JPH0651786B2 - Epoxy resin composition for semiconductor device encapsulation - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an epoxy resin composition for semiconductor encapsulation, and more specifically, an epoxy resin for semiconductor encapsulation that gives a cured product having excellent thermal shock resistance and moldability. It relates to a resin composition.

[Technical background of the invention and its problems] In recent years, in the field of semiconductor device encapsulation, along with high integration of semiconductor elements, miniaturization of various functional units on elements and increase in size of element pellets themselves have been required. It is progressing rapidly.
Due to these changes in the element pellets, conventional sealing resins have become unable to 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, when encapsulating a device pellet having a large and fine surface structure using this type of resin composition, phosphosilicate glass (PSG), which is a coating material for protecting the aluminum (Al) pattern on the device pellet surface, is used. ) The film or silicon nitride (SIN) film is cracked or the element pellet is cracked. This tendency is very large especially when a thermal cycle test is carried out. As a result, defective element characteristics due to pellet cracking, and defective Al pattern corrosion due to cracks in the film occur.

As a countermeasure, it is necessary to reduce the stress of the encapsulating resin on the internal inclusions and to increase the adhesion between the encapsulating resin and the PSG film or SiN film on the element with the glass 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, there is a problem in that the use of a large amount of the filler causes a remarkable increase in the viscosity during melting, which impairs the moldability of the resin.

Furthermore, along with changes in these element pellets, a decrease in reliability, which is thought to be caused by the local stress of the resin and filler exerted on the chip, has become a problem, and in order to avoid this, cut coarse particles of crushed filler. Is thought to be effective. Further, when the package is small and thin, the gate of the molding die is smaller than that of a normal one, 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, and unfilling or deformation of the bonding wire may occur. Therefore, attention has been paid to spherical fillers that have small fluid damage and good flowability, but when spherical fillers with a single particle size distribution are used, burrs that occur during molding become significantly longer and the strength increases. It had the drawback of falling.

[Object of the Invention] An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation, which solves the above-mentioned problems and gives a cured product having excellent thermal shock resistance and moldability.

[Summary of the Invention] In order to achieve the above-mentioned object, the present inventors have earnestly studied, and as a result, in a crushed silica powder usually used as a filler, a predetermined amount of a specific spherical silica powder in consideration of a particle size is specified. The inventors have found that the mixed semiconductor encapsulating resin has excellent thermal shock resistance and good moldability, and completed the present invention.

That is, the epoxy resin composition for semiconductor device encapsulation of the present invention comprises: (A) epoxy resin; (B) phenol resin curing agent; (C) curing accelerator; (D) crushed particles having an average particle size of 3 to 100 μm. Silica powder; (E) Spherical silica powder having an average particle size of 1 to 50 μm; and (F) Epoxysilane and pure water, the weight ratio of which is 9:
The surface treatment agent is 1 to 9.95: 0.05 in an amount of 0.1 to 1.5% by weight based on the total amount of the components (D) and (E), and the blending amount of the component (E) is the components (D) and (E). 5 to 90% by volume with respect to the total compounding amount of (D) and (E) and the total amount of (A), (B), (C), (D)
And 50 to 75% by volume with respect to the total amount of (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, novolac type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, and these are used alone or in a mixture of two or more kinds.

The phenol resin curing agent as the component (B) of the present invention may be any one generally known as a curing agent for epoxy resins, and examples thereof include phenol novolac resin and cresol novolac resin. A novolac type phenolic resin having two or more functional hydroxyl groups can be mentioned.

The blending amount of the component (B) is usually 30 to 150 parts by weight with respect to 100 parts by weight of the component (A). If it is less than 30 parts by weight, the curing will be insufficient, and if it exceeds 150 parts by weight, the moisture resistance will be poor. It is preferably 50 to 100 parts by weight.

The curing accelerator that is the component (C) of the present invention may be any one as long as it is known to be used as a curing accelerator when curing an epoxy resin with a phenol resin. Good. Specific examples of the component (C) include imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-methylimidazole; benzyldimethylamine,
Examples include tertiary amine compounds such as trisdimethylaminomethylphenol; organic phosphine compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine, and these are used alone or in a mixture of two or more kinds.

The blending amount of the component (C) is usually 0.01 to 10 parts by weight with respect to 100 parts by weight of the component (A). If it is less than 0.01 parts 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, fusible silica powder, Alternatively, a mixture thereof may be used. When the average particle diameter is 3 μm, the fluidity is poor, and when it exceeds 100 μm, not only various work-related problems such as gate clogging during molding occur but also in the case of a resin-sealed semiconductor element, It may cause malfunction and 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. Examples thereof include silica powder, fused silica powder, and a mixture thereof. When the average particle diameter is out of the above range, the effect of improving fluidity during molding is small.

