JPH08151427A - Epoxy resin composition - Google Patents

Abstract

PURPOSE: To obtain a resin composition excellent in humidity resistance and flame retardancy and used for sealing a semiconductor by mixing an epoxy resin with a phenolic resin curing agent, a cure accelerator, a red phosphorus flame retardant, an ion scavenger and an inorganic filler. CONSTITUTION: This composition comprises an epoxy resin, a phenolic resin curing agent, a cure accelerator, a red phosphorus flame retardant, an ion scavenger and an inorganic filler. It is desirable that the red phosphorus flame retardant is one prepared by precoating the surface of red phosphorus with a phenolic resin or a mixture thereof with aluminum hydroxide. It is desirable that the content of the red phosphorus in the coated flame retardant is 60-95wt.%. When the content of the red phosphorus added is below 60wt.%, the flame ratardant needs to be added in a larger amount. When this content is above 95wt.%, the stability of the red phosphorus added is problematic. It is desirable that the red phosphorus flame retardant has a mean particle diameter of 10-70μm and a maximum particle diameter of 150μm or below.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor encapsulating epoxy resin composition having excellent flame retardancy.

[0002]

2. Description of the Related Art Conventionally, electronic parts such as diodes, transistors and integrated circuits have been encapsulated with an epoxy resin composition. In this composition, a halogen-based flame retardant alone or a combination of a halogen-based flame retardant and antimony trioxide is used as a flame retardant, and an inorganic filler such as fused silica or crystalline silica is blended as a filler. However, from the viewpoint of environmental hygiene, there is a demand for a flame-retardant epoxy resin composition that does not use a halogen-based flame retardant or antimony trioxide.

In response to this requirement, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, boron compounds, etc. have been studied, but they are practically used because they contain many impurities and cannot be effective unless they are added in large amounts. It has not been realized. Red phosphorus-based flame retardants are effective in adding a small amount and are useful for making an epoxy resin composition flame-retardant. However, red phosphorus reacts with a small amount of water to generate phosphine and corrosive phosphoric acid, so that moisture resistance is high. It cannot be used for epoxy resin compositions for semiconductor encapsulation, which have extremely strict requirements. For this reason, red phosphorus particles are coated with aluminum hydroxide, metal oxides, other inorganic compounds, organic compounds such as thermosetting resins to stabilize red phosphorus. It hasn't reached the standard yet.

[0004]

SUMMARY OF THE INVENTION In order to solve such problems, the present invention achieves flame retardancy by adding a red phosphorus flame retardant and improves moisture resistance by adding an ion scavenger.
The present invention provides a semiconductor encapsulating epoxy resin composition containing no halogen-based flame retardant and antimony trioxide.

[0005]

The present invention provides (A) epoxy resin, (B) phenol resin curing agent, (C) curing accelerator, (D) red phosphorus flame retardant, (E) ion scavenger, and (F) An epoxy resin composition for semiconductor encapsulation, which comprises an inorganic filler.

The red phosphorus-based flame retardant used in the present invention includes red phosphorus alone, but is difficult to handle because it is easily oxidized and unstable, and the red resin is a red resin or a mixture of aluminum hydroxide and phenol resin. It is preferable that the surface of phosphorus is previously coated. The content of red phosphorus in the coated flame retardant is preferably 60 to 95% by weight. If the red phosphorus content is less than 60% by weight, it is necessary to add a large amount.
If it exceeds 5% by weight, there is a problem in the stability of red phosphorus. The average particle size of the red phosphorus flame retardant is 10 to 70μ.
m, and the maximum particle size is preferably 150 μm or less. When the average particle size is less than 10 μm, the fluidity of the composition is lowered, and when it exceeds 70 μm, the dispersibility of the flame retardant is deteriorated. Further, if the maximum particle size exceeds 150 μm, there is a problem in the filling property of the package. Examples of red phosphorus flame retardants include Noval red and Nova Excel of Phosphorus Chemical Co., Ltd., which can be easily obtained from the market. The content of red phosphorus in the entire composition is preferably 0.3 to 5% by weight, and if it is less than 0.3% by weight, flame retardancy is insufficient. The red phosphorus flame retardant is flammable, and the flame retardant itself oxidizes and exhibits flame retardancy. If it exceeds 5% by weight, the flame retardant acts too much due to the excessive amount of flame retardant and thus the flame retardant property. Run out.

