JPH0744242B2 - Epoxy resin composition for semiconductor device encapsulation - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition for semiconductor encapsulation, and more particularly to an epoxy resin composition for semiconductor encapsulation which gives a cured product having excellent thermal shock resistance and moldability.

[0002]

2. Description of the Related Art In recent years, in the field of encapsulation of semiconductor devices, with the high integration of semiconductor elements, the miniaturization of various functional units on the elements and the increase in size of the element pellets have been rapidly progressing. Due to these changes in the element pellets, conventional sealing resins cannot satisfy the requirements for thermal shock resistance and the like. Conventionally, an epoxy resin composition cured with a phenol novolac resin, which has been used as a resin for sealing a semiconductor device, has excellent hygroscopicity, high-temperature electrical characteristics, moldability, and the like, and has become the mainstream of molding resins. .

However, using this type of resin composition,
When a large-sized element pellet having a fine surface structure is sealed, the element pellet surface is cracked into a phosphosilicate glass (PSG) film or a silicon nitride (SiN) film which is a coating material for protecting the aluminum (Al) pattern. May occur or the element pellet may be cracked. This tendency is very large especially when a thermal cycle test is carried out.
As a result, defective device characteristics due to cracking of the pellet and corrosion of the Al pattern due to cracking of the film occur.

As a countermeasure, the stress of the sealing resin with respect to the internal enclosure is reduced, and the sealing resin and the PS on the element are reduced.
It is necessary to increase the adhesion to a glass film such as a G film or a SiN film. For example, in order to reduce the stress of the sealing resin with respect to the internal inclusions, a method of decreasing the thermal expansion coefficient of the resin by increasing the amount of the filler is used.
However, in this case, the use of a large amount of the filler causes a remarkable increase in the viscosity at the time of melting, so that there is a problem that the moldability of the resin is impaired.

Further, along with the change in the element pellets, there has been a problem that reliability is lowered, which is considered to be caused by local stress of the resin and the filler exerted on the chip. It is considered effective to cut coarse particles. In addition, when the package is small and thin, the gate of the molding die is narrower than that of a normal die, and in this case also, the presence of large crushed filler particles is not preferable. However, even if the average particle diameter of the filler is reduced for these purposes, the melt viscosity of the resin may increase, resulting in defective filling or deformation of the bonding wire. Therefore, the damage to the element is small, spherical fillers having good fluidity have been attracting attention, but when spherical fillers having a single particle size distribution are used, burrs that occur during molding become significantly longer, There was a drawback that the strength was reduced.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an epoxy resin composition for semiconductor encapsulation which solves the above problems and gives a cured product having excellent thermal shock resistance and moldability. is there.

[0007]

Means for Solving the Problems In order to achieve the above object, the inventors of the present invention have conducted extensive studies and found that, as a result of the crushed silica powder which is usually used as a filler, a specific spherical silica powder in consideration of the particle size is used. It was found that the semiconductor encapsulating resin in which a predetermined amount of is mixed is excellent in thermal shock resistance and has good moldability, and has completed the present invention.

That is, the epoxy resin composition for semiconductor device encapsulation of the present invention comprises (A) an epoxy resin; (B) a phenol resin curing agent; (C) a curing accelerator; (D) an average particle diameter of 3 to 100 μm. And (E) spherical silica powder having an average particle size of 1 to 50 μm,
The blending amount of the component (E) is 5 to 30% by volume based on the total amount of the components (D) and (E), and the particle size ratio of the component (D) and the component (E) is 1 in the latter case. On the other hand, the former is 3 or more, and the total amount of the components (D) and (E) is (A),
It is characterized by being 50 to 75% by volume with respect to the total blending amount of (B), (C), (D) and (E).

The epoxy resin which is the component (A) of the present invention may be any one as long as it contains at least two epoxy groups in one molecule, for example, bisphenol A type epoxy resin and novolac. Type epoxy resin, alicyclic epoxy resin, and glycidyl ester type epoxy resin, and these are used alone or in a mixture of two or more kinds.

