JP3032067B2 - Epoxy resin composition - 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 for semiconductor encapsulation which has excellent resistance to soldering stress and moisture during surface mounting of a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, semiconductor devices such as integrated circuits, transistors and diodes are sealed with a thermosetting resin. In particular, in the case of integrated circuits, ortho-cresol novolak epoxy resin having excellent heat resistance and moisture resistance is made of a novolak type. An epoxy resin composition cured with a phenol resin is used. However, in recent years, there has been a remarkable tendency to increase the size of chips and reduce the size and thickness of packages due to the high integration, multifunctionality, and rationalization of semiconductor devices. Package S
The ratio of OJ, SOP, QFP, etc. is increasing.

A surface mount type package in which a large chip is enclosed in a small and thin package is rapidly exposed to a high temperature of 200 ° C. or more in a soldering process, receives a large stress, breaks the package, and causes the chip to be sealed with a sealing resin. A phenomenon such as separation of the interface of the semiconductor device occurs, which is a fatal problem in the reliability of the semiconductor device. Therefore, development of a highly reliable encapsulating resin composition suitable for encapsulating these surface mount packages is urgent.

In order to solve these problems, addition of thermoplastic oligomers (Japanese Patent Application Laid-Open No. 62-15849) and addition of various silicone compounds (Japanese Patent Application Laid-Open No. No. 115850, 62
JP-A-116654 / 62-128162) and silicone modification (Japanese Patent Laid-Open No. 62-136860), all of which have cracks in the package at the time of soldering and have excellent reliability. It has not been possible to obtain an epoxy resin composition for semiconductor encapsulation.

On the other hand, in order to obtain an epoxy resin composition for semiconductor encapsulation having excellent heat stress resistance during soldering, that is, excellent solder stress resistance, a biphenyl type epoxy resin is used as a resin system (Japanese Patent Application Laid-Open No. 64-65116). Publication) has been studied, but the use of a biphenyl type epoxy improves the adhesion to the lead frame and low water absorption, reduces the occurrence of cracks, but is inferior in heat resistance, especially at a high temperature of 250 ° C. or higher. The solder stress resistance is still insufficient.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition for semiconductor encapsulation which is excellent in solder stress resistance and moisture resistance without deteriorating the reliability against such a problem. .

[0007]

The epoxy resin composition of the present invention comprises, as an epoxy resin (A), 1,6-bis (2,3-epoxypropoxy) naphthalene represented by the formula (1) as a total epoxy resin: An epoxy resin containing 30 to 100% by weight based on the amount;

[0008]

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(B) a trifunctional phenol resin curing agent represented by the chemical structural formula of the formula (2):

[0010]

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(Wherein R _{1 to} R ₁₁ are the same or different atoms or groups selected from hydrogen, halogen, and alkyl group) in an amount of 50 to 1 with respect to the total amount of the phenol resin curing agent.
A resin composition for semiconductor encapsulation containing, as essential components, a phenolic resin curing agent containing 00% by weight, (C) an inorganic filler, and (D) a curing accelerator, and has a much better soldering resistance than conventional epoxy resins. It has the property.

The epoxy resin represented by the formula (1) used in the present invention is 1,6-bis (2,3-epoxypropoxy) naphthalene, which shows a semi-solid property at room temperature and a molding temperature (175 ° C.) In this case, the viscosity is very low, so that the amount of the filler added can be greatly increased. From this, in addition to the characteristics of the resin body that is excellent in low water absorption, the coefficient of linear expansion of the resin is small, and the mold releasability at the time of molding is excellent, the resin composition highly filled with a filler has a high water absorption and linearity. It has the characteristics of having a smaller expansion coefficient and excellent impact strength, and shows good results in resistance to soldering stress during soldering. By adjusting the amount of 1,6-bis (2,3-epoxypropoxy) naphthalene used, the solder stress resistance can be maximized by adjusting the amount.

In order to obtain the effect of resistance to soldering stress, 1,6-bis (2,3-epoxypropoxy) naphthalene is used in an amount of 30% by weight or more, preferably 60% by weight of the total epoxy resin.
It is desirable to use not less than weight%. If the content is less than 30% by weight, low water absorption and low coefficient of linear thermal expansion cannot be sufficiently obtained, and solder stress resistance is insufficient. When an epoxy resin other than 1,6-bis (2,3-epoxypropoxy) naphthalene is used in combination, the epoxy resin used generally refers to any polymer having an epoxy group. For example, trifunctional epoxy resins such as bisphenol type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin, phenol novolak type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, and epoxy resin containing triazine nucleus And so on.

The trifunctional phenol resin curing agent having the structure represented by the formula (2) is a phenol resin curing agent having three hydroxyl groups in one molecule. The feature is that the crosslink density of the reaction cured product with the epoxy resin is improved, and the glass transition temperature is improved. Therefore, it is suitable for resistance to soldering stress during soldering for recent surface mounting. By adjusting the amount of the trifunctional phenol resin curing agent used, the solder stress resistance can be maximized. In order to obtain the effect of resistance to soldering stress, it is desirable to use the trifunctional phenolic resin curing agent represented by the formula (2) in an amount of 50% by weight or more, preferably 70% by weight or more of the total amount of the phenolic resin curing agent. If it is less than 50% by weight, the crosslink density does not increase and the soldering stress resistance is insufficient.