The ion scavenger used in the present invention reduces ionic impurities by stimulating phosphoric acid, organic acid anions, halogen anions, alkali metal cations, alkaline earth metal cations and the like. It is known that aluminum is corroded by phosphoric acid generated from red phosphorus, and it is intended to prevent the corrosion reaction of aluminum by promoting phosphoric acid. As an ion scavenger, Bi
O _X (OH) _Y (NO ₃ ) _Z [where X = 0.9 to 1.
1, Y = 0.6 to 0.8, Z = 0.2 to 0.4], Mg
_4.3 Al ₂ (OH) _12.6 CO ₃ · 3.5H ₂ O, Sb ₂ O ₅ ·
_{2H 2 O, SbSi V Bi W} O X (OH) Y (NO 3) Z · n
H ₂ O [where V = 0.1 to 0.3, W = 1.5 to
1.9, X = 4.1 to 4.5, Y = 1.2 to 1.6, Z
= 0.2~0.3, n = 1~2], and the _{like, BiO X (OH) Y (} NO 3) is a of these _Z, Mg _4.3 Al
₂ (OH) _12.6 CO ₃ .3.5H ₂ O is more preferable because it selectively captures anions, and these may be used alone or in combination. Also, these items are easily available from the market. This ion scavenger is 0.2 to 2 in the total composition.
It is preferable to contain it by weight%. This is because if it is less than 0.2% by weight, the moisture resistance is insufficient, and if it exceeds 2% by weight, the flame retardancy decreases.

The epoxy resin used in the present invention is a monomer, oligomer, or the like having two or more epoxy groups in one molecule.
It refers to polymers in general, and its molecular weight and molecular structure are not particularly limited, but examples thereof include biphenyl type epoxy compounds, bisphenol type epoxy compounds, phenol novolac type epoxy resins, cresol novolac type epoxy resins, triphenol methane type epoxy compounds, alkyls. Examples thereof include modified triphenol methane type epoxy compounds and triazine nucleus-containing epoxy resins, which may be used alone or in combination. Phenolic resin curing agent used in the present invention, the molecular weight, although not particularly limited molecular structure, for example, phenol novolac resin, cresol novolac resin, dicyclopentadiene modified phenol resin, paraxylylene modified phenol resin, terpene modified phenol resin, Examples thereof include triphenol methane compounds. Phenol novolac resins, dicyclopentadiene-modified phenol resins, paraxylylene-modified phenol resins, terpene-modified phenol resins and the like are preferable, and they may be used alone or in combination. Further, as a blending amount of these curing agents, the ratio of the number of epoxy groups of the epoxy compound and the number of hydroxyl groups of the phenol resin curing agent is 0.
8 to 1.2 is preferable.

The curing accelerator used in the present invention may be any one as long as it accelerates the curing reaction between the epoxy group and the hydroxyl group.
What is generally used as a sealing material can be widely used. Examples thereof include 1,8-diazabicycloundecene, triphenylphosphine, benzyldimethylamine and 2-methylimidazole, which may be used alone or in combination. Examples of the inorganic filler include fused silica powder, crystalline silica powder, alumina, silicon nitride and the like. The blending amount of these inorganic fillers is preferably 60 to 90% by weight based on the balance between moldability and reliability. Especially with a large amount of filler,
It is common to use spherical fused silica.

The epoxy resin composition of the present invention contains an epoxy resin, a phenol resin curing agent, a curing accelerator, a red phosphorus flame retardant, an ion scavenger and an inorganic filler as essential components.
In addition to these, various additives such as a silane coupling agent, a coloring agent such as carbon black and red iron oxide, a release agent such as natural wax and a synthetic wax, and a low stress additive such as silicone oil and rubber are appropriately added as necessary. There is no problem even if it is mixed. Further, in order to produce the encapsulating epoxy resin composition of the present invention as a molding material, after the components which are essential components and other additives are sufficiently uniformly mixed by a mixer or the like,
Further, it can be melt-kneaded with a hot roll or a kneader, cooled, and then pulverized to obtain a sealing material. These molding materials can be applied to coating, insulation, sealing, etc. of transistors, integrated circuits, etc., which are electric or electronic parts.

The present invention will be specifically described below with reference to examples. Example 1 Composition below Orthocresol novolac type epoxy resin (melting point 65 ° C., epoxy equivalent 200 g / eq) 18.3 parts by weight Phenol novolac resin curing agent (softening point 80 ° C., hydroxyl equivalent 104 g / eq) 9.5 parts by weight Parts fused silica powder (average particle size 15 μm, specific surface area 2.2 m ² / g) 68.5 parts by weight triphenylphosphine 0.2 parts by weight carbon black 0.5 parts by weight carnauba wax 0.5 parts by weight Combustion agent A (red phosphorus surface-treated with a mixture of aluminum hydroxide and phenol resin, red phosphorus content 75% by weight, average particle size 40 μm, maximum particle size 150 μm) 2.0 parts by weight Bismuth ion trapping agent _{[BiO X (OH) Y (NO} 3) Z ] 0.5 parts by weight at room temperature in a mixer, kneaded by biaxial roll at 70 to 100 ° C. Was molded material followed by cooling then pulverizing. Further, the obtained molding material was tabletted, and a low pressure transfer molding machine was used to mold a test piece for flame resistance test under the conditions of 175 ° C., 70 Kg / cm ² and 120 seconds, and 3 × 3.5 mm for humidity resistance test. The chip was encapsulated in 16 pDIP. The following moisture resistance test was performed on the sealed test element. Flame resistance test: UL-94 vertical test (sample thickness 1.0m
m), expressed as flame retardancy. Moisture resistance test: The sealed test element was subjected to a pressure cooker test (125 ° C., 100% RH) to measure the open circuit failure. Table 1 shows the test results.

Examples 2 to 7 Compounding was carried out according to the formulation shown in Table 1, and molding materials were obtained in the same manner as in Example 1. The aluminum / magnesium ion scavenger of Example 5 was Mg _4.3 Al ₂ (OH) _12.6 CO ₃
The red phosphorus flame retardant B of Example 6 was 3.5 H ₂ O, and the red phosphorus was surface-treated with a phenol resin.
5% by weight, average particle size 25 μm, and maximum particle size 150 μm. A molded product sealed with a test material was obtained from this molding material, and a flame resistance test and a moisture resistance test were conducted in the same manner as in Example 1 using this molded product. Table 1 shows the test results. Comparative Examples 1 to 7 Compounding was carried out according to the formulation of Table 2 and molding materials were obtained in the same manner as in Example 1. The brominated epoxy resin of Comparative Example 7 has a softening point of 60 ° C. and an epoxy equivalent of 360 g / eq. A molded product sealed with a test material was obtained from this molding material, and a flame resistance test and a moisture resistance test were conducted in the same manner as in Example 1 using this molded product. The test results are shown in Table 2.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

By encapsulating a semiconductor element with the composition of the present invention, it is possible to obtain a semiconductor device which does not contain a halogen-based flame retardant and antimony trioxide and has excellent moisture resistance and flame retardancy.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C08K 3/18 NKV C08L 63/00 NLD H01L 23/29 23/31

Claims (5)

[Claims] 1. (A) Epoxy resin, (B) Phenolic resin curing agent, (C) Curing accelerator, (D) Red phosphorus flame retardant,
An epoxy resin composition for semiconductor encapsulation, comprising (E) an ion scavenger and (F) an inorganic filler. 2. The red phosphorus flame retardant is red phosphorus which is a phenol resin,
Alternatively, it is coated with a mixture of aluminum hydroxide and a phenol resin, and the content of red phosphorus in the red phosphorus flame retardant is 6
The epoxy resin composition for semiconductor encapsulation according to claim 1, which is 0 to 95% by weight, has an average particle size of 10 to 70 μm, and has a maximum particle size of 150 μm or less. 3. The ion scavenger is BiO _x (OH) _Y (NO
₃ ) _Z [where X = 0.9 to 1.1 and Y = 0.6 to 0.
8, Z = 0.2 to 0.4] and / or Mg _4.3 Al ₂ (O
H) The epoxy resin composition for semiconductor encapsulation according to claim 1 or _2, which is _12.6 CO ₃ .3.5H ₂ O. 4. The content of red phosphorus in the entire composition is 0.3-5.
The epoxy resin composition for semiconductor encapsulation according to claim 1, 2 or 3, which is in weight%. 5. The content of the ion scavenger in the total composition is 0.2 to 2% by weight, claim 1, claim 2, claim 3.
Alternatively, the epoxy resin composition for semiconductor encapsulation according to claim 4.