KR100739363B1 - Epoxy resin for packaging semiconductor device - Google Patents

Abstract

The present invention relates to an epoxy resin composition for a semiconductor encapsulant having good bending property and reflow-resistant property and excellent moldability, and includes an epoxy resin, a curing agent, a non-halogen-based flame retardant, and an inorganic filler. Epoxy resin composition comprising a modified epoxy resin produced by glycidyl etherification of a mixture of a phenolic compound having a novolak structure and a 4,4'-dihydroxy biphenyl containing a biphenyl derivative in a molecule as an epoxy resin. 0.5 to 15 weight percent; 2 to 10.5% by weight of a mixture of a polyaromatic curing agent and a polyfunctional curing agent as a curing agent; It is characterized in that the inorganic filler comprises 80 to 93% by weight of the spherical silica having a sphericity of 0.85 or more while the weight ratio of particles having a size of 53㎛ or more and less than 0.3% by weight.

Epoxy resins, biphenyl derivatives, novolac structures, glycidyl etherifications, modified epoxy resins, inorganic fillers

Description

Epoxy resin composition for semiconductor device sealing

The present invention relates to an epoxy resin composition for sealing a semiconductor device, and more particularly, has excellent flame retardancy without containing a halogen flame retardant, good bending property and reflow-resistant property, and moldability even in a thin package. It is related with this excellent epoxy resin composition for semiconductor sealing materials.

Surface-mounted BGA (Ball Grid Array) type package, which has recently attracted attention, has a problem that the package is easily bent due to the asymmetry of the coefficient of thermal expansion due to the single-sided packaging structure. Similarly, new packages such as BOC (Board On Chip) and MCP (Multi Chip Package) are required to improve the bending characteristics due to the asymmetry of the vertical structure. In particular, in new packages such as BOC and MCP packages, the portion occupied by the encapsulant may be thinned to about 100 microns, which causes frequent molding defects such as porosity or incomplete molding when the package is sealed. In addition, due to the recent increase in environmental concern, a welding method in which lead-free welding has been applied to mounting of a semiconductor package has been applied, and most of the welding available in the semiconductor package field has been compared to conventional welding containing lead. Because of the high melting point, the reflow temperature is significantly higher. This causes a problem that the reliability of the package (package) is deteriorated, so the improvement of downflow that can prevent this is required.

SUMMARY OF THE INVENTION An object of the present invention is to improve the bending of an asymmetric single-sided packaging structure while maintaining excellent downflow without using halogen-based flame retardants and phosphorus-based flame retardants, and to exhibit excellent moldability in thin packages such as BOC and MCP as well as BGA packages. It is providing the epoxy resin composition for sealing materials.

According to the present invention, an epoxy resin composition comprising an epoxy resin, a curing agent, and an inorganic filler, which is represented by the phenolic compound having a binovolak structure containing a biphenyl group in a molecule represented by the following general formula (1) as an epoxy resin and the following general formula (2) 0.5 to 15% by weight of a modified epoxy resin produced by glycidyl etherification of a mixture of 4,4'-dihydroxy biphenyl; 2 to 10.5% by weight of a mixture of the polyaromatic curing agent represented by the following formula (3) and the polyfunctional curing agent represented by the formula (4) as the curing agent; Provided is an epoxy resin composition for sealing a semiconductor device comprising 80 to 93% by weight of fused silica, synthetic silica or a mixture thereof as an inorganic filler.

[Formula 1]

(mean value of n is 1 to 6)

[Formula 2]

[Formula 3]

(mean value of n is 1 to 6)

[Formula 4]

 (mean value of n is 1 to 6)

The multi-aromatic curing agent having the structure of Formula 3 and the multifunctional curing agent having the structure of Formula 4 is characterized in that the mixture in a weight ratio of 20:80 to 60:40.

The inorganic filler has an average particle size of 8.7 to 14.9 μm, and a particle size distribution of particles having a cumulative weight ratio of 3 μm or less, 15.4 to 23.4 wt%, a cumulative weight ratio of 24 μm or less, 66.9 to 84.3 wt%, and 53 μm or more. Weight ratio of It is 0.3 weight% or less, It is characterized by the average sphericity degree 0.85 or more.

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

The epoxy resin composition for sealing a semiconductor device of the present invention is characterized by comprising 1) an epoxy resin, 2) a curing agent and 3) inorganic fillers.

