KR100504604B1 - Epoxy molding compound for sealing of semiconductor device - Google Patents

Abstract

In the present invention, biphenyl epoxy is an essential component, and triphenylphosphine or imide, which is generally used as a curing catalyst in an epoxy resin composition using an allocresol noblock epoxy resin, a phenolic or xylolic curing agent, is used. Epoxy resin for molding semiconductor devices having excellent storage stability and reliability by using 2- (dimethylaminomethyl) phenol or 2,4,6-tris (dimethylaminomethyl) phenol of the following formula (3) as a curing catalyst instead of a sol-based catalyst. To a composition.

Formula 3

           (a) (b)

Description

Epoxy resin composition for semiconductor element sealing {EPOXY MOLDING COMPOUND FOR SEALING OF SEMICONDUCTOR DEVICE}

The present invention relates to an epoxy resin composition for sealing semiconductor devices that improves reliability and molding properties by improving adhesion problems between wafer chips and epoxy encapsulants due to thermal shock changes, and more particularly, based on a biphenyl structure. It has an epoxy structure and has excellent mechanical hygroscopic properties including allocresol novolac epoxy resin, phenol novolac or xylox curing agent, aminophenol curing catalyst, wax, and inorganic filler. An epoxy resin composition for semiconductor element sealing.

In recent years, the degree of integration of semiconductor devices is improving day by day, and thus, the size of wirings, the size of devices, the size of cells, and the number of multilayer wirings are rapidly progressing. On the other hand, a package that protects a semiconductor element from the external environment is accelerating its size and thickness from the viewpoint of high-density mounting on a printed board, that is, surface mounting.

As described above, in a resin-sealed semiconductor device in which a large semiconductor device is sealed in a small and thin package, failure frequency is increased due to package crack or aluminum pad corrosion due to thermal stress caused by temperature and humidity changes in the external environment.

Accordingly, there is a demand for a highly reliable semiconductor element epoxy encapsulant through crack resistance and low stress of the epoxy resin encapsulation material for sealing.

In order to satisfy this, there are methods of improving moisture absorption, improving adhesive strength and high temperature strength in order to improve crack resistance, and controlling the filler for low stress, lowering the coefficient of thermal expansion, and low elasticity by adding a modifier. How to achieve this is known.

High filling technology due to low stress (High Loading according to filler combination) has already been developed a lot, it was possible to suppress the package thermal stress accordingly.

In addition, Japanese Patent Laid-Open Nos. 63-1894 and 5-291436 propose a method of low elasticity, which examines modification by various rubber components and blends and modifies a silicone polymer having excellent thermal stability. Epoxy resin molding materials are widely adopted.

In particular, in this method, since silicone oil is incompatible with the epoxy resin and the curing agent, which are the base resin of the molding material, the silicone oil is in the form of fine particle dispersion (island structure) in the base resin, thereby achieving low elasticity while maintaining heat resistance.

However, the technique using biphenyl epoxy resin to achieve high reliability is caused by a large number of molding defects due to changes in flow characteristics, etc. when applied to the molding process of the semiconductor package due to the deterioration of storage properties when applying the biphenyl epoxy resin There has been a limitation in use and there is a demand for improvement.

SUMMARY OF THE INVENTION An object of the present invention is to meet the above demands. In the epoxy resin composition using an allocresol novolac epoxy resin, a phenol-based or xyloco-based curing agent as a biphenyl epoxy resin, it is generally used as a curing catalyst. Epoxy resin for sealing semiconductor devices with excellent storage stability and reliability using 2- (dimethylaminomethyl) phenol or 2,4,6-tris (dimethylaminomethyl) phenol, not triphenylphosphine or imidazole catalyst It is to provide a composition.

That is, the present invention is an epoxy resin composition comprising an epoxy resin, a curing agent, a curing catalyst, an inorganic filler, and other additives, wherein the epoxy resin is a biphenyl-based epoxy and an oxocresol novolac-type epoxy represented by Formula 1 below. Resin, wherein the curing agent is a silicone-modified epoxy product represented by Chemical Formula 2, and 2- (dimethylaminomethyl) phenol or 2,4,6-tris (dimethylaminomethyl) represented by Chemical Formula 3 as the curing catalyst. The total amount of the said inorganic filler is 82-90 weight% using the phenol, It is related with the epoxy resin composition for semiconductor element sealing characterized by the above-mentioned.

                 (a) (b)

     (a) (b)

            (a) (b)

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

In the present invention, the epoxy resin used is an epoxy resin having the structure of Formula 1, the epoxy equivalent of 160 to 250 high purity, the softening point is suitable in the range of 40 to 80 ℃, to ensure high reliability and high fluidity ( It is based on the use of a biphenyl epoxy resin such as a) and may be selected from diglycidyl ether bisphenol A, diglycidyl ether F, olsocresol novolac dicyclopentadiene, and naphthalene type. Thus, biphenyl epoxy resin 100% or one or two different types of epoxy resin can be mixed and used. At this time, the composition is 10% or more biphenyl-based epoxy resin, the epoxy resin is suitably 3.0 to 12.0% by weight of the total resin composition.

