KR101464700B1 - Epoxy resin composition for semiconductor - Google Patents

Abstract

　　식 (1) (Purpose) Manufacture of Epoxy Resin Composition for Semiconductor with Excellent Flowability, Storage Stability, and Molding Properties
(Composition) An epoxy resin composition comprising an epoxy resin, a curing agent, a curing accelerator, a filler, and the like, and is characterized by including the following TetrahydroxyDiNaphthalene (THDN) component as a curing accelerator.

Equation (1)

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition for semiconductor,

 Epoxy resins are used in various fields such as paints, adhesives, and electrical insulation materials because they are excellent in heat resistance, moisture resistance, electrical characteristics, and adhesiveness. As a method of forming electronic circuit components such as semiconductors, conventionally, hermetic molding methods using metals and ceramics and resin molding methods using resins such as phenol resin, silicone resin, and epoxy resin are available. However, from the viewpoint of economy, productivity and physical properties, it is known that resin molding method using epoxy resin is the best.

2. Description of the Related Art [0002] In recent years, a semiconductor package mounting method for a printed circuit board has become increasingly densified and automated, and a surface mounting method in which a package on a surface of a substrate is soldered directly is a mainstream in an insertion mounting method in which a lead pin is inserted into a substrate hole. Accordingly, the package has been changed from a conventional DIP (Dual Inline Pacakge) to a flat FPP (Flat Plastic Package) suitable for high-density mounting and surface mounting. As the microfabrication technology advances, the degree of integration of semiconductors is dramatically improved, the occupied area occupied by the semiconductor chips in the package is increased, and the package becomes larger and multi-pinned. Therefore, if the moldability of the semiconductor package is not increased, the package may be unfilled or voids may be formed, which may lead to a reduction in productivity. In recent semiconductor molding methods, the epoxy resin molding is made into a tablet state and molded using a low-pressure transfer molding machine. Since the epoxy resin molding is in a B-stage state, it is left to stand at room temperature or when the storage period at a low temperature is long, the curing reaction occurs and the formability is deteriorated. Particularly, since aging is generally performed at room temperature before semiconductor molding, the moldability is often weakened in this case. In this case, appearance defects (unfilled voids, pinholes) and internal defects (wire strain, inner voids, etc.) are generated during semiconductor molding, which causes problems in reliability of the semiconductor package such as humidity resistance reliability and soldering heat resistance. The main reason for aging is that when the resin is stored at a low temperature and molded directly at room temperature, the surface history and the internal history of the epoxy resin molded article are different, which causes many defects in molding.

For this reason, various types of curing accelerators have been developed in order to improve the molding characteristics of the resin composition for semiconductor use (JP-A-6-271653, JP-A 6-322073, JP-A 6-326220) Here too, the moldability is not improved without decreasing the production efficiency. Particularly, since a high filling technology is required according to recent demands of semiconductor high density, high heat resistance, and high humidity resistance, a biphenyl type low viscosity epoxy resin is used in the conventional novolak type epoxy resin. In the case of such a biphenyl epoxy resin, the curing reaction becomes incomplete due to the interaction between the biphenyl groups, resulting in a decrease in molding and curing properties. (WG Kim et al., Journal of Applied Polymer Science, Vol. 96, pp. 2287-2299, 2005)

It is an object of the present invention to provide a novel epoxy curing accelerator for improving moldability, curing properties and preservation stability, and to provide epoxy resin compositions for semiconductors excellent in flowability and curing properties.

In order to solve the above problems, the present invention is characterized in that the epoxy resin composition for semiconductor is constituted as follows.

(A) and a curing agent (B), a curing accelerator (c) and a filler (D), the curing accelerator (C) contains a tetrahydroxy dinaphthalene Resin composition

　　　　　　　　　　식 (1)

Equation (1)

As described above, the epoxy resin composition according to the present invention is excellent in fluidity, storage stability and mechanical properties of an epoxy resin composition by adding a compound represented by formula (1) as a curing accelerator to an existing catalyst system. Therefore, by using the epoxy resin composition for semiconductors according to the present invention, it is possible to manufacture a semiconductor element having excellent moldability and reliability at the time of molding a semiconductor element.