In the present invention, the epoxy resin of 1) is a phenolic compound having a novolac structure containing a biphenyl group in a molecule represented by the following formula (1) and 4,4'-dihydroxy biphenyl represented by the following formula (2) A polyaromatic modified epoxy resin produced by glycidyl etherification of a mixture of (dihydroxy biphenyl) (hereinafter phenol mixture) is used.

[Formula 1]

(mean value of n is 1 to 6)

[Formula 2]

Since the polyaromatic modified epoxy resin which is component 1) used by this invention has a structure containing biphenyl in the middle based on a phenol skeleton, it is excellent in hygroscopicity, toughness, and oxidation resistance, and also excellent in crack resistance. . The modified multi-aromatic epoxy resin applied in the present invention has a low crosslinking density to form a carbon layer (char) during combustion at high temperature to ensure flame retardancy. The amount of the polyaromatic epoxy resin applied in the present invention is suitable for 0.5 to 15% by weight of the total resin composition.

As the curing agent of component 2) used in the present invention, a mixture of a polyaromatic curing agent having a structure such as the following Chemical Formula 3 and a polyfunctional curing agent having a structure such as the following Chemical Formula 4 is used, and the mixing ratio is 20:80 to 60:40. Weight percent is preferred. When the multi-aromatic curing agent is less than 20% by weight, it is difficult to secure flame retardant properties, and when it exceeds 60% by weight, the glass transition temperature (Tg) may be lowered to make it difficult to secure the bending property.

[Formula 3]

(average of n is 1 to 6)

[Formula 4]

 (mean value of n is 1 to 6)

The multi-aromatic curing agent of Formula 3 is to react with the multi-aromatic modified epoxy resin to form a carbon layer (char) to achieve flame retardancy by blocking the transfer of heat and oxygen around. As for the usage-amount of a hardening | curing agent, 2-10.5 weight% of the whole resin composition is suitable.

Inorganic filler, component 3) used in the present invention, is fused silica, synthetic silica, or a mixture thereof, having an average particle size of 8.7 to 14.9 µm and a cumulative weight ratio of 3 µm or less, having a cumulative weight ratio of 15.4 to 23.4 weight percent, 24 It is preferable that the cumulative weight ratio of not more than 6 mu m is 66.9 to 84.3 wt%, and the weight ratio of particles having a size of 53 mu m or more is 0.3 wt% or less and the average sphericity is 0.85 or more. If the amount of particles larger than 53㎛ exceeds 0.3% by weight or the average sphericity is less than 0.85, the characteristics of the thin package having a narrow gap may cause pores or incomplete filling during molding, which may adversely affect the formability. .

 The filling amount is used as the remaining amount other than the above-mentioned components with respect to the whole composition, and preferably 80 to 93% by weight. When the inorganic filler is used in less than 80% by weight, there may be a problem in that it is impossible to realize sufficient strength and low thermal expansion, and also there may be a problem in which moisture is easily penetrated and becomes fatal in reliability characteristics. In addition, when the amount of the inorganic filler exceeds 93% by weight, there may be a problem in that moldability is deteriorated due to the deterioration of the flow characteristics.

In the present invention, a curing accelerator may be further used, and the curing accelerator is a component necessary for promoting the curing reaction of the components 1) and 2). For example, benzyldimethyl amine, triethanolamine, triethylenediamine, and dimethylaminoethanol. , Tertiary amines such as tri (dimethylaminomethyl) phenol, imidazoles such as 2-methylimidazole and 2-phenylimidazole, organic phosphines such as triphenylphosphine, diphenylphosphine and phenylphosphine Tetraphenylboron salts such as pins, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, and the like, and one or two or more of them may be used in combination, and the amount of use thereof is 0.1 based on the total epoxy resin composition. To 0.3 wt% is preferred.

In the present invention, a modified silicone oil may be further used. The modified silicone oil may be a silicone polymer having excellent heat resistance, and a silicone oil having an epoxy functional group, a silicone oil having an amine functional group, and a silicone oil having a carboxyl functional group. Species or two or more kinds may be used in an amount of 0.5 to 1.5 wt% based on the total epoxy resin composition. However, when the silicon oil is used in excess of 1.5% by weight or more, there may be a problem in that surface contamination occurs easily and the resin bleed becomes long, and when used in less than 0.5% by weight, sufficient low modulus of elasticity may not be obtained. There may be.

