JP2000109647A - Semiconductor sealing epoxy resin composition and semiconductor device using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor sealing resin composition excellent in moldability, reliability and flame retardance which does not contain a bromine type flame retardant and antimony, and a semiconductor device using the same. SOLUTION: Semiconductor elements are sealed with a sealing medium comprising (A) an epoxy resin, (B) a curing agent, (C) a curing accelerator, (D) a metal hydrate, and (E) an inorganic filler as the essential components, the metal hydrate (D) having a center particle diameter of 14-25 μm with not more than 30 wt.% particles having a particle diameter of not greater than 10 μm and not more than 5 wt.% particles having a particle diameter of not greater than 5 μm.

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 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 epoxy resins have insufficient flame retardancy, flame retardants such as brominated epoxy resins and antimony trioxide are usually added to improve flame retardancy. However, these flame retardants are being regarded as a problem because the gas generated during combustion has an adverse effect on the environment, and in recent years, from the viewpoint of environmental protection, the demand for their use has been increasing. To meet this demand, various alternative flame retardants have been studied. For example, various proposals have already been made for applying a red phosphorus-based flame retardant to an epoxy resin for semiconductor encapsulation. For example, if the surface layer is S
ixOy using a red phosphorus-based flame retardant (Japanese Unexamined Patent Publication No.
157542), using a red phosphorus-based flame retardant coated with a mixture of bismuth and bismuth nitrate (JP-A-8-15)
No. 1427), those using red phosphorus-based flame retardants and boron-based flame retardants (JP-A-8-151505), those using red phosphorus whose surface is coated with a phenol resin and aluminum hydroxide (JP-A-9-165495). And a resin composition 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 thermal expansion coefficient (JP-A-9-227765). However, they did not always satisfy the strict requirements of semiconductor applications. Simply coating the surface layer with a mixture of SixOy, bismuth oxide, bismuth hydroxide, and bismuth nitrate is inevitable in reducing moisture resistance due to phosphate ions eluted from red phosphorus, and sufficient effects can be obtained even with ion scavengers. It is difficult. Red phosphorus alone, whose surface is coated with aluminum hydroxide and a phenolic resin, has poor moisture resistance and high-temperature storage properties as described above, and is unsuitable for semiconductor applications. On the other hand, proposals have been made to improve moisture resistance and high-temperature storage properties by using metal hydrates such as aluminum hydroxide and magnesium hydroxide as flame retardants (JP-A-64-73651, JP-A-9-1997). 241483
No.). However, in order to obtain a metal hydrate-based flame retardant, a large amount of addition is required, and the mechanical properties of a molded product are deteriorated. In response to this problem, it was conventionally thought that reducing the particle size of the metal hydrate could improve the flame retardancy and reduce the amount added (synthetic resin 1996. Nov Vol. 42 No. 11 Latest trends in fuel technology). However, the addition of a metal hydrate having a small particle size causes a decrease in fluidity, curability, and the like, and is not suitable for semiconductor encapsulation. The combined effect of metal oxides and metal hydrates has been reported previously (Mitsubishi Electric Wire & Cable Times No. 75, April 1988, International Wire & Cable S
ymposium Proceeding 1986), an epoxy resin composition using an oxide and a hydrate of a specific group of the periodic table in combination (Japanese Unexamined Patent Publication No.
No. 100337) has been proposed, but it is difficult to achieve both flame retardancy and moldability, and none of them can meet the demand for semiconductor encapsulation.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been developed in view of the above circumstances, and contains no bromine-based flame retardant or antimony, and has excellent moldability, reliability and flame retardancy. It is an object to provide a resin composition and a semiconductor device using the same. One of the alternatives to brominated flame retardants is metal hydrate. Aluminum hydroxide, magnesium hydroxide, and the like are widely known as metal hydrate-based flame retardants. In particular, aluminum hydroxide is available on the market in various particle sizes. However, it is necessary to add a large amount of these metal hydrates in order to satisfy flame retardancy by using them alone. In the case of epoxy resins for semiconductor encapsulation, curability and mold release properties are reduced, and application to mass production is required. Was difficult. As a result of intensive studies conducted by the present inventors to solve these problems, the flame retardancy was increased by setting the particle size of the metal hydrate to a specific range, and this was a disadvantage of the conventional product. It has been found that a decrease in fluidity and curability can be prevented. In addition, it has been found that by performing a specific surface treatment on the surface of the metal hydrate, the dispersibility can be further improved, and the flame retardancy and the fluidity can be improved.

[0004]

That is, the present invention relates to a sealing material containing an epoxy resin, a phenol curing agent and an inorganic filler as main components and having a center particle diameter of 14 to 2 as a flame retardant.
It is characterized in that a metal hydrate having a specific particle size of 5 μm and having a particle size of 10 μm or less being 30% by weight or less of the whole composition and having a particle size of 5 μm or less being 5% by weight or less is used. The present invention relates to an epoxy resin composition for semiconductor encapsulation and a semiconductor device using the same.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As the epoxy resin used in the present invention, those generally used in epoxy resin molding materials for encapsulating electronic parts can be used. For example, a phenol novolac type epoxy resin, Epoxidized novolak resins of phenols and aldehydes, including orthocresol novolak type epoxy resins, polyamines such as diglycidyl ethers such as bisphenol A, bisphenol F, bisphenol S, and alkyl-substituted biphenols, diaminodiphenylmethane, and isocyanuric acid Glycidylamine-type epoxy resins obtained by the reaction of epoxide and epichlorohydrin, linear aliphatic epoxy resins obtained by oxidizing olefin bonds with a peracid such as peracetic acid, and alicyclic epoxy resins. But it can be used in combination.

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 phenol compounds include phenols such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F,
Or a resin obtained by condensing naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene and aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde and salicylaldehyde under an acidic catalyst, polyparavinylphenol resin, There are phenol-aralkyl resins having a xylylene group synthesized from phenols and dimethoxyparaxylene, and may be used alone or in combination of two or more. The equivalent ratio of the epoxy resin (A) to the curing agent (B) is 0.7 to 0.7% in order to minimize the unreacted components.
It is preferable to set it in the range of 1.3.

[0007] As the curing accelerator for promoting the reaction between the epoxy resin (C) component and the curing agent used in the present invention, general ones can be widely used, and particularly, a phenol compound is used as the curing agent. As the curing accelerator in this case, for example, 1,8-diazabicyclo (5,4,
0) diazabicycloalkenes such as undecene-7 and derivatives thereof, tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol and tris (dimethylaminomethyl) phenol, 2-methylimidazole, -Phenylimidazole, 2-phenyl-4-methylimidazole,
Imidazoles such as 2-heptadecyl imidazole, organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, triphenylphosphonium-triphenylborane, triphenylphosphine-benzoquinone adduct, and triparatolylphosphine-benzoquinone adduct And tetraphenylboron salts such as tetraphenylphosphonium / tetrasubstituted borate such as tetraphenylphosphonium / tetraphenylborate, 2-ethyl-4-methylimidazole / tetraphenylborate, and N-methylmorpholine / tetraphenylborate. Alternatively, they can be used in combination. Among them, diazabicycloalkenes such as 1,8-diazabicyclo (5,4,0) undecene-7 and derivatives thereof are preferable in terms of the balance of properties.

Further, it is necessary to use an inorganic filler as the filler from the viewpoint of reducing the hygroscopicity and improving the strength. As the inorganic filler, fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate,
One or more powders of silicon carbide, boron nitride, beryllia, zirconia, or the like, or spherical beads, potassium titanate, silicon carbide, silicon nitride, single crystal fibers of alumina, etc., and one or more kinds of glass fibers may be blended. it can. Further, zinc borate is mentioned as an inorganic filler having a flame-retardant effect, and these can be used alone or in combination. The amount of the inorganic filler is preferably 70% by weight or more from the viewpoints of hygroscopicity, reduction of linear expansion coefficient and improvement of strength. Among the above-mentioned inorganic fillers, fused silica is preferred from the viewpoint of reducing the linear expansion coefficient, and alumina is preferred from the viewpoint of high thermal conductivity,
The shape of the filler is preferably spherical from the viewpoint of fluidity during molding and mold wear. Other additives include release agents such as higher aliphatic, higher fatty acid metal salts, ester waxes, polyolefin waxes, coloring agents such as carbon black, epoxy silane, amino silane, ureido silane, vinyl silane, alkyl silane, and organic titanate. And a coupling agent such as aluminum alcoholate. Among the above coupling agents, aminosilane is preferred from the viewpoint of flame retardancy and curability, and among them, γ-anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane, γ-anilinopropylmethyldimethoxysilane And γ-anilinopropylmethyldiethoxysilane are particularly preferred from the viewpoints of adhesion to a lead frame, moisture resistance, and moldability.

The metal hydrate which is an essential component (D) includes hydrates of aluminum, magnesium, calcium, nickel, iron, copper and the like, and hydrates of composite metals such as zinc borate and zinc stannate. No. Among them, aluminum hydroxide is preferably used. The metal hydrate has an average particle size of 14 to 25 μm, and a ratio of particles of 10 μm or less is 30% by weight or less, and a ratio of particles of 5 μm or less is 5% by weight or less. Used. Particularly preferably, those having an average particle size of 14 to 25 μm and a ratio of particles having a particle size of 10 μm or less being 10% by weight or less and a ratio of particles having a particle size of 5 μm or less being 1% by weight or less are used. The average particle size referred to here is a particle size at which the integrated weight becomes 50% in a particle size distribution measured by a laser diffraction method.
In the particle size distribution measured by the laser diffraction method also for the ratio of the following particles, the integrated weight% under each particle size
Say It is more preferable to use a metal hydrate that has been surface-treated with stearic acid, a silane coupling agent, polyamide, or the like. The compounding amount of the metal hydrate is preferably 5 to 40% by weight of the whole composition. If it is less than 5% by weight, sufficient flame retardancy cannot be obtained, and if it is more than 40% by weight, problems are likely to occur in curability and fluidity. 10-30
A range of weight% is particularly preferred.

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 general method of preparing a molding material using the above-mentioned raw materials, after a raw material mixture of a predetermined compounding amount is sufficiently mixed by a mixer or the like, kneaded by a hot roll, an extruder, or the like, cooled, pulverized, By doing so, 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 performed by a method such as injection molding, compression molding and casting. Is also possible. The epoxy resin composition manufactured using the above-mentioned means is environmentally friendly because it does not contain a brominated flame retardant or an antimony compound, and has excellent moldability and reliability, and is suitable for sealing of transistors, ICs, LSIs, and the like. Can be used.

[0012]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. Particle size adjustment of metal hydrate The particle size was adjusted to the following particle size by sieving using aluminum hydroxide CL-310 manufactured by Sumitomo Chemical Co., Ltd. * 1 By laser diffraction method

Examples 1 to 5 Comparative Examples 1 to 6 First, various materials shown in Table 1 were used, and after premixing (dry blending) each material, the material was mixed with a biaxial roll (roll surface temperature about 80 ° C.). The mixture was kneaded for 5 minutes, cooled and pulverized to produce the product.

[0014]

[Table 1]

[0015]

[Table 2]

Using a transfer molding machine, the sealing material was used at a mold temperature of 180 ° C., a molding pressure of 70 kgf / cm ² ,
Each test was performed under the condition of a curing time of 90 seconds. Spiral flow was measured by EMMI1-66. 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), the moisture resistance was evaluated. The semiconductor device used for measuring the moisture resistance was SOP-
28 pins, 85 ° C / 85RH% for 72 hours, moisture resistance +
After pretreatment at 215 ° C./90 seconds (VPS), PCT (12
(1 ° C./2 atm), and the presence or absence of disconnection of wiring on the chip was evaluated. The semiconductor device used for high-temperature storage is SOP-
The number of pins was 28, and the bonding strength of the gold wire after standing at 175 ° C. for a predetermined time was measured and judged. Table 3 summarizes the above test results. The examples according to the present invention exhibited more excellent characteristics than the comparative examples.

[0017]

[Table 3]

[0018]

The present invention relates to an epoxy resin composition for semiconductor encapsulation containing an epoxy resin, a phenol curing agent and an inorganic filler as main components, wherein a metal hydrate having a specific particle size as a flame retardant is used as an essential component. By blending, it is possible to provide a molding material which is excellent in moldability and reliability and has extremely small influence on the environment. In addition, by sealing a semiconductor element using this molding material, a semiconductor device having excellent reliability and flame retardancy can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) H01L 23/29 H01L 23/30 R 23/31 (72) Inventor Junichi Chihama 1772 Shikakubo, Yuki-shi, Ibaraki Pref. -1 F-term in Shimodate Plant, Hitachi Chemical Co., Ltd. (reference) FA048 FA088 FB097 FB237 FB267 FD018 FD030 FD090 FD137 FD14X FD156 FD160 FD200 GJ02 GQ00 4J036 AD04 AD08 AD21 AF06 AF07 AH07 AH20 AJ09 AK01 DA01 DA02 DA04 DC02 DC12 DC13 DC41 DC46 FA01 EB07 EA01 FB07 FA02 FA04 EB09 EB12 EB16 EC20

Claims (6)

[Claims] (1) an epoxy resin (B) a curing agent (C) a curing accelerator (D) a metal hydrate and (E) an inorganic filler are essential components, and the metal hydrate of (D) is Central particle size 14-2
30% by weight of particles of 5 μm and 10 μm or less
An epoxy resin composition for encapsulating a semiconductor, wherein the proportion of particles having a particle size of 5 μm or less is 5% by weight or less. 2. The metal hydrate of (D) has a center particle diameter of 14 to 2
10% by weight of particles having a size of 5 μm and 10 μm or less
The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the proportion of particles having a particle size of 5 µm or less is 1% by weight or less. 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the surface of the metal hydrate (D) is coated with a coupling agent, stearic acid, or polyamide. object. 4. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the metal hydrate (D) is aluminum hydroxide. 5. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the curing accelerator (C) is a diazabicycloalkene or a derivative thereof. 6. A resin-encapsulated semiconductor device obtained by encapsulating a semiconductor element using the epoxy resin composition for encapsulation according to any one of claims 1 to 5.