(For A. epoxy resin)

The epoxy resin (A) used in the present invention is characterized by having two or more epoxy groups in a molecule. For example, cresol novolak type epoxy resin, phenol novolak type epoxy resin, biphenyl type epoxy resin, bisphenol A type An epoxy resin, a bisphenol F type epoxy resin, a linear aliphatic epoxy resin, an alicyclic epoxy resin, a heterocyclic epoxy resin, an epoxy resin containing a spiro ring, and a halogenated epoxy resin. In the present invention, two or more epoxy resins (A) can be used. For example, a novolak type epoxy resin represented by the following formula (2), a biphenyl type epoxy resin represented by the formula (3), and a phenol-biphenyl type epoxy resin represented by the formula (4).

식(2)

Equation (2)

식(3)

Equation (3)

식(4)

Equation (4)

Particularly, as the preferred epoxy resin (A), 40 wt% or more, particularly 70 wt% or more, of the phenol-biphenyl type epoxy resin represented by the formula (4) is preferably used. The above-mentioned epoxy resin (A) may be used alone or in combination to exhibit sufficient effects, and an additional compound having a partial reaction with the epoxy resin may also be used. The blending amount of the epoxy resin (A) used in the present invention is usually 3 to 15%, preferably 3 to 12% by weight. If the blend amount of the epoxy resin (A) is less than 3 wt%, the formability or adhesiveness is insufficient. If the blend amount exceeds 15 wt%, the linear expansion coefficient increases and the reliability of the semiconductor is adversely affected.

(B. Hardener) The curing agent used in the present invention is a substance capable of reacting with the epoxy resin (A) to form a cured product. Specific examples thereof include phenol novolak resin, cresol novolak resin, various novolacs synthesized from bisphenol A and resole Resin, various polyhydric phenol compounds such as Tris (hydroxyphenyl) methane and dihydroxybiphenyl, maleic anhydride, phthalic anhydride, isonic anhydride and aromatic amines such as methaphenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone. For the molding of semiconductors, phenolic curing agents are widely used in terms of heat resistance, moisture resistance and storage stability, and it is preferable that two or more kinds of curing agents are used in parallel depending on the application. The blending amount of the curing agent (B) used in the present invention is usually 0.1 to 10 wt% with respect to the whole composition. Preferably, 0.5 to 7 wt% is used. The compounding ratio of the epoxy resin (A) to the curing agent (B) is preferably in the range of 0.5 to 1.5, particularly 0.8 to 1.2, in terms of the chemical equivalent ratio of (B) to (A), depending on the requirements of mechanical properties and moisture resistance reliability.

(C. Curing accelerator) The curing accelerator used in the present invention is a substance that promotes the reaction between the epoxy resin and the curing agent. In general, tertiary amines, organometallic compounds, organic phosphorus compounds, imidazoles, boron compounds and the like can be used. Tertiary amines include benzyldimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (diaminomethyl) phenol, 2,4,6-tris (diaminomethyl) phenol and tri-2-ethylhexyl acid. Organometallic compounds include chromium acetylacetonate, zinc acetylacetonate, and nickel acetylacetonate. Organic phosphorus compounds include tris-4-methoxy phosphine, tetrabutylphosphonium bromide, butyl triphenylphophonium bromide, triphenylphophine, triphenyl phosphine triphenylborane, and triphenyl phosphine 1,4-benzoquinone adducts. The imidazoles include 2-methyl imidazole, 2-amino imidazole, 2-methyl-1-vinyl imidazole, 2-ethyl-4-methyl imidazole and 2-heptadecyl imidazole. The boron compounds include trifluoroborane-n-hexyl amine, trifluoroborane monoethyl amine, tetrafluoroborane-triethylamine, and tetrafluoroborane amine. In addition, there are 1,8-diaza bicycleundecene (DBU), DBU and phenol novolac resin salts.

In order to improve the moldability, storage stability and curing properties of the epoxy resin composition, the curing characteristics and formability of the above-mentioned biphenyl epoxy resin composition are not improved as general curing accelerators, Compound is added and used. In particular, it is preferable to use a curing accelerator obtained by adding a compound of formula (1) to a triphenylphophine derivative exhibiting excellent flowability of the epoxy resin composition as a curing accelerator. Triphenyl phosphine derivatives include triphenyl phosphine and an epoxy curing agent, triphenyl phosphine oxide, butyltriphenylphosphonium bromide, and triphenylphosphinetriphenyl borate. Especially, compound (Eq. (5)) prepared by adding compound of formula (1) to the adduct of triphenylphosphine and epoxy curing agent is more effective.