In the molding material of the present invention, release agents such as higher fatty acids, higher fatty acid metal salts, ester waxes, colorants such as carbon black and inorganic dyes, coupling agents such as epoxy silanes, amino silanes, alkyl silanes, and the like may be used. Can be used.

As a general method for producing an epoxy resin composition using the raw materials as described above, a predetermined amount is uniformly mixed sufficiently using a Henschel mixer or a Rodige mixer, followed by melt kneading with a roll mill or a kneader, and cooling and pulverizing. A method of obtaining the final powder product is used.

As a method of sealing a semiconductor element using the epoxy resin composition obtained by this invention, the low pressure transfer molding method is the most commonly used method, It can also be shape | molded by the methods, such as injection molding method and casting.

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

[Examples 1-3]

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 evaluated for physical properties and reliability by the following method, and after molding for 70 seconds at 175 ℃ using a Multi-Plunger System (MPS) molding machine for a reliability test, after 2 hours at 175 ℃ It hardened | cured and the BOC type semiconductor element was produced.

Physical properties and moldability, warpage characteristics, and reliability test results of the epoxy resin composition according to the present invention are shown in Table 2 below.

Reliability test was expressed by the degree of package crack in thermal shock test and the degree of failure of electrical characteristics after PCT (Pressure Cooker Test) absorption.

* Property evaluation method

1) Spiral Flow

Molds were manufactured based on the EMMI standard, and the flow length was evaluated at a molding temperature of 175 ° C. and a molding pressure of 70 Kgf / cm 2.

2) Glass transition temperature (Tg)

It was evaluated by TMA (Thermomechanical Analyser).

3) coefficient of thermal expansion (α1)

Evaluation was made by ASTM D696.

4) Electrical Conductivity

The cured EMC test piece was ground in a grinder to a particle size of about # 100 to # 400 mesh (MESH), weighed 2g ± 0.2mg of the powdered sample, and put into 80 ml of distilled water. After extraction, the electrical conductivity was measured using the supernatant of the extract water.

5) Flame retardant

It evaluated according to UL 94 V-0 standard.

6) bending characteristics

A BOC package (48 mm x 2 mm x 1.1 mm) was produced by using a sealing resin composition, followed by transfer molding at 175 ° C and 70 seconds, and post-curing at 175 ° C and 2 hours, and a non-contact laser measuring instrument. Measured by

7) Crack resistance evaluation (reliability test)

After 1,000 cycles in a thermal shock tester (Temperature Cycle Test) after precondition, the non-destructive tester SAT (Scanning Acoustic Tomograph) to evaluate the occurrence of cracks and to evaluate the electrical characteristics after leaving the PCT 240 hours.

a) Precondition

BOC-type semiconductor device made of epoxy resin composition was dried for 24 hours at 125 ° C. and subjected to 5 cycles of thermal shock test, and then left for 30 hours at 30 ° C. and 70% relative humidity condition for 96 hours, then IR ripple for 255 ° C. for 10 seconds. The presence of package cracking under the preconditioning condition of passing the furnace once through two repetitions was evaluated. If cracks occurred at this stage, the next stage, the 1,000 cycle thermal shock test, was not conducted.

b) thermal shock test

After 1,000 cycles of the semiconductor package that passed the precondition conditions were left at -65 ° C. for 10 minutes, 25 ° C. for 5 minutes, and 150 ° C. for 10 minutes, the inside and the inside of the semiconductor package were analyzed using SAT, which is a non-destructive tester. External cracks were evaluated.

c) Pressure Cooker Test

After the semiconductor package that passed the precondition condition was left at 121 ° C. and 100% relative humidity for 240 hours, electrical characteristics were evaluated.

[Comparative Examples 1 and 2]

As shown in Table 1 below, each component was weighed in a given composition to prepare an epoxy resin composition in the same manner as in Example 1, and the results of evaluation of physical properties and reliability are shown in Table 2.

