JP2933705B2 - Resin composition - Google Patents

Description

The present invention relates to an epoxy resin composition having excellent thermal shock resistance, solder heat resistance and low viscosity suitable for a highly integrated IC sealing resin composition. is there.

[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, by encapsulating a large chip in a small and thin package, cracks due to stress and problems such as a decrease in moisture resistance due to the cracks have been greatly highlighted.

In particular, an encapsulating resin capable of clearing two points of thermal shock resistance and solder heat resistance is required.

In order to improve the thermal shock resistance, addition of silicone compounds such as silicone oil and silicone rubber, and synthetic rubber have been performed. However, these additions cause inconvenient phenomena such as mold stains during molding and generation of resin burrs. Therefore, silicone-modified resins obtained by reacting silicone with an epoxy resin or a curing agent have been developed. (For example, see
No. 21417). The current sealing resin has significantly improved thermal shock resistance due to this utilization. However, these methods are to introduce a low elastic modulus domain into the matrix resin and try to lower the whole elastic modulus, but there is a problem in the adhesiveness between the domain and the matrix, and the elasticity and the strength are also reduced at the same time. However, it is still not enough, and the solder heat resistance tends to decrease, which is a problem. Therefore, it is necessary to improve the thermal shock resistance of the matrix resin itself without adding the low stress imparting agent as described above.

To improve solder heat resistance, consider the use of polyimide resins and fillers and use trifunctional resins (see, for example,
168620) are promising, but all of them are inferior in thermal shock resistance, and are susceptible to defects such as die pad shift due to an increase in the viscosity of the resin composition. It is difficult to obtain a resin composition system.

Therefore, it is considered effective to improve the solder heat resistance while freely changing the composition structure such as the distance between cross-linking points and the main chain structure of the resin to balance various physical properties.

[Problems to be solved by the invention]

An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation which is excellent in heat shock resistance, solder heat resistance, low viscosity and moldability.

[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.

(A) Bifunctional epoxy compound containing two epoxy groups in the molecule (B) Bifunctional phenolic compound containing two phenolic hydroxyl groups in the molecule (C) Three or more phenolic hydroxyl groups in the molecule (D) a polyfunctional epoxy compound containing three or more epoxy groups in the molecule (E) a curing accelerator and (F) an inorganic filler as essential components. / (A) +
(D) = 10-90% by weight, (C) / (B) + (C) = 10-
By using a composition in which 90% by weight and (C) / (C) + (D) = 10 to 90% by weight, thermal shock resistance, solder heat resistance,
The inventors have found that a resin composition for semiconductor encapsulation having low viscosity and excellent moldability can be obtained, and have completed the present invention.

[Action]

Examples of the bifunctional epoxy compound having two epoxy groups in the molecule used in the present invention include bifunctional phenol compounds such as 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylpropane, and 4,4'-.
Dibiphenol, 3,3 ', 5,5'-tetramethyl-4,4'-
Dibiphenol, 1,6-dihydroxynaphthalene, cyclohexylidenebisphenol A, 3,3'-diallyl-
In addition to those obtained by diglycidyl etherification of 4,4'-dihydroxymethane, catechol, resorcin, hydroquinone, and the like, brominated bisphenol A type epoxy resins and alicyclic epoxy compounds can be mentioned.

 These may be used alone or in combination of two or more.

Bifunctional phenolic compounds containing two phenolic hydroxyl groups in the molecule are, in addition to the above-mentioned phenolic compounds,
Add a monomer or oligomer having one phenolic hydroxyl group and an aldehyde such as formaldehyde or salicylaldehyde, or if necessary, a compound having an aromatic ring or an aliphatic ring, and adjust the charging ratio or reaction conditions to adjust the phenolic property. Co-condensates and the like adjusted so that only two hydroxyl groups are contained in the molecule may be mentioned. These may be used alone or in combination of two or more.

Many of these bifunctional epoxy compounds and bifunctional phenol compounds exhibit a low viscosity of several centipoise at a molding temperature (165 to 185 ° C.), and can significantly lower the viscosity of the resin composition. High flowability is given during molding, and lead frames and
High wettability and high adhesion are provided at the chip / island interface, and the solder crack resistance is improved. Further, since the content of the inorganic filler can be greatly increased, the strength at heat, the thermal shock resistance, and the solder crack resistance are further improved.

The phenolic hydroxyl group used in the present invention has 2
Examples of the polyfunctional phenolic compound containing at least two phenolic compounds include phenol novolak, orthocresol novolak, tris (hydroxyalkylphenyl) methane, and other monomers or oligomers having a phenolic hydroxyl group, and the above-described bifunctional phenol compound and formaldehyde. Or aldehydes such as salicylaldehyde,
Alternatively, a co-condensate obtained by adding and reacting a compound having various aromatic rings and resin rings as necessary may be used.

 These may be used alone or in combination of two or more.

