JPH11269346A - Epoxy resin composition for sealing semiconductor and semiconductor device using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition with excellent moldability, reliability and flame retardancy, and to obtain a semiconductor device using the above composition. SOLUTION: This epoxy resin composition essentially comprises (A) an epoxy resin, (B) a hardener, (C) an accelerator, (D) pref. 0.01-1.0 wt.% of red phosphorus, (E) magnesium hydroxide, and (F) pref. 70-95 wt.% of an inorganic filler. Using the above composition, semiconductor devices are sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to flame retardancy, moldability,
The present invention relates to a sealing material excellent in reliability and a resin-sealed semiconductor device using the same.

[0002]

2. Description of the Related Art Resin encapsulation is mainly used for encapsulating semiconductor devices in terms of productivity and cost. As this sealing resin, an epoxy resin composition excellent in electrical characteristics, cost, workability and the like is mainly used. However, since the epoxy resin itself has insufficient flame retardancy, a brominated epoxy resin is added to improve the flame retardancy. An antimony compound (antimony trioxide, antimony pentoxide, etc.) having a synergistic effect is used in combination with the brominated flame retardant. In recent years, from the viewpoint of environmental protection, the use of brominated flame retardants suspected of producing dioxin during combustion and antimony, which has been pointed out as a potential carcinogen, has been increasingly required. To meet this demand, various alternative flame retardants have been studied. For example, metal hydrates such as aluminum hydroxide and magnesium hydroxide must be added in large amounts in order to exhibit sufficient flame retardancy, resulting in deterioration of the curability, strength, etc. of the resin composition. I will. Various products have also been proposed for a phosphoric ester-based flame retardant (including a combined use with nitrogen), but none of them can meet the demands for semiconductor encapsulation in terms of moldability and reliability.

[0003] Various proposals have already been made for applying a red phosphorus-based flame retardant to an epoxy resin for semiconductor encapsulation. For example, an epoxy resin composition for semiconductor encapsulation using a red phosphorus-based flame retardant characterized in that the surface layer is made of SixOy (JP-A-7-157542), bismuth oxide,
An epoxy resin composition for semiconductor encapsulation using a red phosphorus-based flame retardant coated with a mixture of bismuth hydroxide and bismuth nitrate (JP-A-8-100108), a red phosphorus-based flame retardant, and an ion scavenger were used. Epoxy resin composition for semiconductor encapsulation (JP-A-8-151427), epoxy resin composition for semiconductor encapsulation using red phosphorus-based flame retardant and boron-based flame retardant (JP-A-8-151505), surface Resin composition for semiconductor encapsulation using red phosphorus coated with phenol resin and aluminum hydroxide (Japanese Patent Application Laid-Open No. 9-165495)
Japanese Patent Application Laid-Open No. 9-90), an epoxy resin composition for semiconductor encapsulation using red phosphorus whose surface is coated with a phenol resin and aluminum hydroxide and defining an epoxy / hardener equivalent ratio, a glass transition temperature, and a coefficient of thermal expansion. No. 227765) has been proposed, but has not always satisfied the strict requirements of semiconductor applications. Simply covering the surface layer with a mixture of SixOy, bismuth oxide, bismuth hydroxide, and bismuth nitrate is inevitable in reducing the moisture resistance due to phosphate ions eluted from red phosphorus, and a sufficient effect can be obtained even by using an ion scavenger. It is difficult. The combined use of red phosphorus and a boron-based flame retardant has a synergistic effect on flame retardancy, and is relatively good in reliability, but curability is reduced.
Since boron is contained in the boron-based flame retardant, there is a problem that it may cause environmental problems. Also, red phosphorus alone whose surface is coated with aluminum hydroxide and a phenolic resin is unsuitable for use in semiconductors due to reduced moisture resistance and high-temperature storage properties, as described above.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an epoxy resin composition for semiconductor encapsulation which does not contain a bromine-based flame retardant or antimony, is excellent in moldability, reliability and flame retardancy, and a semiconductor device using the same. The purpose is to provide.

[0005]

That is, the present invention relates to a sealing material containing epoxy resin, phenol curing agent and inorganic filler as main components, wherein red phosphorus and magnesium hydroxide are blended as essential components as a flame retardant. And a semiconductor device using the same.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As the epoxy resin used in the present invention, those generally used in epoxy resin molding materials for encapsulating electronic parts can be used, and examples thereof include phenol novolak type epoxy resins and ortho resins. Epoxidized novolak resins obtained by the reaction of phenols and aldehydes such as cresol novolak type epoxy resins, diglycidyl ethers such as bisphenol A, bisphenol F, bisphenol S, alkyl-substituted biphenols, diaminodiphenylmethane, isocyanuric acid Glycidylamine-type epoxy resins obtained by the reaction of a polyamine with epichlorohydrin, linear aliphatic epoxy resins obtained by oxidizing olefin bonds with a peracid such as peracetic acid, and alicyclic epoxy resins. It can be used in combination even these at an appropriate number of types. Above all, when an alkyl-substituted biphenol type diepoxy resin such as 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylbiphenyl is used, adhesiveness and moisture absorption are obtained. At the same time, the epoxy resin has a particularly low viscosity at the time of melting, so that the compounding amount of the filler can be greatly improved. As a result, a molding material having excellent reflow crack resistance and moisture resistance can be obtained, and it is preferable to use these epoxy resins in an amount of 60% by weight or more based on the total amount of the epoxy resins used. The reason for this is that if the content is less than 60% by weight, the epoxy resin does not exhibit the characteristics of low moisture absorption and high adhesiveness, and has little effect on solder resistance. The epoxy resin is 4,
Examples include those obtained by epoxidizing 4'-bishydroxy 3,3 ', 5,5'-tetramethylbiphenyl using epichlorohydrin.

As the curing agent of the component (B) used in the present invention, acid anhydrides, amines, phenol compounds and the like can be used, and among them, phenol compounds are preferable. Examples of these phenolic compounds include phenols such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene and formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde and the like. Resin obtained by condensation or co-condensation with aldehydes of the above, a polyparavinylphenol resin, a phenol having a xylylene group synthesized from phenols and dimethoxyparaxylene.
There are aralkyl resins and the like, which may be used alone or in combination of two or more. Among them, a phenol-aralkyl resin having a xylylene group or a structural formula (1)

Embedded image In the case of using a phenolic resin represented by
Since the phenolic resin has a low viscosity at the time of melting at the same time as having good hygroscopicity, the blending amount of the filler can be increased. As a result, a molding material excellent in reflow crack resistance and moisture resistance is obtained, and it is preferable to use 60% by weight or more based on the total amount of the curing agent used. The reason for this is that if the content is less than 60% by weight, the characteristics of the phenolic resin having low hygroscopicity and high adhesiveness are not exhibited, and the effect on the solder resistance is small. Furthermore, 4,
4'-bis (2,3-epoxypropoxy) -3,
When used in combination with an alkyl-substituted biphenol type diepoxy resin such as 3 ′, 5,5′-tetramethylbiphenyl, particularly excellent solder resistance can be obtained. In addition, the epoxy resin (A) and the epoxy resin (B) The equivalent ratio of the curing agent is not particularly limited, but is preferably set in the range of 0.7 to 1.3 in order to reduce the amount of each unreacted component.

In order to accelerate the reaction between the epoxy resin (C) used in the present invention and the curing agent, general curing accelerators can be used widely. Particularly, when a phenol compound is used as the curing agent, Examples of the curing accelerator include 1,8-diazabicyclo (5,4,
0) diazabicycloalkenes such as undecene-7 and derivatives thereof, tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol, 2-methylimidazole, Imidazoles such as -phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; organic phosphines such as tributylphosphine, methyldiphenylphosphine and triphenylphosphine;
Tetra-substituted phosphonium / tetra-substituted borate such as triphenylphosphonium-triphenylborane, triphenylphosphine-benzoquinone adduct, triparatolylphosphine-benzoquinone adduct, tetraphenylphosphonium / tetraphenylborate, 2-ethyl-4
And tetraphenylboron salts such as N-methylimidazole / tetraphenylborate and N-methylmorpholine / tetraphenylborate, which can be used alone or in combination. Among them, triphenylphosphine-benzoquinone is preferable in terms of balance of properties. The adduct, triparatolylphosphine-benzoquinone adduct is preferred.

A method for synthesizing the above-mentioned benzoquinone adduct will be described below using triparatolylphosphine as an example. 1. 44.2 g of triparatolylphosphine was added to acetone 1
Dissolve in 20 g. 2. 17.6 g of p-benzoquinone are dissolved in 80 g of acetone. 3. Mix the solutions of 1 and 2 at room temperature to 80 ° C. 4. The precipitated crystals are filtered, taken out and dried to obtain an adduct of triparatolylphosphine and benzoquinone. In addition, it is necessary to use an inorganic filler as a filler from the viewpoint of reducing hygroscopicity and improving strength. Examples of the inorganic filler include fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, and silicon carbide. , Boron nitride, beryllia, zirconia, and the like, or spherical beads thereof, potassium titanate, silicon carbide,
One or more kinds of single crystal fibers such as silicon nitride and alumina, glass fibers and the like can be blended. Further, examples of the inorganic filler having a flame-retardant effect include aluminum hydroxide and zinc borate, and these can be used alone or in combination. As the compounding amount of the inorganic filler, hygroscopicity,
From the viewpoint of reducing the coefficient of linear expansion and improving the strength, the content is preferably 70% by weight or more. Among the above-mentioned inorganic fillers, fused silica is preferred from the viewpoint of reducing the coefficient of linear expansion, and alumina is preferred from the viewpoint of high thermal conductivity, and the filler shape is spherical from the viewpoint of fluidity during molding and mold abrasion. Is preferred. Other additives include higher fatty acids, higher fatty acid metal salts, release agents such as ester wax, polyolefin wax, coloring agents such as carbon black, epoxy silane, amino silane, ureido silane, vinyl silane, alkyl silane,
Coupling agents such as organic titanates and aluminum alcoholates can be used. Among the above coupling agents, from the viewpoint of flame retardancy and curability, aminosilane is preferable, among which γ-anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane,
γ-anilinopropylmethyldimethoxysilane, γ-anilinopropylmethyldiethoxysilane, and the like are particularly preferable from the viewpoint of adhesion to a lead frame, moisture resistance, and moldability.

As the flame retardant, red phosphorus and magnesium hydroxide are used. In particular, the surface of red phosphorus is magnesium hydroxide,
Alternatively, those coated with magnesium hydroxide and an organic polymer to enhance the stability are preferably used. There are no particular restrictions on the type of resin and the thickness of the coating, but the resin is preferably phenol resin, epoxy resin, PMMA, or the like, which has a high affinity for the base resin, epoxy resin. The thickness of the coating is preferably 1% or more of the average particle diameter of red phosphorus. When the thickness is less than 1%, a problem tends to occur in stability.
The maximum particle diameter of red phosphorus is preferably 200 μm or less. More preferably, the maximum particle size is 150 μm or less and the average particle size is 1
When the thickness is in the range of 0 to 40 μm, variations in moldability, flame retardancy, and the like can be reduced. As a method of surface treatment with a resin and / or a metal hydroxide, known methods (for example, JP-A-61-291644, 61-21)
No. 9706). These can be easily obtained, for example, as Novaled 120 manufactured by Rin Kagaku Kogyo Co., Ltd. The content of red phosphorus in the resin composition is preferably from 0.01 to 1.0%. If it is less than 0.01%, the flame retardancy is insufficient, and if it is more than 1.0%, a problem is likely to occur in the moisture resistance reliability. A range of 0.05 to 0.5% is particularly preferred. The content of magnesium hydroxide is 0.1 ~
20% is preferred. If it is less than 0.1%, the effect of the combined use is not recognized, and if it is more than 20%, a problem tends to occur in fluidity. A range of 0.5 to 10% is particularly preferred.
Magnesium hydroxide which has been subjected to a surface treatment is preferably used. In particular, those surface-treated with stearic acid, a silane coupling agent or the like are preferable. These can be easily obtained, for example, as Kisuma 5A and 5J manufactured by Kyowa Chemical Industry Co., Ltd. As other additives, colorants (such as carbon black), modifiers (such as silicone and silicone rubber), and ion trappers (such as hydrotalcite and antimony-bismuth) can be used.
As a method of producing a molding material using the above-described raw materials, a raw material mixture having a predetermined composition is sufficiently mixed by a mixer or the like, and then kneaded by a hot roll, an extruder, or the like, and then cooled and pulverized to form a molding material. Can be obtained.

[0011] As a method for encapsulating an electronic component using the epoxy resin composition obtained by the present invention, a low pressure transfer molding method is the most common, but it is also possible to employ a method such as injection molding, compression molding, casting or the like. It is possible.
Epoxy resin composition produced using the above means,
Since it does not contain a brominated flame retardant or an antimony compound, it is environmentally friendly and has excellent moldability and reliability, and can be suitably used for sealing of transistors, ICs, LSIs and the like.

[0012]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. Examples 1 and 2, Comparative Examples 1 to 5 First, using various materials shown in Table 1, in Examples 1, 2 and Comparative Examples 1 to 5, after premixing (dry blending) each material, a biaxial roll ( The mixture was kneaded at a roll surface temperature of about 80 ° C. for 10 minutes, and then cooled and pulverized to manufacture.

[0013]

[Table 1]

[0014]

[Table 2]

The materials described in Tables 1 and 2 are as follows. Biphenyl type epoxy resin: YX-400 made by Yuka Shell
0H Phenol / aralkyl resin: XL-225 manufactured by Mitsui Chemicals Co., Ltd. Curing agent having biphenyl skeleton: MEH-7 manufactured by Meiwa Kasei
851 Epoxysilane: KBM-403 manufactured by Shin-Etsu Silicone Polyethylene Wax: PED-191 manufactured by Hoechst Company Brominated epoxy resin: ESB-400 manufactured by Sumitomo Chemical Co., Ltd. Magnesium hydroxide: Kisuma 5J manufactured by Kyowa Chemical Co., Ltd. Fused Silica: Spherical Micron S-CO Each test was performed using a stopper and a transfer molding machine under the conditions of a mold temperature of 180 ° C., a molding pressure of 70 kgf / cm ² , and a curing time of 90 seconds. Spiral flow is
It was measured by EMM11-66. Hot hardness was measured by a Shore hardness tester. Further, using this sealing material, a semiconductor element was molded by a transfer molding machine under the same conditions, and after post-curing (175 ° C./5 h), moisture resistance and solder heat resistance were evaluated. The semiconductor device used for moisture resistance is SOP-28 pin, which absorbs moisture at 85 ° C./85 RH% for 72 hours + 215 ° C. /
After pre-processing for 90 seconds (VPS), the substrate was left in PCT (121 ° C./2 atm) to evaluate the presence / absence of disconnection of wiring on the chip.
The semiconductor device used for the high-temperature storage property was an SOP-28 pin, and the bonding strength of the gold wire after leaving at 175 ° C. for a predetermined time was measured and determined. The semiconductor device used for solder heat resistance is Q
FP80 pin resin-encapsulated semiconductor device (external dimensions 20x
14 × 2.0 mm), and the lead frame is made of 42 alloy material (no processing) and has a chip size of 8 × 10 mm. The resin-encapsulated semiconductor device obtained in this manner was subjected to a soldering heat resistance of 125 ° C./24 h after baking, and then to moisture absorption at 85 ° C./85% RH for a predetermined time, followed by 2 hours.
Judgment was made based on the crack occurrence rate of the resin-encapsulated semiconductor device after the treatment at 40 ° C./10 sec. Table 3 summarizes the above test results.

[0016]

[Table 3]

[0017]

EFFECTS OF THE INVENTION In an epoxy resin composition for encapsulating a semiconductor element containing an epoxy resin, a curing agent and an inorganic filler as main components, reliability is improved by blending red phosphorus and magnesium hydroxide as essential components as flame retardants. It is possible to obtain a molding material which is excellent and has a very small influence on the environment. By sealing a semiconductor element using this molding material, a semiconductor device having excellent reliability and flame retardancy can be obtained.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08K 3/22 C08K 3/22 9/06 9/06 H01L 23/29 H01L 23/30 R 23/31

Claims (9)

[Claims] 1. An epoxy resin for semiconductor encapsulation comprising (A) an epoxy resin (B) a curing agent (C) a curing accelerator (D) red phosphorus (E) magnesium hydroxide and (F) an inorganic filler as essential components. Composition. 2. The composition according to claim 1, wherein the content of red phosphorus is from 0.01 to 0.01 of the total composition.
1.0% by weight and the content of inorganic filler is 70 to 95
2. The epoxy resin composition for semiconductor encapsulation according to claim 1, which is contained by weight. 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the surface of red phosphorus is coated with magnesium hydroxide or magnesium hydroxide and an organic polymer. 4. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the surface of the magnesium hydroxide is coated with a coupling agent, stearic acid, or polyamide. 5. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the epoxy resin is a biphenyl type epoxy compound. 6. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the curing agent is a phenol aralkyl resin having a xylylene group. 7. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the curing agent is a phenol resin represented by the structural formula (1). Embedded image 8. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the curing accelerator is an adduct of triparatolylphosphine and benzoquinone. 9. An epoxy resin-encapsulated semiconductor device in which a semiconductor element is encapsulated by using the epoxy resin composition for encapsulating a semiconductor according to claim 1.