Component Content (Unit: Weight%) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Epoxy resin Multiaromatic Modified Epoxy Resin ¹⁾ 2.9 3.7 4.9 3.7 - Biphenyl 4.1 1.5 2.1 2.9 6.9 Hardener Multi-aromatic ²⁾ 1.1 1.5 0.7 - 3.2 Multifunctional ³⁾ 2.0 1.4 2.4 3.5 - Silica content 53㎛ or more ratio 88 0.03 90 0.05 88 0.10 88 8.30 88 0.10 Sphericity 0.85 0.88 0.88 0.85 0.71 Curing accelerator 0.2 0.2 0.2 0.2 0.2 Flame retardant 0.8 0.8 0.8 0.8 0.8 γ-glycithoxypropyltrimethoxysilane 0.4 0.4 0.4 0.4 0.4 Carbon black 0.2 0.2 0.2 0.2 0.2 Carnauba Wax 0.3 0.3 0.3 0.3 0.3 Sum 100.00 100.00 100.00 100.00 100.00

¹⁾ Compound (manufacturer: NIPPON KAYAKU, trade name: CER-3000-L)

²⁾ a compound of formula 3

³⁾ Compound of Formula 4

Evaluation Item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Spiral Flow (inch) 46 40 43 44 42 Tg (℃) 148 144 152 150 128 Electrical Conductivity (㎲ / ㎝) 11 10 11 12 13 Flexural Strength (kgf / ㎡ at 35 ℃) 15 16 15 16 15 Flexural modulus (kgf / ㎡at 35 ℃) 2240 2200 2250 2400 2350 Flame retardant UL 94 V-0 V-0 V-0 V-0 V-1 V-1 Formability Void occurrence number (Visual Inspection) 0 0 0 167 8 Total number of semiconductor devices tested 2,880 2,880 2,880 2,880 2,880 Flexural characteristics Warpage Degree 152 104 170 135 307 responsibility Crack resistance evaluation (thermal shock test) 0 0 0 0 0 Bad after 240 hours PCT 0 0 0 2 5 Total number of semiconductor devices tested 360 360 360 360 360

As shown in Table 2, the resin composition according to the present invention was excellent in bending characteristics and reliability in comparison with the conventional comparative example, it was confirmed that the excellent properties in terms of formability.

Therefore, according to this invention, there exists an effect which can obtain the epoxy resin composition for semiconductor sealing materials which is excellent in moldability, with favorable bending property and reflow-resistant property of a package. Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (6)

In the epoxy resin composition containing an epoxy resin, a hardening | curing agent, and an inorganic filler, WHEREIN: The phenolic compound of the quinobolac structure which contains a biphenyl group in the molecule | numerator represented by following formula (1) as an epoxy resin, and 4,4'- represented by following formula (2). 0.5 to 15% by weight of a modified epoxy resin produced by glycidyl etherification of a mixture of dihydroxy biphenyls; 2 to 10.5 wt% of a mixture of the polyaromatic curing agent represented by the following formula (3) and the polyfunctional curing agent represented by the formula (4) as a curing agent; Epoxy resin composition for semiconductor element sealing, characterized in that it comprises 80 to 93% by weight of fused silica, synthetic silica or a mixture thereof as an inorganic filler. [Formula 1]

(average of n is 1 to 6) [Formula 2]

[Formula 3]

(average of n is 1 to 6) [Formula 4]

 (average of n is 1 to 6) The epoxy resin for sealing a semiconductor device according to claim 1, wherein the multi-aromatic curing agent having the structure of Formula 3 and the multifunctional curing agent having the structure of Formula 4 are mixed in a weight ratio of 20:80 to 60:40. Composition. According to claim 1, wherein the inorganic filler has an average particle of 8.7 to 14.9㎛, the cumulative weight ratio of the particle distribution of 3㎛ or less 15.4 to 23.4% by weight, the cumulative weight ratio of 24㎛ or less 66.9 to 84.3% by weight, 53 Epoxy resin composition for semiconductor element sealing, wherein the weight ratio of particles having a size of µm or more is 0.3% by weight or less, and the average sphericity is 0.85 or more. The tertiary amine, such as benzyldimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol, and tri (dimethylaminomethyl) phenol, 2-methylimidazole, 2-phenylimidazole, etc. Organic phosphines such as polyazoles, triphenylphosphine, diphenylphosphine, phenylphosphine, tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate or mixtures of two or more thereof Epoxy resin composition for sealing a semiconductor device, characterized in that further comprises 0.1 to 0.3% by weight of a curing accelerator selected from the group consisting of. The epoxy resin composition for sealing a semiconductor device according to claim 1, further comprising a modified silicone oil having excellent heat resistance in an amount of 0.5 to 1.5% by weight based on the total epoxy resin composition. 6. The semiconductor device sealing as claimed in claim 5, wherein the modified silicone oil is selected from the group consisting of a silicone oil having an epoxy functional group, a silicone oil having an amine functional group, a silicone oil having a carboxyl functional group or a mixture of two or more thereof. Epoxy resin composition.