KR20040059324A - Epoxy Resin Composition for Encapsulating Semiconductor Device - Google Patents

Abstract

PURPOSE: An epoxy resin composition for semiconductor device package is provided, to prevent the generation of crack between a pad face and a chip due to Pb free state in high temperature soldering and to reduce the adhesion of an epoxy packaging material and a wafer chip. CONSTITUTION: The epoxy resin composition comprises an o-cresol novolac epoxy resin of the formula 1; a diglycidyl ether bisphenol modified epoxy resin of the formula 2; a phenol novolac resin; a coupling agent obtained by pretreating the coupling agent represented by SiX3-(CH2)3-O-CH2R (wherein R is a cycloepoxy, amino, methacryl, mercapto or vinyl group, X's are identical or different one another and are a methoxy or ethoxy group) with glycols or distilled water; a coupling agent represented by SiX3-(CH2)3-O-CH2R; a curing accelerator; an inorganic filler; a brominated epoxy resin; antimony trioxide; and other additives. In the formulas 1 and 2, R is OH or CH3, G is a glycidyl group and n is an integer of 0-3; and in the formula 3, R is H or CH3, G is a glycidyl group and n is an integer of 0-3.

Description

Epoxy Resin Composition for Encapsulating Semiconductor Device

The present invention relates to an epoxy resin composition for sealing a semiconductor device, and more particularly, a diglycidyl ether bisphenol-modified epoxy resin and two or more coupling agents, and a high thermal filler, particularly post-semiconductor process by high filling inorganic fillers Semiconductor that maintains high reliability by improving crack problem on pad surface and chip and reducing adhesion problem between epoxy encapsulant and wafer chip during high temperature solder process in Pb free An epoxy resin composition for sealing elements.

Since the epoxy resin composition is adopted as a sealing material for semiconductor sealing, workability and productivity when mounting a semiconductor package on a printer substrate have been remarkably improved with recent advances in surface mounting technology. In addition, since the shortening and thinning of the electronic and electronic parts is accelerated, the demand for low stress, moisture resistance, and high adhesion of the epoxy resin composition is increasing day by day. In addition, due to environmental problems, a solderless process is being developed in a solder process, which is a post-process SOLDER. As a result, the solder process temperature increases from 230 ° C to 265 ° C, resulting in package cracks and wafer and epoxy resin compositions. Since the interfacial peeling phenomenon of the liver is more likely to occur, it is difficult to expect a reliable product with the existing epoxy resin composition.

As described above, a resin-sealed semiconductor in which a large semiconductor device is sealed in a small and thin package has a package crack or an aluminum pad corrosion due to thermal stress caused by changes in temperature and humidity of an external environment in a lead-free process. This increases the frequency of failures. Accordingly, in order to improve crack resistance, there is a demand for lowering the moisture absorption rate, improving the adhesive strength and the high temperature strength. In order to reduce the stress, it is known to control the filler content, to lower the coefficient of thermal expansion, and to achieve low elasticity by adding a modifier.

High filling technology due to low stress is already known, according to this method, the package thermal stress is suppressed. As a method of low elasticity, modification by various rubber components (Japanese Patent Laid-Open No. 63-1894 and Hei 5-291436) has been studied, and an epoxy resin molding material blended and modified with a silicone polymer having excellent thermal stability is widely adopted. have. Since the silicone oil mixed in this method is incompatible with the epoxy resin and the curing agent, which are the base resins of the molding material, the silicone oil is in the form of fine particle dispersion (isolated structure) in the base resin, thereby achieving low elastic modulus while maintaining heat resistance. However, if the solder temperature is raised to 265 ° C in the lead-free process, the package crack is generated due to the decrease in adhesion between the epoxy encapsulant and the lead-on chip and the epoxy encapsulant and the increase in water vapor pressure. It was difficult to obtain this high semiconductor element.

The present invention is to solve the problems of the prior art as described above, by using a mixture of diglycidyl ether bisphenol-modified epoxy resin and two or more types of coupling agent, and high filling inorganic fillers, thermal shock, crack resistance and adhesion It is an object to provide an epoxy resin composition having improved properties.