식(5)

Equation (5)

The method of synthesizing the curing accelerator (THDN-TPP) represented by the above formula (5) is as follows.

(Synthesis of THDN-TPP)

First, add 10 g (1 eq) of 2,7-Dihydroxy-napthalene in a 1 L reaction vessel, add 50 ml of ethanol and stir for 45 ° C. Add 300 ml of HCl (1N) . Add 3.21 g (0.6 eq) of Formaldehyde solution to precipitate spherical white solids. The reaction mixture was stirred at room temperature for 1 hour, cooled at room temperature, filtered, and sufficiently washed with distilled water. After drying, the yield (9.3 g, 92%) was measured and confirmed to be THDN by NMR;

^{1 H NMR (400MHz, DMSO)} : δ 9.669 (s, 2H), 9.144 (s, 2H), 7.480-7.458 (d, 2H), 7.443-7.421 (d, 2H), 7.387-7.383 (d, 2H) , 6.997-6.975 (d, 2H), 6.751-6.725 (dd, 2H), 4.481 (s, 2H)

Now, to synthesize THDN-TPP, add 31.59 g (1 eq) of THDN and 39.85 g (1 eq) of Tetraphenylphosphonium Bromide (TPPB) to the 1 L reaction vessel. Add 200 ml of ethanol and uniformly dissolve. After 3.8 g (1 eq) of NaOH dissolved in 15 ml of distilled water is slowly added, a greenish yellow crystal is formed and agglomerates. After filtration, the filtrate was washed with 100 ml of ethanol and the yield (60.07 g, 94%) was measured. It was confirmed by NMR that THDN-TPP was obtained;

^{1 H NMR (400MHz, DMSO)} : δ 7.966-7.925 (m, 4H), 7.822-7.691 (m, 16H), 7.572 (s, 2H), 7.372-7.351 (d, 2H), 7.245-7.223 (d, 2H), 6.622-6.574 (m, 4H), 4.254 (s, 2H)

(D. Filler) The filler used in the present invention is a material that effectively improves the mechanical properties and low-stressing of the epoxy resin composition. Examples of commonly used materials include fused silica, crystalline silica, calcium carbonate, magnesium carbonate, Alumina, Magnesia, Clay, Talc, calcium silicate, titanium oxide, antimony oxide, asbestos and glass fiber. For low stresses, fused silica with a low coefficient of linear expansion is recommended. The fused silica mentioned above refers to amorphous silica having a true specific gravity of 2.3 or less and includes amorphous silica obtained by melting crystalline silica or synthesized from various raw materials. Although the shape and the particle diameter of the fused silica are not particularly limited, fused silica containing 50 to 99 wt% of spherical fused silica having an average particle diameter of 5 탆 or more and 30 탆 or less and 1 to 50 wt% of spherical fused silica having an average particle diameter of 1 탆 or less It is preferable that the content of the filler is 40 wt% or more, preferably 60 wt% or more. In the present invention, the ratio of the filler is 70 to 95 wt.%, Preferably 80 to 95 wt.%, As a whole, though it depends on physical properties such as moldability, low stress and high temperature strength.

   The following materials may also be added to the epoxy resin composition of the present invention. In order to improve the reliability of the semiconductor resin molding material, the filler is preferably surface-treated with a crosslinking agent such as a silane crosslinking agent or a titanate crosslinking agent. As the crosslinking agent, it is preferable to use a silane crosslinking agent such as epoxy silane, amino silane or mercaptosilane.

   Although not necessarily used in the composition of the present invention, a brominated compound can be added. The purpose of using it is as a flame retardant. Specific examples are as follows. A brominated epoxy resin such as a brominated bisphenol A type epoxy resin and a brominated phenol novolak type epoxy resin, a brominated polymethyl methacrylate resin, a brominated polystyrene resin, tetrabromobisphenol A and decabromodiphenylether. Among them, brominated epoxy resin is excellent in moldability and reliability. Antimony compounds can also be used to improve flame retardancy. Specific examples thereof include antimony trioxide, antimony tetraoxide, and antimony pentoxide.

