, Then, it can be easily manufactured by cooling and solidifying and pulverizing to an appropriate size.

〔Example〕

The present invention is described in the following examples. The mixing ratio is expressed in parts by weight.

Example 1 Biphenyl type epoxy compound (A) 90 parts by weight Brominated bisphenol A type epoxy resin (softening point 65
℃, bromine content 37%, epoxy equivalent 370) 10 parts by weight Imide ring-containing phenol novolak resin (c) 95 parts by weight Fused silica 500 parts by weight Antimony trioxide 10 parts by weight Silane coupling agent 2 parts by weight triphenylphosphine 2 parts by weight carbon black 3 parts by weight Carnauba wax 3 parts by weight is sufficiently mixed at room temperature, further kneaded at 95 to 100 ° C. with a biaxial roll, cooled and pulverized to form a molding material. An epoxy resin composition for stopping was obtained.

This material was molded using a transfer molding machine (molding conditions: mold temperature: 175 ° C., curing time: 2 minutes), and the obtained molded article was post-cured at 175 ° C. for 8 hours and evaluated. First result
It is shown in the table.

Example 2 An epoxy for semiconductor encapsulation was prepared in the same manner as in Example 1 except that 95 parts by weight of the imide ring-containing phenol novolak resin (c) of Example 1 was changed to 100 parts by weight of the imide ring-containing phenol novolak resin (d). A resin composition was obtained.

The evaluation results of the epoxy resin composition for semiconductor encapsulation are given in the first section.
It is shown in the table.

Examples 3 to 4 and Comparative Examples 1 to 4 Similarly, epoxy resin compositions for semiconductor encapsulation having the compositions shown in Table 1 were obtained. Table 1 shows the evaluation results of the epoxy resin composition for semiconductor encapsulation.

* 1 Biphenyl type epoxy compound represented by the following formula [III] (epoxy equivalent: 175) * 2 Biphenyl epoxy resin compound represented by the following formula [IV] (epoxy equivalent: 120) * 3 An imide ring-containing phenol novolak curing agent represented by the following formula [V] (softening point 120 ° C, OH equivalent 175) * 4 An imide ring-containing phenol novolak curing agent represented by the following formula [VI] (softening point 120 ° C, OH equivalent 180) * 5 An imide ring-containing phenol novolak curing agent represented by the following formula [VII] (softening point 125 ° C, OH equivalent 210) * 6 An imide ring-containing phenol novolak curing agent represented by the following formula [VIII] (softening point 110 ° C, OH equivalent 110) * 7 An imide ring-containing phenol novolak curing agent represented by the following formula [IX] (softening point 130 ° C, OH equivalent 1400) * 8 Bacoal hardness of molded product 10 seconds after mold opening after molding at 175 ° C for 2 minutes.

* 9 Using a Tensilon bending machine, 250 ° C, load speed 1
Measured at 0 mm / min.

 3-point bending with span of 64mm, width of 10mm and thickness of 4mm.

* 10 Molded product (chip size 36 mm ² , package thickness 2 mm)
For 20 samples, the number of cracks is shown after performing an IR reflow process at 240 ° C. after performing a process for 72 hours under steam at 85 ° C. and 85% RH.

* 11 Molded product (chip size 36mm ² , package thickness 2mm)
After performing VPS treatment at 215 ° C for 20
Shows the number of IC chips that have been processed for 500 hours under steam at 100 ° C and 100% RH.

〔The invention's effect〕

The resin composition for semiconductor encapsulation containing the biphenyl type epoxy resin, the imide ring-containing phenol novolak curing agent, the curing accelerator, and the inorganic filler as essential components of the present invention has excellent solder heat resistance and moisture resistance, and has a high degree of integration. It is very reliable as a resin composition for IC encapsulation.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 23/31 (56) References JP-A-4-227624 (JP, A) JP-A-4-153214 (JP, A) JP-A-53-134097 (JP, A) JP-A-4-20518 (JP, A) JP-A-3-197527 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08G 59 / 24 C08G 59/62 C08L 63/00-63/10 H01L 23/29

Claims (1)

(57) [Claims] 1. A biphenyl type epoxy compound represented by the following formula [I]: (Wherein R ₁ is hydrogen or a methyl group) 30 to 100% by weight based on the total amount of epoxy resin (B) An imide ring-containing phenol novolak curing agent having a structure represented by the following formula [II] Is a phenol novolak-based curing agent containing 30 to 100% by weight based on the total amount of the curing agent. (C) A curing accelerator (D) An epoxy resin composition for semiconductor encapsulation containing an inorganic filler as an essential component.