KR100364241B1 - Epoxy resin composition for sealing of semiconductor device - Google Patents

Abstract

PURPOSE: Provided is an epoxy resin composition for sealing semiconductor device which has excellent resistance to corrosion of aluminum pad, and improved moldability at high temperature and humidity. CONSTITUTION: The resin composition essentially comprising an epoxy resin represented by formula 1, a curing agent represented by formula 2, a curing accelerator represented by formula 3, a coupling agent, a modified silicon oil, and an inorganic filler, is characterized in that the coupling agent is a coupling agent mixture of mercapto-based coupling agent and epoxy-based coupling agent in weight ratio of 2:8-6:4, and the amount of the used mixture is 0.2-0.3 wt% based on the total resin composition. In the formulas, n represents a polymerization degree and is a number of 0, 1 or 2.

Description

Epoxy Resin Compositions for Semiconductor Device Sealing

The present invention relates to an epoxy resin composition which is excellent in workability during molding and excellent in reliability such as not causing corrosion of an aluminum pad under high temperature and high humidity conditions. More specifically, Ortho Cresol Novolac) epoxy resin, phenol novolac curing agent, mercapto coupling agent and epoxy coupling agent is a mixed coupling agent consisting of a weight ratio of 2: 8 to 6: 4, triphenylphosphine The present invention relates to an epoxy resin composition for sealing semiconductor elements excellent in moldability and excellent resistance to corrosion of an aluminum pad, including curing accelerators, modified silicone oils, and inorganic fillers as essential components.

In general, a resin sealing semiconductor device has a disadvantage in that a failure frequency due to corrosion of an aluminum pad increases due to thermal stress and moisture permeation according to temperature and humidity changes in an external environment. As a method for suppressing the occurrence of corrosion, the use of a high-purity epoxy resin or a curing agent, the suppression of delamination by the addition of an adhesive hardening agent between the semiconductor element sealant and the lead frame, and the application of an ion trapper There is a method of lowering impurities and decreasing the moisture absorption by high filling of the inorganic filler.

Japan's special office 62-26649 introduces a high-purity olso cresol novolac-type epoxy resin, and since the development of a phenolic resin that can replace the acid anhydride curing agent, the problem of corrosion of aluminum wiring in semiconductor devices has been completely solved. Since the aluminum pad used as the wire is in direct contact with the epoxy resin composition because it must be connected to the gold wire, corrosion is likely to occur, and thus an increase in electrical resistance is caused.

In order to solve this problem, an epoxy resin composition having improved adhesion strength between the epoxy resin composition and the aluminum pad, a low moisture absorption amount, and a low impurity concentration is required. However, a satisfactory resin composition is required due to the characteristics of the semiconductor and the fragility of the epoxy resin composition. Could not be obtained.

The present invention achieves suppression of delamination, which is a peeling phenomenon occurring at the interface between the epoxy resin composition and the lead frame or between the epoxy resin composition and the surface of the semiconductor device by the addition of an adhesion enhancing agent, thereby providing excellent resistance to corrosion of aluminum pads. It is to provide an epoxy resin composition for sealing semiconductor elements excellent in moldability.

The present invention relates to a mercapto-based coupling agent and epoxy with respect to the entire composition consisting of an epoxy resin represented by Formula 1, a curing agent represented by Formula 2, and a triphenyl phosphine curing accelerator represented by Formula 3. It is related with the epoxy resin composition for semiconductor element sealing characterized by adding 0.2-0.3 weight% of the mixed coupling agents which mixed the system coupling agent in the weight ratio 2: 8-6: 4.

That is, the present invention is an epoxy resin that can be represented by the formula (1)

(Where n represents the degree of polymerization and has a value of n = 0, 1, 2)

A curing agent represented by formula (2) and

(Where n represents the degree of polymerization and has a value of n = 0, 1, 2)

Triphenyl phosphine curing accelerator represented by the formula (3)

A mercapto-based coupling agent and an epoxy-based coupling agent relate to an epoxy resin composition for sealing semiconductor elements comprising a mixed coupling agent composed of a weight ratio of 2: 8 to 6: 4, a modified silicone oil, and an inorganic filler as essential components.

Hereinafter, the present invention will be described in detail.

In the present invention, the epoxy resin is an oxo cresol novolac-based epoxy resin, 10 to 15% by weight based on the total composition, and a high purity epoxy having an equivalent weight of 180 to 210 is preferable.

As the curing agent used in the present invention, a conventional phenol novolak resin, cresol novolak resin, dicyclopentadiene resin, etc. having two or more hydroxyl groups and having a hydroxyl group equivalent of 100 to 200, may be used alone or two kinds thereof. The above can be used in parallel. However, from the viewpoint of economy and moldability, it is preferable to use at least 50% by weight of the phenol novolak-type resin, and the composition ratio of the epoxy resin and the curing agent is preferably an epoxy equivalent of 0.8 to 1.2 with respect to the hydroxyl equivalent, and the amount of use is 5.0-10.0 weight% is preferable with respect to the whole composition.

The curing accelerator used in the present invention is a triphenyl phosphine curing accelerator represented by the formula (3) is preferably used 0.2 to 0.3% by weight based on the total composition.

The coupling agent used in the present invention is preferably a mercapto-based and epoxy-based weight ratio of 2: 8 to 6: 4, but when the weight ratio is smaller than 2: 8 or larger than 6: 4, for example, 1: 9, 7: In the case of 3 or 8: 2, etc., the effect of a mercapto type coupling agent becomes weak. The amount of the coupling agent mixture used is 0.2 to 0.3% by weight based on the total epoxy resin composition.

In the present invention, inorganic fillers and other molding materials may be used in addition to the above-described components. The inorganic fillers used are preferably molten silica having an average particle size of 0.1 to 35 μm, and the filling amount is 70 to about the entire composition. Preference is given to using 80% by weight. If the inorganic filler is less than 70% by weight, sufficient strength cannot be realized and moisture can be easily penetrated, which is fatal to aluminum pad corrosion. On the other hand, the upper limit of the inorganic filler is preferably selected in consideration of the moldability, 80% by weight is preferred as in the present invention. In addition, the shape of the inorganic filler is preferably in the form of a mixture of pulverized and spherical silica in the ratio of constituent composition ratio 3: 7 to 7: 3.

The molding materials of the present invention include flame retardants of bromo epoxy, flame retardants such as antimony trioxide, aluminum hydroxide, antimony pentoxide, release agents such as higher fatty acids, higher fatty acid metal salts, ester waxes, colorants such as carbon black, organic and inorganic dyes, and epoxys. Coupling agents, such as a silane, an aminosilane, and an alkylsilane, can be used as needed.

As a general method for producing an epoxy resin composition using the above components, a predetermined amount is uniformly mixed sufficiently using a Henschel mixer or a Rodige mixer, melt-kneaded with a roll mill or a kneader, and cooled and pulverized. The final powder product can be obtained.

As a method of sealing a semiconductor element using the epoxy resin composition obtained in the present invention, a low pressure transfer molding method is most commonly used, or injection molding or casting may be used.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Examples 1-4

In order to prepare the epoxy resin composition for sealing a semiconductor device of the present invention, as shown in Table 1, each component was weighed, and then uniformly mixed using a Henschel mixer to prepare a powdery primary composition. After melt kneading at 100 ° C. for 7 minutes, an epoxy resin composition was prepared by cooling and pulverizing.

The epoxy resin composition thus obtained was measured by thermal flow strength and adhesion strength by UTM by spiral flow and Shore-D measurement. After the test piece was cured at 175 ° C. for 6 hours, the glass transition temperature and moisture absorption rate were measured. Measured. In addition, 20 SOPs were formed and post-cured, and then absorbed for 168 hours under constant temperature and humidity conditions of 85 ° C. and 65% RH. After pretreatment by passing IR reflow three times for 10 seconds at 245 ° C., 121 ° C. and 100 ° C. After absorbing moisture for 168 hours using PCT (Pressure Cooker Test) of% RH, the corrosion condition of aluminum pads and workability were observed to examine the effect of epoxy resin composition on corrosion and formability of aluminum pads. After examining, it is shown in Table 1.

Ingredient Example 1 Example 2 Example 3 Example 4 Epoxy resin 14.66 14.66 14.66 14.66 Phenolic novolac resin 7.94 7.94 7.94 7.94 Curing accelerator 0.24 0.24 0.24 0.24 Coupling Agent Mercapto 0.06 0.08 0.10 0.12 Epoxy 0.20 0.18 0.16 0.14 Silica 74.0 74.0 74.0 74.0 Epoxy modified silicone oil 0.13 0.13 0.13 0.13 Carbon black 0.27 0.27 0.27 0.27 Carnauba Wax 0.25 0.25 0.25 0.25 Other preparation 2.25 2.25 2.25 2.25 Spiral Flow (inch) 36 35 35 32 Thermal strength (Shore-D) 74 75 72 73 Adhesion Strength (kg / ㎠) 30 29 32 33 Glass transition temperature (℃) 144 147 142 144 Formability (Sticking Count) 0/50 0/50 0/50 0/50 Hygroscopicity (168 hours PCT) 0.36 0.34 0.35 0.32 Corrosion occurrence (168 hours PCT) 0/45 0/45 0/45 0/45

(Unit: weight%)

Comparative Examples 1 to 3

As shown in Table 2, each component was weighed to a given composition to prepare an epoxy resin composition in the same manner as in Example, and the measurement of each physical property, the occurrence of corrosion of aluminum pads, and the moldability are shown in Table 2.

Ingredient Comparative Example 1 Comparative Example 2 Comparative Example 3 Epoxy resin 14.66 14.66 14.66 Phenolic novolac resin 7.94 7.94 7.94 Curing accelerator 0.24 0.24 0.24 Coupling Agent Mercapto 0.00 0.26 0.21 Epoxy 0.26 0.00 0.05 Silica 74.0 74.0 74.0 Epoxy modified silicone oil 0.13 0.13 0.13 Carbon black 0.27 0.27 0.27 Carnauba Wax 0.25 0.25 0.25 Other preparation 2.25 2.25 2.25 Spiral Flow (inch) 34 35 32 Thermal strength (Shore-D) 72 75 73 Adhesion Strength (kg / ㎠) 20 35 34 Glass transition temperature (℃) 144 147 144 Formability (Sticking Count) 0/50 16/50 4/50 Hygroscopicity (168 hours PCT) 0.41 0.34 0.32 Corrosion occurrence (168 hours PCT) 5/45 0/45 0/45

(Unit: weight%)

As shown in Comparative Example 1, when the coupling agent is used alone, the moldability is excellent. Relatively small compared to 3, the moisture resistance is low, and the possibility of corrosion of the aluminum pad is increased, and when the mercapto system is used alone as in Comparative Example 2 or the mixing ratio of the mercapto system and the epoxy system is 6 or more as in Comparative Example 3, the epoxy Moisture resistance is improved because the adhesion strength is greater than that of Comparative Example 1 using the system alone, but the moldability is poor during operation, which is a serious problem in actual operation. Therefore, in order to satisfy the moldability and moisture resistance at the same time, as in the case of Examples 1 to 4, by using a mixture of mercapto-based and epoxy-based at the same ratio as in the present invention, the adhesive strength between the resin composition and the lead frame is increased to an appropriate level. It is possible to secure the expected moisture resistance and moldability at the same time.

As described above, when the semiconductor element is sealed using the epoxy resin composition of the present invention, adhesion between the resin composition and the lead frame is greatly improved, and moisture penetration into the semiconductor element is suppressed. A semiconductor device can be obtained. In particular, the effect is more excellent when the material of the lead frame is copper than when alloy 42 (Alloy 42).

Claims (2)

In the composition comprising the epoxy resin represented by the following formula (1), the curing agent represented by the formula (2), the curing accelerator represented by the formula (3), the coupling agent, the silicone-modified oil and the inorganic filler as essential components, the coupling agent Is a mixed coupling agent in which a mercapto-based coupling agent and an epoxy-based coupling agent are mixed in a weight ratio of 2: 8 to 6: 4, and 0.2 to 0.3% by weight is added to the entire resin composition. Epoxy resin composition for semiconductor element sealing. Formula 1

(Where n represents the degree of polymerization and has a value of n = 0, 1, 2) Formula 2

(Where n represents the degree of polymerization and has a value of n = 0, 1, 2) Formula 3

Allocresol novolac epoxy resin: 12 to 15% by weight, Phenol novolak resin curing agent: 7 to 10% by weight, Triphenol phosphine curing agent: 0.2 to 0.3% by weight, Mercapto-based coupling agent / epoxy-based coupling agent weight mixing ratio 2: 8 to 6: 4 mixed coupling agent: 0.2 to 0.3% by weight, Silica inorganic filler: 70-80% by weight and Epoxy modified silicone oil: 0.1 to 0.2% by weight Epoxy resin composition for sealing semiconductor elements composed of.