KR20000038717A - Epoxy resin composition for sealing semiconductor device - Google Patents

Abstract

PURPOSE: An epoxy resin composition is provided which improves adhesion, crack-resistance about the lead frame and the lead on chip, and a mechanical strength. The resin decreases absorption rate, thermal expansion coefficient. CONSTITUTION: An epoxy resin composition comprises 3.0-12.0 wt% of o-cresol novolak epoxy resin or biphenyl epoxy resin having an epoxy equivalent of 170-250 such as diglycidyl ether bisphenol A, 0.1-5.0 wt% of modified-silicon epoxy resin(formula 3), 2.0-6.5 wt% of a curing agent such as, phenol novolak resin, cresol novolak resin, and xylok, 0.01-0.30 wt% of a potential cure-accelerating agent, such as tetraphenyl phosphonium tetraphenyl borate, dicyan diamide and 82-89 wt% of an inorganic filler such as melting or synthetic silica having an average particle size of 0.1-35.0 micrometer. In the formula, G is glycidyl, R1 being identical or different is methyl, phenyl, X is reactive organic group, Y is cresol or phenol, and n is an integer of 5-100.

Description

Epoxy Resin Compositions for Semiconductor Device Sealing

The present invention relates to an epoxy resin composition for sealing semiconductor devices, and more particularly, to thermal shock by adding silicone-modified epoxy resins and latent curing accelerators in addition to epoxy resins, curing agents, curing accelerators, inorganic fillers and additives, and high-filling inorganic fillers. The present invention relates to an epoxy resin composition for semiconductor device encapsulation, which can solve an adhesion problem occurring between a wafer chip and an epoxy encapsulant according to a change, and has excellent reliability and molding characteristics.

In recent years, the degree of integration of semiconductor devices is improving day by day, and thus, the size of wiring devices, the size of cells, and the number of multilayer wirings are rapidly progressing. On the other hand, packages that protect semiconductor devices from the external environment have been accelerated in size and thickness in terms of high-density mounting to a printed board, that is, surface mounting.

In particular, in resin-sealed semiconductor devices in which large semiconductor devices are sealed in small and thin packages, the frequency of failure due to thermal stress caused by changes in temperature and humidity of the external environment, or cracks in aluminum pads is increased. do. Accordingly, there is a demand for a highly reliable semiconductor encapsulant through crack resistance and low stress of the epoxy resin material for sealing.

Examples of methods for solving the above demands include a method of lowering the moisture absorption rate to improve crack resistance and improving adhesion strength and high temperature strength, a method of high filling by adjusting fillers for low stress, and a coefficient of thermal expansion. The method of lowering the amount and the method of achieving a low elasticity by adding a modifier are known.

In order to achieve low elasticity by adding a double modifier, modification by various rubber components (Japanese Patent Laid-Open No. 63-1894, Japanese Patent Laid-Open No. 5-291436) has been studied, and a silicone polymer having excellent thermal stability is blended and modified. Epoxy resin molding materials are widely adopted. According to this method, since the silicone oil used as a plasticizer is incompatible with the epoxy resin and the curing agent which are the base resins of the molding material, it is in the form of fine particle dispersion (sea island structure) in the base resin, thereby achieving low elastic modulus while maintaining heat resistance. However, this method has been difficult to obtain a highly reliable semiconductor device due to the problems caused by a decrease in adhesion between the lead frame and the lead-on chip and the epoxy encapsulant and poor moldability due to the introduction of a modifier.

An object of the present invention is to solve the above problems, by adding a silicone-modified epoxy resin of the modified form of the silicone oil added as a plasticizer to the allocresol novolac or biphenyl-based epoxy further lead frame and lead Improved adhesion between on-chip and epoxy encapsulant to improve peeling and solved moldability defects due to the compatibility of modifiers. High filling of inorganic filler reduces moisture absorption and thermal expansion coefficient and improves mechanical strength. It is to provide an epoxy resin composition for semiconductor element sealing that can suppress the generation of voids generated during semiconductor element molding.

That is, the present invention is an epoxy resin composition consisting of an epoxy resin, a curing agent, a curing accelerator, an inorganic filler and an additive, wherein the epoxy resin is a silicone represented by Chemical Formula 3 in addition to an allocresol novolak epoxy resin and a biphenyl epoxy resin. Modified epoxy resin is further added 0.1 to 5.0% by weight based on the total composition, 0.01 to 0.3% by weight of the latent curing accelerator is added together with the curing accelerator, the content of the inorganic filler is 82 to 89% by weight It relates to an epoxy resin composition for sealing semiconductor elements.

Hereinafter, the present invention will be described in more detail.

Epoxy resins used in the present invention can be roughly divided into two types: first, an allocresol novolac epoxy resin represented by Formula 1 and a biphenyl epoxy resin represented by Formula 2.