In the formula, R ₁ , R ₂ , R _{4 to} R ₇ ,
R ₁₀ and R ₁₁ are preferably hydrogen atoms, and R ₃ , R ₈ and R ₉ are preferably methyl groups. Further, with a phenol resin curing agent having two or less functions, the crosslink density does not increase, and the solder stress resistance tends to decrease. When other phenol resin curing agents are used in addition to the trifunctional phenol resin curing agent represented by the formula (2),
The phenol resin curing agent used refers to all polymers having a phenolic hydroxyl group. For example, phenol novolak resins, cresol novolak resins, dicyclopentadiene-modified phenol resins, co-condensates of dicyclopentadiene-modified phenol resins with phenol novolak and cresol novolak resins, para-xylene-modified phenol resins, and the like can be used.

The inorganic filler used in the present invention includes fused silica powder, spherical silica powder, crystalline silica powder, secondary aggregated silica powder, porous silica powder, secondary aggregated silica powder or silica obtained by pulverizing porous silica powder. Powder, alumina and the like, and a fused silica powder is particularly preferable. The amount of the inorganic filler is 70 to 90% by weight in the total resin composition in consideration of the balance between solder stress resistance and moldability.
Is preferred.

The curing accelerator used in the present invention may be any one which promotes the reaction between the epoxy resin and the phenolic hydroxyl group, and those generally used for sealing materials can be widely used. For example, organic phosphine compounds such as triphenylphosphine (TPP), tributylphosphine and tri (4-methylphenyl) phosphine, tributylamine, triethylamine, dimethylbenzylamine (BDMA), trisdimethylaminomethylphenol, and diazabicycloundecene (DBU) ) And imidazole compounds such as 2-methylimidazole, 2-phenylimidazole and 2-ethyl-4-methylimidazole. These can be used alone or 2
It is used by mixing more than one kind.

The epoxy resin composition for encapsulation of the present invention comprises an epoxy resin, a curing agent, an inorganic filler and a curing accelerator as essential components. In addition to this, a silane coupling agent and a brominated epoxy resin may be used if necessary. Various additives such as flame retardants such as antimony trioxide and hexabromobenzene, coloring agents such as carbon black and red iron oxide, release agents such as natural wax and synthetic wax, and low stress additives such as silicone oil and rubber. It may be properly compounded. In addition, in order to produce the encapsulating epoxy resin composition of the present invention as a molding material, the epoxy resin, curing agent, curing accelerator, filler, and other additives are sufficiently uniformly mixed by a mixer or the like, and then further heated. Melt and mix with a roll or kneader, etc.
After cooling, it can be pulverized into a molding material. These molding materials can be applied to sealing, coating, insulating and the like of electronic parts or electric parts.

[0019]

The present invention will be described below by way of examples. The mixing ratio is by weight. Example 1 The following composition 1,6-bis (2,3-epoxypropoxy) naphthalene (epoxy equivalent 150) 12.4 parts by weight Trifunctional phenol resin curing agent represented by the formula (3) (hydrogen group equivalent 141) 11 .6 parts by weight

[0020]

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75.0 parts by weight of fused silica powder 0.2 parts by weight of triphenylphosphine 0.3 parts by weight of carbon black 0.5 parts by weight of carnauba wax are mixed at room temperature with a mixer, and are mixed at 70 to 100 ° C. with a biaxial roll. The mixture was kneaded, cooled and pulverized to obtain a molding material, which was tabletted to obtain an epoxy resin composition for semiconductor encapsulation. This composition was molded using a low-pressure transfer molding machine (molding conditions: 175 ° 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 test results.

Evaluation method * 1 Spiral flow Using a mold for measuring spiral flow in accordance with EMMI-I-66, 15 g of a sample was molded at a molding temperature of 175 ° C, a molding pressure of 70 kg / cm ² , and a molding time of 2 minutes. * 2 Solder stress test Molded product (chip size 36 mm ² , package thickness 2.0
5 mm) 20 pieces were treated in an atmosphere of 85 ° C. and 85% RH for 72 hours, then immersed in a solder bath at 260 ° C. for 10 seconds,
Shows the number of cracked molded products. * 3 Solder Moisture Resistance Test The sealed test element was treated at 85 ° C. in an atmosphere of 85% RH for 72 hours, then immersed in a 240 ° C. solder bath for 10 seconds, and then subjected to a pressure cooker test (125 ° C., 10%).
0% RH), and the number of open defects of the circuit was measured.

Examples 2 to 4 The components were blended according to Table 1, and an epoxy resin composition was obtained in the same manner as in Example 1. The same test as in Example 1 was performed using this composition. Table 1 shows the results.

Comparative Examples 1 to 5 Compounded according to Table 1, and an epoxy resin composition was obtained in the same manner as in Example 1. The same test as in Example 1 was performed using this composition. Table 1 shows the results.

[0025]

[Table 1]

[0026]

The epoxy resin composition for encapsulating a semiconductor according to the present invention is extremely excellent in solder stress resistance and moisture resistance, and thus is suitable as a resin composition for encapsulating a surface mount package.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI C08L 63/00 C08L 63/00 H01L 23/31 (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 23/29 C08G 59 / 20 C08G 59/62 C08K 3/36 C08K 5/5313 C08L 63/00 H01L 23/31

Claims (1)

(57) [Claims] (1) 1,6-bis (2,3-epoxypropoxy) represented by the formula (1) as an epoxy resin:
An epoxy resin containing naphthalene in an amount of 30 to 100% by weight based on the total amount of the epoxy resin; (B) a trifunctional phenol resin curing agent represented by the chemical structural formula of the formula (2) as a phenol resin curing agent: (Wherein R _{1 to} R ₁₁ are the same or different atoms or groups selected from hydrogen, halogen and alkyl groups) a phenol resin curing agent containing 50 to 100% by weight based on the total phenol resin curing agent amount; An epoxy resin composition for semiconductor encapsulation comprising (C) an inorganic filler and (D) a curing accelerator as essential components.