JPH1192550A - Liquid epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealing liquid epoxy resin composition having low viscosity, excellent storage stability and good curability by using as essential components an epoxy resin being an alicyclic epoxy resin and a curing agent being a catalyst system comprising a phenolic curing agent, a metal chelate catalyst and acetylacetone. SOLUTION: This composition contains an epoxy resin, a curing agent and a filler. The phenolic curing agent used is exemplified by a bisphenol A or novolac phenolic resin. The metal chelate catalyst used is an acetylacetonate of aluminum, titanium, zinc, zirconium or copper. The metal chelate catalyst is used in an amount of about 0.01-5.0 wt.% based on the weight of the epoxy resin. The acetylacetone which together with the metal chelate catalyst constitutes the catalyst system is used in an amount of about 0.2-3 pts.wt. per pt.wt. metal chelate catalyst. The filler is desirably spherical especially spherical fused silica or spherical alumina.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solvent-free or high-solid liquid epoxy resin composition for sealing electric parts, electronic parts, semiconductor devices and the like.

[0002]

2. Description of the Related Art Semiconductor device encapsulation is roughly classified into a powder transfer molding epoxy encapsulant using a mold and a liquid epoxy encapsulant. is there. On the other hand, a liquid epoxy encapsulant that does not use a mold has been used only in a specific field, but a plastic pin grid array (P-PG
A), plastic ball grid array (P-BG
A), hybrid IC, multi-chip module (M
CM) and other semiconductor devices for higher functionality, lighter weight,
With the transition of package trends such as large-area encapsulation and low-cost devices, the existence of liquid encapsulants has been reviewed, and large growth of liquid encapsulants is expected in the 21st century.

[0003] Liquid epoxy encapsulants are broadly classified into solvent type and non-solvent type. The solvent type uses a phenol resin as the resin, and can increase the filling rate of the filler to reduce the coefficient of thermal expansion, and is a material excellent in thermal shock resistance and workability. Although there are problems such as that the coating film is porous, flammability due to the use of a solvent, and a long curing process, it is used in specific fields because of its good thermal shock resistance. The solventless type uses a bisphenol A type or bisphenol F type epoxy resin as an epoxy resin, and as a curing agent, a curing agent and a curing accelerator such as an acid anhydride, an amine, an imidazole, and a phenol are used.

The liquid encapsulant for semiconductors has a low viscosity from the viewpoint of workability of application, and has a low thermal expansion in order to prevent the occurrence of interface delamination when thermal stress is applied in accordance with the coefficient of thermal expansion with the substrate, so that warpage is low. Less. From the corrosive aspect of an IC chip, performance such as low ionic impurities and good storage stability is required. At present, the use of acid anhydride curing agents occupies the mainstream due to the above-mentioned restrictions on lowering the viscosity and lowering the thermal expansion of the cured product. The acid anhydride curing agent is susceptible to hydrolysis of an ester group generated by curing, and has a high moisture absorption under high temperature and high humidity. In addition, they have poor storage stability and require frozen storage. In use, free acid is generated under the influence of moisture in the air. For example, when used for screen printing, there is a problem in that the humidity is sufficiently controlled and used.

[0005] A phenol-based curing agent is one method for achieving this improvement, but has the disadvantage of high viscosity.
In order to compensate for this drawback, a combination of an acid anhydride and a phenol is used, but it has not been satisfactory as a liquid sealing material. As described above, the development of a material having good storage stability for lowering the viscosity of the material and improving workability is strongly desired, and it can be said that this is a major problem of the liquid sealing material.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems in the prior art. It is an object of the present invention to provide a sealing epoxy resin composition comprising a catalyst system having low viscosity, excellent storage stability and good curability.

[0007]

Means for Solving the Problems The present inventor has conducted various studies to achieve the above object, and as a result, has solved the above object, thus completing the present invention. That is, the present invention provides a liquid epoxy resin composition containing an epoxy resin, a curing agent, and a filler, wherein the epoxy resin is an alicyclic epoxy resin as an essential component, and the curing agent is a phenolic curing agent, a metal chelate catalyst, and acetylacetone. An epoxy resin composition comprising a catalyst system comprising:

[0008] In order to solve the problem of lowering the viscosity in the present invention, an attempt was made to use an alicyclic epoxy resin, and more preferably, to perform a close packing with a spherical filler. The alicyclic epoxy resin is generally produced by an epoxidation reaction with peracetic acid, and includes (3 ′, 4′-epoxycyclohexylmethyl) -3,4-epoxycyclohexanecarboxylate, (3 ′, 4 '-Epoxy-6'-
Methylcyclohexylmethyl) -3,4-epoxy-6
-Alicyclic epoxy resins such as methylcyclohexanecarboxylate, vinylcyclohexene dioxide, dicyclopentagendioxide and the like are known. Celloxide 2021, Celloxide 2083, Celloxide 3000, manufactured by Daicel Chemical Industries, Ltd., ERL-4221, ERL-4289, ERL-, manufactured by Union Carbide.
4206 and CY-179, CY manufactured by Ciba Geigy
It is commercially available under the trade name -178.