Further, the components (D) and (E) of the present invention have a maximum particle size of 50
(D) component of less than μm and (E) having an average particle size of 5 to 50 μm
When the component (D) is blended in an amount of 10 to 90% by volume based on the total amount of the components (D) and (E), the composition of the present invention exhibits extremely good moldability. At the same time, the obtained cured product has excellent thermal shock resistance, which is preferable. The components (D) and (E) of the present invention are composed of the component (D) having an average particle diameter of 5 to 100 μm and the average particle diameter of 1 to 30 μm.
When the (E) component is blended in an amount of 5 to 60% by volume based on the total amount of the (D) and (E) components, the resulting cured product has excellent heat resistance. It is preferable because it has impact resistance. The ratio of the particle diameters of the component (D) and the component (E) is preferably 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 90% by volume based on the total amount of the components (D) and (E). If the blending amount is out of the above range, a sufficient effect of improving fluidity cannot be obtained. In addition, the total amount of the above-mentioned (D) and (E) components is 50 to 75 volumes with respect to the total compounding amount of the above-mentioned (A), (B), (C), (D) and (E) components. %.
If the content is less than 50% by volume, the cured product obtained cannot have sufficient thermal shock resistance, and if it exceeds 75% by volume, the melt viscosity increases and the moldability decreases.

The interface treatment agent which is the component (F) of the present invention is a mixture of epoxysilane and pure water, and is a component for further improving the effect of the present invention. Epoxysilane has the general formula: YSi
(OR ₁ ) ₃ (wherein Y represents a monovalent organic group having an epoxy group, R ₁ represents an alkyl group having 1 to 5 carbon atoms), and for example, γ-glycidoxypropyltri Methoxysilane and the like, and pure water refers to pure water such as distilled water and deionized water, especially water that does not contain inorganic or organic ions or ion-generating substances, or has a very small content thereof. .

The interface treatment agent used in the present invention is a mixture of the above-mentioned 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.

The composition of the present invention is produced by melt-kneading the above-mentioned components with a heating roll, melt-kneading with a kneader, melt-kneading with an extruder, mixing with a special mixer such as pulverization, and an appropriate combination of these methods. be able to.

In addition, 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, and polystyrene, if necessary. You may add various thermoplastic resins, such as polymethylmethacrylate, polyvinyl acetate, or these copolymers, silicone oil, silicone rubber, etc.

Hereinafter, the present invention will be described in more detail with reference to Examples of the present invention. In addition, all the compounding ratios in the table represent% by weight unless otherwise specified.

[Examples of the Invention] Examples 1 to 3 The components of the compositions shown in Table 1 were used to obtain compositions of the present invention. First, the above composition in a Henschel mixer,
After the filler was treated with the interfacial treatment agent, the remaining components were put into a mixer, mixed, kneaded with a heating roll at 60 to 110 ° C., cooled, and then pulverized.

In addition, each resin in Table 1 is an ortho-cresol novolac type epoxy resin (epoxy equivalent 196, softening point 76 ° C), flame-retardant epoxy resin (epoxy equivalent 270, softening point 30 ° C),
Phenol novolac resin (phenol equivalent 106, softening point 97 ° C) was used.

Comparative Examples 1 to 6 Each component having the composition shown in Table 2 was treated in the same manner as in the example to give a comparative example.

The following experiments were conducted on the composition components obtained in the above Examples 1 to 3 and Comparative Examples 1 to 6. The results are shown in Tables 3-5.

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 (cooling cycle test at -65 ° C to 150 ° C) was performed to measure defective characteristics.

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

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.

[Effects of the Invention] The epoxy resin composition for semiconductor encapsulation of the present invention is useful as a packaging material for semiconductor electronic components 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. 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 (51) Int.Cl. ⁵ Identification number Internal reference number FI technical display location H01L 23/31 (56) References JP 61-85432 (JP, A) JP 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) Crushed silica powder having an average particle diameter of 3 to 100 μm; (E) Average particle diameter of 1 to 1 Spherical silica powder having 50 μm; and (F) consisting of epoxysilane and pure water, the weight ratio of which is 9:
The surface treatment agent is 1 to 9.95: 0.05 in an amount of 0.1 to 1.5% by weight based on the total amount of the components (D) and (E), and the blending amount of the component (E) is the components (D) and (E). 5 to 90% by volume with respect to the total amount of (D) and (E) and the total amount of (A), (B), (C), (D)
And 50 to 75% by volume with respect to the total compounding amount of (E), an epoxy resin composition for semiconductor encapsulation.