R is a methyl group or a hydroxyl group, G is a glycidyl group.

Olsocresol norolak-based epoxy resins and biphenyl-based epoxy resins of the general formulas (1) and (2) are epoxy resins having an epoxy equivalent of 170 to 250, and have a softening point in the range of 40 to 80 ° C. A, diglycidyl ether bisphenol F, allocresol novolac, biphenyl, dicyclopentadiene, naphthalene can be selected from one type or a mixture of two or more types, and the amount of use is preferably 3.0 to 12.0% by weight. .

In addition to the epoxy resin described above, the epoxy resin used in the present invention may be represented by the following Chemical Formula 3 as a silicone-modified epoxy resin, and has a structure having a reactive organic group and a polysiloxane group in an internal structure. The amount of the silicone-modified epoxy resin is preferably used in an amount of 0.1 to 5.0% by weight based on the total composition. When the amount is less than 0.1% by weight, the desired adhesion characteristics between the lead frame and the lead-on chip and the epoxy encapsulant cannot be obtained. When it exceeds weight%, moldability deteriorates due to a decrease in fluidity due to reactivity.

Here, G is a glycidyl group, R ₁ is the same or different methyl group or phenyl group, X is a reactive organic group, Y is cresol or phenol, biphenyl bisphenol, n is an integer of 5 to 100.

The polysiloxane used for the silicone-modified epoxy resin has a molecular weight of 500 to 10,000, preferably 1,000 to 4,000. In addition, as the polysiloxane organic group, an organic group having a reactivity such as an amino group or a mercapto group is possible, and the substitution position is preferably terminal type, side chain type, or side chain terminal type in the polysiloxane.

Epoxy resins used in the production of copolymers (adducts) of silicone modified epoxy prepolymers include diglycidyl ether bisphenol A, diglycidyl ether bisphenol F, cycloaliphatic epoxy, cresol novolac epoxy, and biphenyl type. And dicyclopentadiene-based or naphthalene-based epoxy, and may be used alone or in combination of two or more.

As the curing agent used in the present invention, a phenol novolak resin, a cresol novolak resin, a xylok resin, a dicyclopentadiene resin, etc. having two or more hydroxyl groups and having a hydroxyl equivalent of 100 to 200 may be used. These may be used alone or in combination of two or more. The equivalent ratio of the epoxy resin and the curing agent is preferably in the range of 0.9 to 1.1 epoxy equivalents relative to the hydroxyl equivalent, and the amount of the curing agent is preferably 2.0 to 6.5% by weight based on the total composition.

In the present invention, the latent curing accelerator used in combination with the curing accelerator may be dicyandiamide or tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, Triphenylphosphine adducts such as tetraphenylboron salt and the like can be used, and the amount of use is preferably 0.01 to 0.30% by weight based on the total epoxy resin composition. In addition to the latent curing accelerators, the curing accelerators capable of improving curing characteristics are amine-based benzyldimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol, tri (dimethylaminomethyl) phenol and 2-methylimidazole, 2 -Imidazoles such as -phenylimidazole, organic phosphines such as triphenylphosphine, diphenylphosphine, phenylphosphine and the like can be used in combination of one or two or more.

As the inorganic filler used in the present invention, it is preferable to use fused or synthetic silica having an average particle of 0.01 to 35.0 µm, and the amount of the filler is preferably 82 to 89% by weight based on the total composition. If the inorganic filler is less than 82% by weight, sufficient strength and low thermal expansion cannot be realized, and moisture permeation is easy, which is fatal to the reliability characteristics. If the inorganic filler exceeds 89% by weight, the moldability may be deteriorated due to the deterioration of the flow characteristics. It is not desirable.

In addition, additives commonly used in molding may be included. For example, higher fatty acids, natural fatty acids, colorants such as ester waxes or carbon blacks, organic and inorganic dyes, crosslinking enhancers, flame retardant aids, and leveling agents 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.

Preparation Example 1

1200 g of a biphenyl-based epoxy resin (softening point 65 ° C.) having an equivalent weight of two or more oxirane groups in one molecule is placed in a round-necked flask reaction tube and stirred while sufficiently melting at a temperature of 90 to 110 ° C. The polysiloxane silicone dimethyl 3-gamma amino propyl resin and 250 g of polysiloxane resin substituted with an amino group were introduced into a sock end having a molecular weight of 1,000 to 4,000 by a dropping funnel, and the reaction temperature was 140 to 180 캜 and the stirring speed was 2,000 rpm or more. The reaction was carried out for 2 hours. The viscosity of the silicone modified epoxy resin obtained by such a method was 3-6 poises (con plate viscometer).