The alicyclic epoxy resin has a very low viscosity at room temperature, and the cured product has excellent heat resistance. Since it does not contain a benzene nucleus, it has good weather resistance and tracking resistance. In addition, there are features such as a low content of hydrolyzable chlorine and ionic impurities. On the other hand, the cured product is fragile and has a disadvantage that curing shrinkage is relatively large because it is crosslinked at once from a low molecular weight to become a polymer, and has not been used for electronic parts at present. The viscosity is 1 compared to liquid bisphenol type epoxy resin.
As low as / 10 to 1/50, it is possible to reduce the viscosity of the sealing material and increase the filling of the filler. The alicyclic epoxy resin is used alone or in combination of two or more.

As the filler, fused silica, crystalline silica,
Alumina or the like is used. Preference is given to spherical fillers, which use spherical fused silica or spherical alumina, preferably with an average particle size of 3 to 25 μm. Further, shape retention during heating can be imparted by using a small amount of crushed silica. Filler is 4 per 100 parts by weight of total epoxy resin
The filler is used in an amount of 0 to 600 parts by weight, and preferably a filler of various particle sizes is used in combination for the closest packing of the filler. In addition, a filler is selected and used depending on the sealing form and application of the sealing material. For example, for the purpose of an underfill material for filling and sealing the gap, it is preferable to use spherical fused silica having an average particle size of 1 to 6 μm.

In the present invention, with respect to the problem of improving the storage stability, the use of a catalyst system containing a phenolic curing agent, a metal chelate catalyst and acetylacetone exhibits excellent stability and good curability. Things. In this catalyst system, the activity of the metal chelate catalyst at a low temperature is suppressed by acetylacetone, and acetylacetone evaporates and disperses as the temperature rises during curing, thereby exhibiting the original curability of the metal chelate catalyst.

The phenolic curing agent used in the present invention includes phenolic compounds such as bisphenol A, pyrogallol catechol, resorcinol, cresol, allylated bisphenol A, novolak type phenol resins, alkylphenol resins, benzyl ether type phenol resins, and phenol aralkyl resins. , Alkenyl group-containing phenolic resin, allyl group-containing phenolic resin, poly-P-
It is a phenolic resin such as vinyl phenol.

The metal chelate catalyst used in the present invention is, for example, a metal chelate catalyst represented by the following formula (1).

Embedded image [Wherein, M is a metal ion, R ₁ and R ₂ are H, CH ₃ , C ₂ H
₅ , C ₃ H ₇ , —OCH ₃ , —OC ₂ H ₅ , or —OC ₃ H ₇ , which may be the same or different.
n is an integer of 1 to 4. ]

When the metal is aluminum, aluminum tris (acetylacetonate), aluminum tris (ethyl acetoacetate), aluminum monoacetylacetonate bis (ethyl acetoacetate) and the like are exemplified. Titanium as a metal in addition to aluminum,
Such as zinc, zirconium, nickel, and copper.
The metal chelate catalyst is used in an amount of 0.01 to 5.0% based on the weight of the epoxy resin. Preferably it is 0.1-3.0%. In addition, a small amount of imidazole and triphenylphosphine (TPP) are used as metal chelate catalysts.
And a hardening accelerator microencapsulated.

The acetylacetone (2,2) used in the present invention
4-pentanedione) suppresses the activity of the metal chelate catalyst at a low temperature and imparts storage stability to the epoxy resin composition. Acetylacetone has a boiling point of 140 ° C., and is scattered and driven off with an increase in temperature during curing, so that the original curability of the metal chelate catalyst can be exhibited. The catalyst system containing acetylacetone in the above-mentioned metal chelate catalyst can exhibit excellent storage stability and good curability. Acetyl acetone is suitably used in an amount of 0.2 to 3 parts by weight per 1 part by weight of the metal chelate catalyst.

The liquid epoxy resin composition of the present invention may contain a small amount of a liquid epoxy resin such as bisphenol A type or bisphenol F type. Also, if necessary, a small amount of a solvent, a reactive diluent, an antifoaming agent, a coloring agent such as carbon black, an antimony trioxide or a brominated epoxy resin, a flame retardant such as red phosphorus, and a silane coupling agent such as epoxy silane. Additives such as silicone oil, epoxidized polybutadiene, flexible agents such as carboxylic acid-terminated acrylonitrile butadiene rubber, and thixotropic agents such as finely divided silica can be appropriately added and blended.

The liquid epoxy resin composition of the present invention is usually used without a solvent, but a high-solid composition may be prepared by blending a small amount of a solvent in order to increase the filling and lower the coefficient of thermal expansion. Solvents used for the high solid type include aromatic hydrocarbons such as toluene and xylene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diacetone alcohol; ethers such as propylene glycol methyl ether; and esters such as butyl acetate. ,
Alcohols such as butanol and the like are used alone or in combination of two or more.