As a curing agent used in the present invention, a silicone-modified epoxy product such as a phenol-based (a) or xyloxi-based (b) curing agent represented by Formula 2 may be used in an amount of 2.0 to 10 wt%.

In addition, the present invention is characterized in that a novel curing catalyst is introduced to solve the storage problem that causes problems in general use despite having excellent reliability in the epoxy resin composition using biphenyl epoxy.

As such a novel curing catalyst, biphenylepoxy resin is obtained by using 2- (dimethylaminomethyl) phenol or 2,4,6-tris (dimethylaminomethyl) phenol as shown in Formulas (a) and (b). It is possible to ensure excellent reliability and storage stability of the epoxy resin composition containing a component is excellent in the storage properties, regardless of mixing of the curing agent, epoxy resin and the like.

As a result, the conventional biphenyl epoxy resin has an advantage of having excellent reliability in terms of resin properties, but it lacks storage stability and is used within 48 hours after standing at room temperature in the molding process during semiconductor encapsulation despite low temperature storage below 5 ° C. It should solve the problem of usage.

Inorganic fillers used in the present invention preferably use molten or synthetic silica having an average particle of 0.1-35.0 µm, and the amount of the filler is preferably 82 to 90% by weight based on the total composition.

When the amount of the inorganic filler used is less than 82% by weight, strength and low thermal expansion cannot be realized, and moisture permeation becomes easy, and reliability characteristics are lowered. In addition, when the filling amount of the inorganic filler exceeds 90% by weight, there is a fear that the moldability due to the deterioration of the flow characteristics deteriorate.

In the present invention, other additives may be included in addition to the above components, and as the wax used in the molding point of view, higher fatty acids, natural fatty acid ester waxes, and the like may be used. In addition, coloring agents such as carbon black and organic and inorganic dyes may be used. , Crosslinking enhancers, flame retardant aids and the like can be used as necessary.

In the present invention, a method for producing an epoxy resin composition is obtained by uniformly pulverizing and mixing a predetermined compounding amount using a Henschel mixer or Lloyd's mixer, and then obtaining a primary powder product, using a roll mill or a kneader. Melt kneading in minutes, cooling and grinding can be used.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Examples 1-4 and Comparative 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 powder primary composition. After melt kneading at 100 ° C. for 7 minutes, an epoxy resin composition was prepared by cooling and pulverizing. Comparative Examples 1-4 were manufactured by the same method according to the composition shown in Table 2.

The epoxy resin composition thus obtained was evaluated for physical properties and reliability by the following method, and when molding a small outling package (SOP) -type semiconductor device for reliability test, using an MPS (Multi Plunger System) molding machine at 50 ° C. at 175 ° C. After molding for a second, and post-curing at 175 ℃ for 6 hours, the thermal shock test over time to evaluate this.

For storage evaluation, the flow characteristics of spiral flow were measured at 25 ° C. and 50% relative humidity.

Examples and comparative examples for the epoxy resin composition are shown in Table 1 and Table 2, respectively, and the general physical properties evaluated therefrom are shown in Table 3, and the storage properties are shown in Table 4, respectively.

                                       (Unit: weight%) Ingredient Example 1 Example 2 Example 3 Example 4 Epoxy resin ¹⁾ Allsocresol novolac resin - - 1.70 4.20 ⁴⁾ Biphenyl Epoxy Resin 8.55 8.55 6.85 4.35 ⁵⁾ Bromide Epoxy Resin 1.00 1.00 1.00 1.00 Antimony trioxide 0.33 0.33 0.33 0.33 ⁶⁾ Phenolic novolac resin 4.20 4.20 4.20 4.20 Triphenylphosphine - - 0.05 0.05 2-ethyl-4-methylimidazole - - - - 2- (dimethylaminomethyl) phenol 0.15 - 0.10 - 2,4,6tris (dimethylaminomethyl) phenol - 0.15 - 0.10 Inorganic filler 85.00 85.00 85.00 85.00 ⁷⁾ γ-glycithoxypropyltrimethoxysilane 0.42 0.42 0.42 0.42 Carbon black 0.20 0.20 0.20 0.20 Carnauba Wax 0.15 0.15 0.15 0.15 system 100.00 100.00 100.00 100.00