Preparation Example 2

300 g of bisphenol F-type high-purity epoxy resins having 160 to 180 epoxy equivalents having two or more oxirane groups in one molecule, and 850 g of cresol novolac epoxy (equivalent to 190 to 210) were placed in a round four-necked flask reaction tube at a temperature of 90 to 110 ° C. It is stirred while melting sufficiently. Herein, 200 g of polysiloxane resin substituted with mercapto group was added to a sock end having a polysiloxane silicone diphenyl mercapto propyl resin molecular weight of 2,000 to 5,000, using a dropping funnel to obtain a desired silicone-modified epoxy product. It was 2-4 poise.

Examples 1-4, Comparative Examples 1-4

After mixing the remaining ingredients in the silicone-modified epoxy resin prepared as shown in Tables 1 and 2, uniformly pulverized and mixed using a Henschel mixer or a Rodige mixer, and then obtained a primary powder product roll mill or kneader Epoxy resin composition was prepared by melt kneading within about 10 minutes at 100 ° C., followed by cooling and grinding. In particular, in order to impart flame retardancy to the epoxy resin composition, 0.5 to 2.0% by weight of polyglycidyl ether brominated phenol epoxy having an epoxy equivalent of 280 to 290 and a bromine content of 35 to 38% was used.

The general physical properties of the prepared epoxy resin composition was evaluated and shown in Table 3, and the reliability evaluation is shown in Table 4.

The prepared epoxy resin composition was evaluated for physical properties and reliability by the following method, and in the case of SOP (Small Outline Package) type semiconductor device and molding, the MPS (Multi Plunger System) molding machine was used at 60 ° C at 175 ° C. After molding for a second time, the peeling between the lead frame and the lead-on chip and the epoxy encapsulant was measured by using an ultrasonic apparatus (SAT), and after curing at 175 ° C. for 6 hours, the thermal shock test was conducted to evaluate the result. .

Ingredient Example 1 Example 2 Example 3 Example 4 Epoxy resin ¹⁾ Allsocresol novolac resin ²⁾ Silicone modified epoxy duct ³⁾ Silicone modified epoxy duct ⁴⁾ Biphenyl epoxy resin 2.51.5-4.5 -3.0-4.2 7.2-0.81.8 6.5-2.6- ⁵⁾ Brominated epoxy resin 1.03 1.00 1.00 1.00 Antimony trioxide 0.33 0.30 0.33 0.33 Phenolic novolac resin 4.20 3.59 4.96 4.63 Triphenylphosphine 0.05 0.09 0.06 0.10 ⁶⁾ latent curing accelerator 0.12 0.07 0.10 0.07 Inorganic filler 85 87 83 84 ⁷⁾ γ-glycithoxypropyltrimethoxysilane 0.42 0.40 0.40 0.42 Carbon black 0.20 0.20 0.20 0.20 Carnauba Wax 0.15 0.15 0.15 0.15

(weight%)

¹⁾ Kayaku Japan (Nippon kayaku): EOCN 1020-55

²⁾ Silicone modified epoxy adduct: Preparation Example 1 (amino group)

³⁾ Silicone modified epoxy adduct: Preparation Example 2 (mercapto group)

⁴⁾ Yucca shell (Yuka shell): YX-4000 H

⁵⁾ Nippon kayaku: Bren-s

⁶⁾ Ajimoto: PN-23

⁷⁾ UCC: Silane A-187

Ingredient Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Epoxy resin ¹⁾ Allsocresol novolac resin ²⁾ Silicone modified epoxy duct ³⁾ Biphenyl epoxy resin 3.5-6.5 3.55.5- 7.85-- 5.0-3.8 ⁴⁾ epoxy bromide 1.00 1.00 1.00 1.00 Antimony trioxide 0.33 0.30 0.33 0.33 Phenolic novolac resin 4.27 3.80 4.22 4.09 Triphenylphosphine 0.15 0.15 0.15 0.15 ⁵⁾ epoxy silicone oil 0.5 1.0 - - ⁶⁾ Polybutadiene Rubber - - 0.7 1.2 Inorganic filler 83 84 85 83.5 ⁷⁾ γ-glycithoxypropyltrimethoxysilane 0.40 0.40 0.40 0.40 Carbon black 0.20 0.20 0.20 0.20 Carnauba Wax 0.15 0.15 0.15 0.15

(weight%)

¹⁾ Kayaku Japan (Nippon kayaku): EOCN 1020-55

²⁾ Silicone modified epoxy adduct: Preparation Example 1 (amino)