The reactive diluent used for the solventless type is butyl glycidyl ether (BGE), phenyl glycidyl ether (PGE), cresol glycidyl ether (C
GE), monoepoxy compounds such as styrene oxide (SO), polyepoxy compounds such as diglycidyl ether (DGE), diallyl phthalate, glycidyl methacrylate, and lactone.

The epoxy resin composition of the present invention comprises an alicyclic epoxy resin, a spherical filler, a metal chelate catalyst, acetylacetone and, if necessary, additives such as a solvent, a reactive diluent, and a thixotropic agent. It is manufactured by mixing using a mixer and then degassing under reduced pressure as necessary. The composition thus obtained contains 3 ppm or less of ionic impurities typified by free sodium ions and free chloride ions by using an alicyclic epoxy resin, and
The viscosity is stable for more than one month when stored at ℃. Also 150
It can be cured at ~ 160 ° C for 2 hours. A semiconductor device or the like is sealed by dispenser application and screen printing using the epoxy resin composition obtained in this manner. The cured composition exhibits excellent moisture resistance and a coefficient of thermal expansion (1-5) × 10 at a glass transition temperature of 200 ° C. or higher.
^It has a performance of ^-5 .

[0020]

The present invention will be described below in detail with reference to examples. Note that “parts” and “%” described in Examples and Comparative Examples all indicate “parts by weight” and “% by weight”.

Examples 1 to 5 and Comparative Example 1 A liquid epoxy resin composition was obtained by mixing at a mixing ratio as shown in Table 1 with a planetary mixer for 2 hours. The viscosity, storage stability, glass transition temperature, adhesion, and solvent resistance of the obtained epoxy resin composition were evaluated by the following methods. Table 2 shows the characteristic evaluation results.

The evaluation was performed as follows. 1. Viscosity The viscosity at 25 ° C. was measured using a Visco tester viscometer. 2. Storage The epoxy resin composition was stored at a temperature of 25 ° C., and the number of days at which the viscosity doubled was determined. 3. Glass transition point After flowing the epoxy resin composition into a mold, the temperature was 70 ° C. 30
Min, 100 ° C. for 30 minutes, 150 ° C. for 2 hours, cut the cured product into a size of 5 × 5 × 10 mm to make a test piece,
The measurement was performed at a heating rate of 5 ° C. per minute by TMA. 4. Adhesiveness After dropping the epoxy resin composition onto an alumina substrate to a diameter of 5 mm (about 0.1 ml), the temperature was set to 70 ° C. for 30 minutes,
The composition was cured at 30 ° C. for 30 minutes and at 150 ° C. for 2 hours to prepare test pieces for evaluation. The load until the test piece was peeled off using a push-pull gauge was measured, and the adhesion strength was indicated in kg / 5 mmφ. 5. Solvent Resistance After pouring the epoxy resin composition into a 50 × 50 mm mold, the composition was cured at a temperature of 70 ° C. for 30 minutes, at a temperature of 100 ° C. for 30 minutes and at a temperature of 150 ° C. for 2 hours to prepare a test piece for evaluation. The hardness of this test piece was measured by a Barcol hardness tester after immersion in acetone and after immersion in acetone for 1 hour, and the solvent resistance was evaluated based on the degree of change in hardness.

[0023]

[Table 1]

Alicyclic epoxy resin (A): BRL-4221 (Union Carbide Co., Ltd.) Alicyclic epoxy resin (B): Celloxide 3000 (Daicel Chemical Industries, Ltd.) Alkyl phenol resin: Cresol formaldehyde novolak resin Spherical Fused silica: FB-35 (Electrochemical Co., Ltd.) Spherical alumina: AS-30 (Showa Denko Co., Ltd.)

[0025]

[Table 2]

[0026]

The liquid epoxy resin composition of the present invention can be reduced in viscosity even when filled with a large amount of filler, and has good preservability, so that it is easy to handle and excellent in workability. Furthermore,
This composition is quick-curing, has a high glass transition point of the cured product, and has excellent adhesion to a substrate. Therefore, the liquid epoxy resin composition of the present invention can be effectively used for encapsulating semiconductor devices.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 63/00 C08L 63/00 BC H01L 23/29 H01L 23/30 R 23/31

Claims (3)

[Claims] 1. A liquid epoxy resin composition containing an epoxy resin, a curing agent and a filler, wherein the epoxy resin is an alicyclic epoxy resin as an essential component, and the curing agent is a phenolic curing agent, a metal chelate catalyst and acetylacetone. An epoxy resin composition comprising a catalyst system comprising: 2. The epoxy resin composition according to claim 1, wherein the metal chelate catalyst is acetylacetonate of aluminum, titanium, zinc, zirconium or copper. 3. The epoxy resin composition according to claim 1, wherein the filler is spherical fused silica and spherical alumina.