¹⁾ Nippon kayaku ^, Japan: EOCN 1020-55

⁴⁾ Yucca Shell: YX-4000 H

⁵⁾ Kayaku, Japan: 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 - - 1.70 4.20 ⁴⁾ Biphenyl Epoxy Resin 8.55 8.55 6.85 4.35 ⁵⁾ Bromide Epoxy Resin 1.00 1.00 1.00 1.00 Antimony trioxide 0.33 0.33 0.33 0.33 ⁶⁾ Phenolic novolac resin 4.20 4.20 4.20 4.20 Triphenylphosphine 0.15 - 0.05 0.10 2-ethyl-4-methylimidazole - 0.15 0.10 0.05 2- (dimethylaminomethyl) phenol - - - - 2,4,6tris (dimethylaminomethyl) phenol - - - - Inorganic filler 85.00 85.00 85.00 85.00 ⁷⁾ -Glycithoxypropyltrimethoxysilane 0.42 0.42 0.42 0.42 Carbon black 0.20 0.20 0.20 0.20 Carnauba Wax 0.15 0.15 0.15 0.15 system 100.00 100.00 100.00 100.00

Evaluation item Example Comparative example One 2 3 4 One 2 3 4 Spiral Flow (inch) 33 31 34 35 32 31 36 30 Glass transition temperature Tg (℃) 128 125 137 144 123 122 132 149 Thermal expansion coefficient α (㎛ / m. ℃) 11.4 11.2 11.8 11.8 11.2 11.9 11.5 11.2 Hot hardness 64 68 68 72 59 62 64 59 Adhesive force (kgf) 77 74 62 58 70 72 63 52 Flexural Strength (kgf / ㎡) 15.8 15.2 114.8 14.9 15.5 14.1 15.3 14.6 Flexural modulus (kgf / mm2) 2150 2250 2100 2300 2250 2100 2050 2250

Property evaluation method

럴 Spiral Flow

 Molds were manufactured on the basis of EMI standard, and the flow length was evaluated at molding temperature (175 ℃) and molding pressure of 70kgf / mm2.

Hard Hot Hardeness: Hardness was measured by Showa D hardness tester at 175 ℃ for 90 seconds.

㉢ glass transition temperature (Tg), thermal expansion coefficient

   It was evaluated by TMA (Thermomechanical Analyser) (heating rate 10 ℃ / min).

㉣ Adhesion: The tensile strength of the lead frame (alloy 44) and the epoxy encapsulant (UTM) was evaluated.

㉤ flexural strength and flexural modulus

   It was evaluated according to ASTM D190 using a universal test machine (UTM).

Evaluation item Example Comparative example One 2 3 4 One 2 3 4 Spiral Flow (inch) 0 days 33 31 34 35 32 31 36 30 1/2 day 33 30 32 34 31 29 35 29 1 day 32 30 34 34 30 27 32 27 2 days 32 29 31 33 29 24 29 25 3 days 31 28 29 32 27 22 28 25 4 days 30 29 29 32 26 18 26 24 5 days 30 28 29 30 25 17 23 23 6 days 29 27 28 31 24 14 23 22 7 days 27 27 28 29 22 12 21 22

* Spiral Flow

Mold was manufactured based on EMMI standard to evaluate the flow length at molding temperature (175 ℃) and molding pressure 70kgf / ㎠, measurement condition (25 ℃, 50% relative humidity)

In the case of the general physical properties shown in Table 2 did not show a large change depending on the reaction catalyst, but when looking at the results measured by using a spiral follower in Table 3 it can be seen that a significant difference according to the type of catalyst.

As described above, a biphenyl epoxy resin alone or mixed with other epoxy resins, and a phenyl novolak resin or xylox resin as a curing agent is an epoxy resin composition for sealing semiconductor devices, wherein 2- (dimethylaminomethyl By using) phenol or 2,4,6-tris (dimethylaminomethyl) phenol as a curing catalyst, a resin composition having excellent storage effect can be obtained, and stable moldability and workability in the mold process can be secured.

Claims (2)

 In the epoxy resin composition comprising a biphenyl-based and allocresol novolac-based epoxy resin, a curing agent, a curing catalyst, an inorganic filler, the curing catalyst is 2- (dimethylaminomethyl) phenol (a) or 2, 4,6-tris (dimethylaminomethyl) phenol (b) containing 0.03 to 0.2% by weight based on the total composition, epoxy resin composition for sealing semiconductor elements. Formula 3            (a) (b) Biphenyl-based and allocresol novolac-based epoxy resins 3.0 to 12.0% by weight Phenolic novolac resin 2.0 to 10% by weight 2- (dimethylaminomethyl) phenol or 0.03 to 0.2% by weight of 2,4,6-tris (dimethylaminomethyl) phenol, 0.33% by weight of antimony trioxide Inorganic fillers 82 to 90% by weight 0.5 wt% additive Epoxy resin composition for sealing semiconductor elements, characterized in that the composition.