In addition to the composition of the present invention, other coloring agents such as carbon black, iron oxide, silicon rubber, modified silicone oil, low stressing agents such as modified polybutadiene, and release agents such as polyethylene wax and carnauba wax may be used.

The method of preparing the epoxy resin composition of the present invention is premixing the composition by using a lighten mixer, a super mixer, a Henschel mixer or the like, followed by melt-kneading at 80 to 150 ° C using a roll mill, a continuous kneader, I do. It is cooled using a cooling belt and crushed by a crusher.

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited by these examples.

(Examples 1 to 3)

Table 1. , The mixture was homogeneously mixed using a Henschel mixer and then melted and kneaded at 100 to 120 ° C using a continuous kneader, followed by cooling and pulverizing to prepare an epoxy resin composition for semiconductor molding. Various physical properties were evaluated by the following methods. The results are shown in Table 2.

(Flowability / spiral flow): Measured using a transfer molding press at 175 占 폚 using an evaluation mold according to EMMI-1-66.

(Storage stability): The reduction rate of the spiral flow after storage at 30 ° C and 50% RH for 96 hours was measured based on the value of the spiral flow before preservation. The lower the rate of decrease, the better the storage stability.

(Bending Strength): Standard specimens were prepared in accordance with ASTM D-790, and then cured at 180 ° C for 4 hours using UTM.

(Comparative Examples 1 to 3)

The same procedure as in Examples 1 to 3 was carried out according to the composition shown in Table 1 below, and the properties were evaluated. The results are shown in Table 2.

Ingredient composition table (unit: wt.%) ingredient Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Epoxy resin I ¹ 7.03 - - 7.29 - - Epoxy resin II ² - 8.28 7.25 - 8.65 7.52 Hardener ³ 7.55 6.19 5.42 7.83 6.46 5.62 THDN-TPP 0.96 0.95 0.83 - - - TPP ⁴ - - - 0.40 -. 0.34 1B2MI ⁵ - - - - 0.27 Filler I ⁶ 58.10 58.10 59.50 58.10 58.10 59.50 Filler II ⁷ 16.60 16.60 17.00 16.60 16.60 17.00 Filler III ⁸ 8.30 8.30 8.50 8.30 8.30 8.50 Silane 0.75 0.75 0.77 0.75 0.75 0.77 Carnauba Wax 0.41 0.53 0.43 0.43 0.57 0.45 Carbon Black 0.30 0.30 0.30 0.30 0.30 0.30

1) Epoxy resin I: Biphenyl Epoxy resin (YX-4000H, JER, epoxy equivalent = 190)

2) Epoxy resin II: Phenol-Biphenyl Epoxy resin (NC-3000p, Nippon Kayaku, epoxy equivalent = 273)

3) Hardener: Phenol-Biphenyl resin (MEH-7851SS, Meihwa Chem., Hydroxyl equivalent = 204)

4) TPP: Triphenylphosphine

5) 1B2MI: 1-butyl-2-methyl imidazole

6) Filler I: spherical molten Silica having an average particle diameter of 28 탆

7) Filler II: spherical fused silica having an average particle diameter of 6 탆

8) Filler III: spherical fused silica having an average particle diameter of 1 탆

Evaluation table for each composition Evaluation items Spiral flow (inch) Storage stability (%) Bending strength (kgf / mm ² ) Example 1 49 8.5 15.8 Example 2 50 6.7 15.9 Example 3 47 8.2 16.5 Comparative Example 1 42 22.3 13.2 Comparative Example 2 41 27.5 12.2 Comparative Example 3 38 25.2 12.8

The present invention relates to an epoxy resin composition for semiconductor molding which is excellent in fluidity, storage stability and cured property.

Claims (2)

In the epoxy composition containing the epoxy resin (A), the curing agent (B), the curing accelerator (C) and the filler (D), the compound represented by the following formula (1) is contained in the curing accelerator An epoxy resin composition

Equation (1)  The curing accelerator according to claim 1, wherein the curing accelerator is contained in an amount of 0.1 wt% to 10 wt% with respect to the epoxy resin (A) contained in the composition, and the compound represented by the formula (1) By weight based on 100% by weight of the epoxy resin.