Examples of the polyfunctional epoxy compound having three or more epoxy groups in the molecule used in the present invention include those obtained by glycidyl etherification of the above-mentioned polyfunctional phenolic compound, and polyfunctional alicyclic epoxy compounds. These may be used alone or in combination of two or more.

The polyfunctional phenolic compound and the polyfunctional epoxy compound bring about three-dimensional crosslinking with the bifunctional epoxy compound and the bifunctional phenolic compound.

With a bifunctional epoxy compound / phenol compound, a normal reaction produces only a linear high molecular weight compound, but by adding a polyfunctional phenol compound or a polyfunctional epoxy compound, a cross-linking point is three-dimensionally generated, and heat is generated. Produces a cured high molecular weight body. Further, by adjusting the compounding amount of the polyfunctional phenolic compound and the polyfunctional epoxy compound, it is possible to freely adjust the curing properties, the crosslink density, and the distance between the crosslinking points. Cured product properties such as modulus and toughness can be adjusted as desired.

The compounding ratio of these polyfunctional phenolic compounds and polyfunctional epoxy compounds is (polyfunctional phenolic compound) / (2
(Functional phenolic compound + polyfunctional phenolic compound)
10 to 90% by weight, and (polyfunctional epoxy compound) / (bifunctional epoxy compound + polyfunctional epoxy compound) 10 to 90% by weight is appropriate. If it is less than 10% by weight, the curability is significantly poor, and Various properties at the time of heating are greatly reduced.

If it exceeds 90% by weight, the effect of extending the distance between cross-linking points is reduced, and a low elasticity effect and toughness cannot be obtained.

In the case of (polyfunctional phenolic compound) / (polyfunctional phenolic compound + polyfunctional epoxy compound), 10 to 90% by weight is appropriate. If it is less than 10%, the effect of low step is large, but the curability is inferior. The same applies when the amount exceeds the weight%.

The mixing ratio of the epoxy compound and the phenolic compound is preferably in the range of 0.7 to 1.3 in equivalent ratio.

As the inorganic filler used in the present invention, crystalline silica, fused silica, alumina, calcium carbonate, talc,
Mica, glass fiber, etc., and these are one type or two types.
Used as a mixture of more than one species. Among them, crystalline silica or fused silica is particularly preferably used.

Further, the curing accelerator used in the present invention may be any one that promotes the reaction between an epoxy group and a phenolic hydroxyl group, and those generally used for a sealing material can be widely used. 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.

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〕

 Hereinafter, the present invention will be described with reference to Examples.

Examples 1 to 5 and Comparative Examples 1 to 3 The compositions of the respective proportions shown in Table 1 were thoroughly mixed at room temperature, further kneaded at 95 to 100 ° C. with a biaxial roll, cooled and pulverized. This was used as a molding material, and this was formed into a tablet to obtain an epoxy resin composition for semiconductor encapsulation.

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.

Evaluation method * 1. Spiral flow Using a mold for spiral flow measurement according to FMMI-I-66, the molded product was molded at 20 g of sample, molding temperature of 175 ° C, molding pressure of 7.0 MPa, and molding time of 2 minutes. length.

* 2. High flow type flow viscosity at 175 ° C (Poise) * 3. Thermal shock resistance test Molded product (chip size 36mm ² , package thickness 2.05mm,
20 post-curing 175 ° C, 8Hrs) temperature cycle test (+1
(50 ° C to -196 ° C), and the number of cracks is shown by performing a test for 500 cycles.

* 4. Solder heat resistance test Molded product (chip size 36 mm ² , package thickness 2.05 mm) 2
After treating 0 pieces under steam of 85 ° C and 85% RH for 72 hours, 2
Shows the number of cracked molded products immersed in a solder bath at 40 ° C for 10 seconds.

* 5. Molded at a Shore D hardness of 175 ° C and measured 10 seconds after release.

[Effects of the Invention] The resin composition for encapsulating a semiconductor according to the present invention is extremely excellent in thermal shock resistance and soldering heat resistance, has low viscosity, and therefore has excellent gold wire deformability and filling property, and further has good moldability (resin Since the resin composition is excellent in burrs and is a very well-balanced resin composition, it is highly reliable as a highly integrated resin composition for IC encapsulation.

Claims (1)

(57) [Claims] (A) a bifunctional epoxy compound containing two epoxy groups in the molecule; (B) a bifunctional phenolic compound containing two phenolic hydroxyl groups in the molecule; and (C) a phenolic hydroxyl group in the molecule. (D) a polyfunctional epoxy compound containing three or more epoxy groups in the molecule, (E) a curing accelerator and (F) an inorganic filler, as essential components. The ratio is (D) / (A) +
(D) = 10-90% by weight, (C) / (B) + (C) = 10-
An epoxy resin composition for semiconductor encapsulation, wherein 90% by weight and (C) / (C) + (D) = 10 to 90% by weight.