The phenol resin curing agent which is the component (B) of the present invention may be any one generally known as a curing agent for epoxy resins, for example, phenol novolac resin and cresol novolac resin. And novolak type phenolic resins having two or more phenolic hydroxyl groups.

The blending amount of the component (B) is the same as the component 1 of the component (A).
It is usually 30 to 150 parts by weight with respect to 00 parts by weight.
If the amount is less than 30 parts by weight, the curing is insufficient,
If it exceeds the weight part, the moisture resistance is poor. Preferably 50 to 1
It is 00 parts by weight.

The curing accelerator which is the component (C) of the present invention is
When curing epoxy resin using phenolic resin,
Any one is known as long as it is known to be used as a curing accelerator. Specific examples of the component (C) include imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-methylimidazole; benzyldimethylamine, trisdimethylaminomethyl. Tertiary amine compounds such as phenol; organic phosphine compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine, methyldiphenylphosphine and the like can be mentioned, and these can be used alone or in a mixture of two or more kinds.

The blending amount of the component (C) is the same as that of the component (A) 1.
It is usually 0.01 to 10 parts by weight with respect to 00 parts by weight. If it is less than 0.01 part by weight, the curability is poor, and if it exceeds 10 parts by weight, the moisture resistance is lowered.

The crushed silica powder which is the component (D) of the present invention may be any one as long as it has an average particle size in the range of 3 to 100 μm. For example, crystalline silica powder and meltability. Examples thereof include silica powder, or a mixture thereof. When the average particle size is 3 μm, the fluidity is poor,
If it exceeds 100 μm, not only various problems such as gate clogging at the time of molding occur but also a resin-sealed semiconductor element causes malfunction of the element, which is not desirable.

The spherical silica powder which is the component (E) of the present invention has an average particle size in the range of 1 to 50 μm, and may be any as long as the particles have a spherical shape. , Crystalline silica powder, fused silica powder, or a mixture thereof. When the average particle diameter is out of the above range, the effect of improving fluidity during molding is small.

The components (D) and (E) of the present invention are
Component (D) having an average particle size of 5 to 100 μm and an average particle size of 1
˜30 μm of (E) component, and (E) component is 5 to 30% by volume based on the total amount of (D) and (E) component.
When it is blended in, the resulting cured product has excellent thermal shock resistance, which is preferable. In addition, this (D)
The particle size ratio of the component to the component (E) is 1 for the latter and 3 or more for the former. If it is out of this range, the effect of improving the fluidity cannot be sufficiently obtained.

The blending amount of the above-mentioned component (E) is 5 to 30% by volume with respect to the total amount of the components (D) and (E). If the blending amount is out of the above range, the effect of sufficiently improving the fluidity cannot be obtained. Further, the total amount of the above-mentioned components (D) and (E) is (A),
The content is 50 to 75% by volume based on the total amount of the components (B), (C), (D) and (E). When the compounding amount is less than 50% by volume, the obtained cured product cannot have sufficient impact resistance, and when it exceeds 75% by volume, the melt viscosity is increased and the moldability is deteriorated.

In the epoxy resin composition for encapsulating a semiconductor device of the present invention, it is desirable to add an interfacial treatment agent in addition to the above-mentioned components (A) to (E) in order to further improve the effects of the present invention. . This interfacial treatment agent is a mixture of epoxysilane and pure water, and the epoxysilane is represented by the general formula: YSi (OR ₁ ) ₃ (wherein Y is a monovalent organic group having an epoxy group, R ₁ is carbon). Which represents an alkyl group of the formulas 1 to 5) and is, for example, γ-glycidoxypropyltrimethoxysilane. Pure water is pure water such as distilled water and deionized water. In particular, it refers to water which does not contain inorganic or organic ions or ion-generating substances or whose content is extremely small.

As the surface treatment agent, it is preferable to use a mixture of the epoxysilane and pure water in a ratio of 9: 1 to 9.95: 0.05. If it is out of this range, the moisture resistance is poor.