³⁾ Yucca shell (Yuka shell): YX-4000 H

⁴⁾ Nippon kayaku: Bren-s

⁵⁾ Toray Dow: TSL-8331

⁶⁾ Japan Synthetic Rubber: Meta Bren

⁷⁾ UCC: Silane A-187

Evaluation item Example Comparative example One 2 3 4 One 2 3 4 Spiral Flow (inch) 33 31 30 27 37 18 36 32 Glass transition temperature (℃) 157 152 158 153 145 143 152 145 Coefficient of thermal expansion α (㎛ / m, ℃) 11.4 10.8 11.8 11.8 12.2 11.9 11.5 12.2 Hot hardness 64 56 67 59 74 52 84 79 Adhesive force (kgf) 87 94 82 88 47 405 45 42 Flexural strength (kgf / ㎜) 15.8 15.2 16.2 14.9 16.5 14.1 14.3 13.6 Flexural modulus (kgf / mm) 2150 2350 2100 2300 1650 1950 2050 2250

Assessment Methods

Spiral Flow (Spiral Flow): Mold was manufactured based on EMMI standard and measured by measuring the flow length at molding temperature (175 ℃) and molding pressure 70kgf / ㎠.

Hot Hardness: Hardness was measured after molding at 175 ℃ for 90 seconds using Showa D boundary. Glass transition temperature (Tg), thermal expansion coefficient: TMA (Thermomechanical Analyser) was evaluated (heating rate 10 ℃ / min)

Adhesion: The tensile strength between the lead frame (Aloy 44) and the epoxy encapsulant was measured and evaluated (using UTM).

Flexural strength and flexural modulus: evaluated according to ASTM D190 using UTM (Universal Test Machine).

Evaluation item Example Comparative example One 2 3 4 One 2 3 4 Peeling Evaluation Preconditioning Exhibition 0/128 0/128 0/128 0/128 8/128 0/128 20/128 11/128 After precondition 1/128 0/128 2/128 0/128 56/128 0/128 128/128 128/128 Crack resistance Number of cracks / number of test devices 0/64 0/64 0/64 0/64 5/64 0/64 7/64 4/64

Assessment Methods

Peeling evaluation: The number of semiconductor devices generated at the interface between the wafer chip (LOC: lead-on chip) and the epoxy encapsulant was evaluated. : SAT facility

Crack resistance: After preconditioning, the thermal shock environment tester (Temperature Cycle Test) was evaluated for cracking by SAT (Scanning Acoustic Tomograph) after 1,000 cycles of curing.

a) Preconditions

The semiconductor device prepared from the epoxy resin composition was dried at 125 ° C. for 24 hours, and then subjected to 5 cycles of thermal shock test, and then left for 168 hours under 85 ° C./85% relative humidity. IR reflow was performed at 235 ° C. for 10 seconds. After passing through three times, the presence of package cracks and peeling were evaluated primarily under precondition conditions.

b) cold shock test

1,000 cycles are carried out with 1 cycle of leaving the semiconductor package at -65 for 10 minutes, 25 ° C for 5 minutes, and 150 ° C for 10 minutes.

As shown in the evaluation of physical properties and reliability of Table 3 and Table 4, the adhesion properties between the lead-on chip, the lead frame and the epoxy encapsulation material were significantly improved, and the characteristics were excellent in terms of reliability.

As described above, the epoxy resin composition according to the present invention solves the compatibility problem caused by the use of silicon alone, thereby improving the adhesive properties and crack resistance between the lead frame, the lead-on chip and the epoxy encapsulant, and at the same time filling the inorganic filler with high filling. It is possible to reduce the moisture absorption rate and the coefficient of thermal expansion and to improve the mechanical strength.

Claims (3)

In the epoxy resin composition consisting of an epoxy resin, a curing agent, a curing accelerator, an inorganic filler and an additive, the epoxy resin is a silicone-modified epoxy resin represented by the general formula (3) in addition to the allocresol novolac epoxy resin and biphenyl epoxy resin. 0.1 to 5.0% by weight of the composition is further added, and 0.01 to 0.3% by weight of the latent curing accelerator is added together with the curing accelerator, and the content of the inorganic filler is 82 to 89% by weight. Epoxy resin composition. Formula 3 Wherein G is a glycidyl group, R 1 is the same or different methyl group or phenyl group, X is a reactive organic group, Y is cresol or phenol, biphenyl bisphenol, and n is an integer of 5 to 100. The method of claim 1, wherein the latent curing accelerator is selected from triphenylphosphine adducts such as tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, tetraphenylboron salt or dicyandiamide type catalysts. Epoxy resin composition for sealing semiconductor elements. Allocresol novolac epoxy resin or Biphenyl epoxy resin 3.0 to 12.0 wt% 0.1 to 5.0% by weight of the silicone-modified epoxy resin of Chemical Formula 3 0.1 to 0.5% by weight of antimony trioxide Brominated Epoxy 0.5-2.0 wt% Curing agent 2.0 to 6.5% by weight 0.01 to 0.3% by weight curing accelerator 0.01 to 0.3 wt% of latent curing accelerator Inorganic fillers 82 to 89% by weight 0.5 to 1 wt% of other additives Epoxy resin composition for sealing a semiconductor device, characterized in that consisting of.