That is, the present invention is an olso cresol novolac epoxy resin represented by the following general formula (1), a diglycidyl ether bisphenol-modified epoxy resin represented by the following general formula (2), a phenol novolak resin, a coupling agent represented by the following general formula (4) glycols Or a coupling agent pretreated with distilled water, a coupling agent represented by the following formula (4), a curing accelerator, an inorganic filler, a brominated epoxy resin, antimony trioxide, and other additives.

[Formula 1]

In the above formula, R is a hydroxy group or methyl group, G is a glycidyl group, n is an integer of 0 to 3.

[Formula 3]

In the formula, R is a hydrogen atom or a methyl group, G is a glycidyl group, n is an integer of 0 to 3.

[Formula 4]

Wherein R is a cycloepoxy group, an amino group, a methacryl group, a mercapto group, or a vinyl group, X is a methoxy group or an ethoxy group, and the plurality of X's may be different from each other.

The present invention will be described in more detail below.

In the present invention, an oxo cresol noblock resin and a diglycidyl ether bisphenol-modified epoxy resin are mixed and used as the base resin, and a phenol novolac-based curing agent is introduced therein.

In the present invention, the osol cresol noblock resin is used in the range of 3 to 12% by weight based on the total resin composition of the structure represented by the formula (1).

In the above formula, R is a hydroxy group or methyl group, G is a glycidyl group, n is an integer of 0 to 3.

The diglycidyl ether bisphenol-modified epoxy resin of the present invention is represented by the following formula (2).

In the formula, R is a hydrogen atom or a methyl group, G is a glycidyl group, n is an integer of 0 to 3.

The content of the diglycidyl ether bisphenol-modified epoxy resin in the total composition is in the range of 1 to 8% by weight. If the content of diglycidyl ether bisphenol-modified epoxy resin is less than 1% by weight, sufficient adhesive properties and improved reliability cannot be obtained. If the content of diglycidyl ether bisphenol modified epoxy resin is less than 1% by weight, productivity is increased due to flow characteristics and manufacturing process problems. Can't expect

The diglycidyl ether bisphenol-modified epoxy resin may be prepared by mixing epichlorohydrin with a diglycidyl ether bisphenol epoxy monomer of Formula 3 below to proceed with a ring-opening reaction at low temperature.

In the formula, R is a hydrogen atom or a methyl group, G is a glycidyl group, n is an integer of 0 to 3.

The resin thus obtained is a high purity epoxy resin having an epoxy equivalent of 220 to 360. The diglycidyl ether bisphenol-modified epoxy resin exhibits excellent elastic modulus in a linear structure, and has high heat resistance on the cured structure, thereby acting as a low shrinkage rate and preventing cracks.

In the present invention, the curing agent is a phenol novolak resin, which is commonly used, and a resin having a softening point of 80 to 100 ° C and a hydroxy equivalent of 100 to 120, and used in the range of 1.0 to 8.0% by weight.

In the present invention, the equivalent ratio of the epoxy resin and the curing agent is preferably such that the epoxy equivalent to the hydroxyl equivalent is between 0.9 and 1.1.

In the present invention, two or more coupling agents are mixed and used to enhance moldability and adhesion of the epoxy resin composition. Specifically, the pretreatment of the coupling agent represented by the following formula (4) with glycols such as polyethylene glycol, polypropylene glycol, or distilled water or distilled water is used in the range of 0.1 to 2.0% by weight based on the total resin composition, and another coupling agent is used. Is used in the range of 0.01 to 0.1% by weight without undergoing pretreatment of the terminal structure consisting of amine, mercapto and the like having a reactive group.

Wherein R is a cycloepoxy group, an amino group, a methacryl group, a mercapto group, or a vinyl group, X is a methoxy group or an ethoxy group, and the plurality of X's may be different from each other.

By using two or more types of coupling agents as described above in combination with pretreatment, there is an advantage of having a high adhesive strength, and adhesion between the lead frame and the lead-on chip and the epoxy encapsulant even under the high solder temperature of the lead-free process In addition to improving the characteristics and package cracks, excellent results can be obtained in the long-term evaluation test (thermal shock test, press cooker test) evaluated in the semiconductor assembly process.

In the present invention, it is preferable to use an isocyanate type latent curing catalyst to control the curing rate, and specific examples thereof include tetraphenylphosphonium tetra as a triazine isocyanate imidazole compound or triphenylphosphine adduct. Phenyl borate, a triphenyl phosphine tetraphenyl borate, tetraphenyl boron salt, etc. are mentioned. The content of the curing accelerator is used in the range of 0.02 to 0.40% by weight based on the total epoxy resin composition.

When the co-catalyst is used together with the curing accelerator, more excellent curing characteristics can be obtained. Specific examples thereof include benzyldimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol, tri (dimethylaminomethyl) phenol Phosphine-based triphenylphosphine, diphenylphosphine, phenylphosphine and the like. In the case of using a cocatalyst, the content is in the range of 0.02 to 0.25 wt%.

In the present invention, as the inorganic filler, molten or synthetic silica having an average particle size of 0.1 to 35.0 µm is used so as to be in the range of 70 to 90% by weight based on the whole composition. When the amount of the inorganic filler is less than 70% by weight, sufficient strength and low thermal expansion cannot be realized, and moisture permeation becomes easy, and it becomes fatal to reliability characteristics. In addition, when the amount of the inorganic filler exceeds 90% by weight there is a fear that the moldability due to the deterioration of the flow characteristics.

The present invention can provide an epoxy resin composition for sealing semiconductor elements excellent in semiconductor molding properties and reliability by reducing the moisture absorption rate and the coefficient of thermal expansion and improving the mechanical strength by high filling the filler.

In the present invention, in order to impart flame retardance to the epoxy composition, a poly glycidyl ether brominated phenol epoxy having an epoxy equivalent of 250 to 300 and a bromine content of 35 to 40% is mixed with antimony trioxide. Epoxy bromide and antimony trioxide have a problem of accelerating the deterioration of reliability by generating chip corrosion by impurity ions under high temperature, high pressure and high humidity. Therefore, in the present invention, in order to improve the reliability in the range of satisfying the specification of flame retardant UL94 V-O, the content of the two components is 0.2 to 1.2% by weight based on the total composition, respectively.

In the resin composition of the present invention, release agents such as higher fatty acids, natural fatty acids, paraffin waxes, ester waxes, colorants such as carbon black, organic and inorganic dyes, crosslinking enhancers, flame retardant aids, and the like without departing from the object of the present invention, A leveling agent etc. can be used as needed.

The epoxy resin composition of the present invention is uniformly pulverized by mixing a predetermined amount using a Henschel mixer or a Lodige mixer, and then obtained a primary powder product, followed by melt kneading at about 100 minutes using a roll mill or a kneader at about 100 ° C. After cooling and grinding can be prepared.

Hereinafter, one embodiment of the present invention will be described in more detail with reference to the following examples, which are intended for purposes of explanation and are not intended to limit the present invention.

Production Example

1.0 mole of diglycidyl ether bisphenol A (molecular weight 228) and 2.0 mole epiclohydrin were added to a round-necked flask reaction tube, and then 0.02 mole of 2-methylimidazole aqueous solution was slowly added to the flask at a reaction temperature of 130 to 220 ° C. After reacting for 6 hours under nitrogen atmosphere while cooling to 10 ° C. or less, 50% sodium hydroxide solution was added thereto. At this time, the temperature was kept below 10 ℃ and reacted for about 4 hours. The mixture thus obtained was added with a mixture of methanol and water, and purified through strong stirring. A diglycidyl ether bisphenol-modified epoxy resin having an equivalent weight of 300 was prepared through a drying process.

Example

Using the diglycidyl ether bisphenol A modified resin prepared above as shown in Table 1 and Table 2 and uniformly pulverized and mixed using a Henschel mixer to obtain a primary powder product, using a roll mill 100 After melt-kneading at about 10 minutes within ℃, through the cooling, grinding process to prepare an epoxy encapsulation composition.

The physical properties and the reliability of the epoxy resin composition thus obtained were evaluated and shown in Tables 3 and 4.

1) Japanese Gunpowder: EOCN-1020-65

2) Production Example

3) Japanese Gunpowder: Bren-S

4) 2,4-diamino-6- (2-2-methyl-1-imidazole) ethyl-1,3,5-triazine

5) A-187 and Polypropylene Glycol Pretreatment Products

6) γ-mercapto propylene trimethoxysilane

7) Meiwa HF-1,3 Phenolic Noble Type Resin

[Property evaluation method]

럴 Spiral Flow

Mold was manufactured based on EMMI standard to evaluate flow length at molding temperature (175 ℃) and molding pressure of 70Kgf / cm ² .

㉡ glass transition temperature (Tg)

Evaluated by TMA (Thermal mechanical Analyser) (Raising temperature 10 ℃ / min)

㉢ adhesion

Tensile force between Cu Lead Frame and epoxy encapsulant is measured using UTM

㉣ flame retardant

UL 94 vertical test, based on 1/16 inch, 5 tests of sparking flame for 10 seconds after sparking off

1st and 2nd combustion time Sum of secondary combustion time and glow time for each specimen Total time of primary and secondary combustion time of 5 specimens V-O Within 10 seconds Within 30 seconds Within 50 seconds V-1 Within 30 seconds Within 60 seconds Within 250 seconds V-2 Within 30 seconds Within 60 seconds Within 250 seconds

[Property evaluation method]

㉠ Crack evaluation

After molding for 90 seconds at 175 ℃ using MPS (Multi Plunger System) molding machine, after curing for 4 hours at 175 ℃ and then proceeding three times with IR REFLOW temperature as 265 ℃, it was cracked using ultrasonic (C-SAM) facility. The number of occurrences as C-SAM

㉡ Peelability evaluation

In the Thermal Shock Tester, C-SAM was used to perform a thorough test at 100, 200, and 250 cycles from 165 ° C to -50 ° C, respectively, in which 10% or more peeling occurred between the leadframe, the lead-on chip and the epoxy encapsulant. evaluation

㉢ Moldability evaluation

The moldability evaluation items are voids corresponding to appearance defects. Observation of appearance defects in gates, air bends, and appearances is greatly observed. Evaluated.

As shown in Table 3 and Table 4 it can be seen that the adhesion properties of the lead-on chip, the lead frame and the epoxy encapsulation material is significantly improved, and shows excellent characteristics in terms of reliability.

According to the present invention, it is possible to provide an epoxy resin composition for forming a semiconductor device having excellent reliability even after a lead-free process by improving thermal shock, crack resistance, and adhesion of the epoxy resin composition.

Claims (4)

An olso cresol novolac epoxy resin represented by the following formula (1), a diglycidyl ether bisphenol-modified epoxy resin represented by the following formula (2), a phenol novolak resin, and a coupling agent represented by the following formula (4) are pretreated with glycols or distilled water. Epoxy resin composition for sealing a semiconductor device comprising a coupling agent, a coupling agent represented by the following formula (4), a curing accelerator, an inorganic filler, a brominated epoxy resin, antimony trioxide and other additives. [Formula 1] In the above formula, R is a hydroxy group or methyl group, G is a glycidyl group, n is an integer of 0 to 3. [Formula 3] In the formula, R is a hydrogen atom or a methyl group, G is a glycidyl group, n is an integer of 0 to 3. [Formula 4] Wherein R is a cycloepoxy group, an amino group, a methacryl group, a mercapto group, or a vinyl group, X is a methoxy group or an ethoxy group, and the plurality of X's may be different from each other. According to claim 1, wherein the content of the oligocresol novolac epoxy resin in the composition is 3 to 12% by weight, the content of diglycidyl ether bisphenol-modified epoxy resin is 1 to 8% by weight, the content of phenol novolac resin 1.0 to 8.0% by weight, 0.1 to 2.0% by weight of the pretreated coupling agent, 0.01 to 0.1% by weight of the untreated coupling agent, 0.02 to 0.4% by weight of the curing accelerator, and inorganic Epoxy for semiconductor device sealing, characterized in that the content of the filler is 70 to 90% by weight, 0.2 to 1.2% by weight epoxy bromide resin, 0.2 to 1.2% by weight antimony trioxide, and 0.3 to 0.8% by weight of other additives Resin composition. 2. The epoxy for semiconductor element sealing according to claim 1, wherein an isocyanate type latent curing catalyst is used as the curing accelerator, and an amine or phosphine type cocatalyst is further used in a range of 0.02 to 0.25 wt%. Resin composition. The epoxy resin composition for sealing a semiconductor device according to claim 1, wherein the epoxy equivalent of the brominated epoxy resin is 250 to 300 and has a bromine content of 35 to 40%.