In the composition of the present invention, the above components are melt-kneaded by a heating roll, melt-kneaded by a kneader, melt-kneaded by an extruder, mixed by a special mixer such as fine pulverization, and an appropriate combination of these methods. Can be manufactured by.

If desired, the composition of the present invention may be compounded with a releasing agent such as higher fatty acids and waxes; antimony, phosphorus compounds, known flame retardants containing bromine and chlorine. , Polystyrene, polymethylmethacrylate,
You may add various thermoplastic resins, such as polyvinyl acetate or these copolymers, silicone oil, silicone rubber, etc.

[0022]

EXAMPLES The present invention will be described in more detail below with reference to examples. The compounding ratios in the tables are all parts by weight unless otherwise specified.

Examples 1 to 3 The components of the composition shown in Table 1 were used to obtain the composition of the present invention. First, in a Henschel mixer, the filler is treated with an interfacial treatment agent, and then the remaining components are added and mixed into the mixer, followed by kneading with a heating roll at 60 to 110 ° C. and cooling,
Crushed to obtain the above composition.

As the resins in Table 1, orthocresol novolac type epoxy resin (epoxy equivalent 19
6, softening point 76 ° C.), flame-retardant epoxy resin (epoxy equivalent 270, softening point 30 ° C.), and phenol novolac resin (phenol equivalent 106, softening point 97 ° C.) were used.

[0025]

[Table 1]

Comparative Examples 1 to 8 The components of the compositions shown in Table 2 were mixed in the same manner as in Examples to obtain compositions of Comparative Examples.

[0027]

[Table 2]

Test Examples The following experiments were conducted on the compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 8 above.

That is, in order to evaluate the fluidity of the composition, the melt viscosity at 173 ° C. was measured using a Koka type flow tester.

Further, using the same composition, a large-sized pellet evaluation element having a PSG layer on the surface was sealed by low-pressure transfer molding. In order to evaluate the thermal shock resistance of the obtained sample device, a thermal shock test (-65 ° C to 15 ° C) was performed.
A thermal cycle test (0 ° C.) was performed to measure the characteristics.

A MOS-type IC element is resin-sealed by the low-pressure transfer molding method using the above composition, and a pressure cooker test (test under 2.5 atmospheric pressure) is performed on the obtained resin-sealed semiconductor device. Then, the moisture resistance due to the corrosion of the aluminum electrode was evaluated.

The results are shown in Tables 3-5.

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Table 5]

As is clear from Tables 3 to 5, the inventive products of the examples are superior in thermal shock resistance and moisture resistance to the comparative products, and have an appropriate viscosity when melted. There is.

[0037]

INDUSTRIAL APPLICABILITY The epoxy resin composition for semiconductor encapsulation of the present invention is useful as a package material for semiconductor electronic parts because it has a good moldability and gives a cured product having excellent thermal shock resistance and moisture resistance. And its industrial value is extremely large.

[Brief description of drawings]

FIG. 1 is a diagram showing a particle size distribution curve of silica powder used in Examples and Comparative Examples.

[Explanation of symbols]

 A: crushed fused silica powder, average particle size 20 μm B: crushed fused silica powder, average particle size 3 μm (325 mesh pass, maximum particle size 44 μm) C ... spherical fused silica powder, average particle size 35 μm D ... spherical fused silica powder , Average particle size 3μm

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A 61-85432 (JP, A) JP-A 61-97322 (JP, A) JP-A 61-268750 (JP, A)

Claims (1)

[Claims] 1. (A) Epoxy resin; (B) Phenolic resin curing agent; (C) Curing accelerator; (D) Fractured silica powder having an average particle diameter of 3 to 100 μm; and (E) Average particle diameter 1 Spherical silica powder having a particle size of ˜50 μm, the content of the component (E) is 5 to 30% by volume based on the total amount of the components (D) and (E), and the components (D) and (E) are The particle size ratio of the latter is 1, whereas the former is 3
Above, and the total amount of the components (D) and (E) is 50 to 75% by volume based on the total amount of the components (A), (B), (C), (D) and (E). An epoxy resin composition for semiconductor device encapsulation, comprising: