JP2000336243A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellent in flame retardancy, curability, adhesion and high-temperature reliability by using as the constituents an epoxy resin, a curing agent, a filler, and a phosphorus compound having a phosphorus atom of a specified valence directly bonded to a carbon atom. SOLUTION: The resin composition contains 0.5-20 wt.% epoxy resin represented by formula I, such as 4,4'-bis(2,3-epoxypropoxy)biphenyl, 0.5-20 wt.% curing agent represented by formula II, such as a phenol aralkyl resin, with the chemical equivalent ratio of the curing agent to the epoxy resin being (0.5 to 1.5):1,75-97 wt.% filler comprising an amorphous silica with a mean particle diameter of 3-40 μm, and a phosphorus compound with a mean particle diameter of 2-50 μm, in an amount of 0.01-10 wt.% in terms of phosphorus atoms based on the components except for the filler. The phosphorus compound used comprises a compound having a structure represented by formula I or formula II wherein a pentavalent phosphorus atom is directly bonded to at least one carbon atom. In the formulas, R1 to R8 are each H or a 1-4C alkyl; n is 1 to 3; X1 is an aryl or the like; X2 is alkyl or the like; and R is H, amino, hydroxy or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to flame retardant, curable,
The present invention relates to an epoxy resin composition having excellent adhesion and high-temperature reliability, and more particularly to an epoxy resin composition for semiconductor encapsulation and a semiconductor device.

[0002]

2. Description of the Related Art As a method of sealing an electronic circuit portion such as a semiconductor device, a sealing resin comprising an epoxy resin, a curing agent, and an inorganic filler is used in view of the balance between economy, productivity, and physical properties. Resin sealing has become common. As semiconductor devices become thinner and higher in density in recent years, required characteristics such as moldability and reliability of a sealing resin are increasing.

Further, these electronic components such as semiconductors include:
In order to ensure safety, provision of flame retardancy is required by UL standards. Therefore, conventional sealing resins have been added with a halide-based flame retardant such as a brominated epoxy resin as a flame retardant and an antimony compound such as antimony trioxide as a flame retardant aid.

However, these flame retardants and flame retardant auxiliaries not only cause a decrease in the reliability of the semiconductor, but also generate halogen gas at the time of burning, and contain a flame retardant and a flame retardant auxiliaries. There is a problem of waste disposal of resin.

To solve the above problems, the inventors have already proposed in Japanese Patent Application Laid-Open No. 9-235449 to add a phosphorus-based flame retardant.

However, in order to ensure flame retardancy with a phosphorus-based flame retardant (phosphate ester compound) without using a conventional flame retardant or flame retardant auxiliary agent, a phosphorus-based flame retardant (P It is necessary to mix a large amount of a phosphoric acid ester compound), and there is a demand for a further improvement in curability, adhesion, solder heat resistance, and the like.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a semiconductor flame-retardant which is excellent in flame retardancy, curability, adhesion, and high-temperature reliability and does not contain a conventional flame retardant, ie, a halide flame retardant or antimony oxide. It is an object to provide an epoxy resin composition.

[0008]

In order to solve such a problem, the present invention mainly has the following configuration. That is,
"Epoxy resin (A), curing agent (B), filler (C),
An epoxy resin composition containing a phosphorus compound (D), wherein the phosphorus compound (D) has a pentavalent phosphorus atom and is directly bonded to at least one carbon atom (d ). An epoxy resin composition comprising: ".

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail.
In the present invention, “weight” means “mass”.

The epoxy resin (A) in the present invention is not particularly limited as long as it has a plurality of epoxy groups in the molecule. Specific examples thereof include cresol novolak epoxy resin, phenol novolak epoxy resin, biphenyl Epoxy resin, bisphenol A
Epoxy resin, bisphenol F epoxy resin, various novolak epoxy resins synthesized from bisphenol A and resorcin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin and Halogenated epoxy resins are exemplified. In the epoxy resin (A), two or more epoxy resins can be used in combination.

Among these epoxy resins, those which are particularly preferably used in the present invention are biphenyl type epoxy resins having a skeleton represented by the following general formula (III) because of their excellent solder heat resistance.

[0012]

Embedded image (However, R ^{1 to} R ⁸ in the formula represent a hydrogen atom and an alkyl group having 1 to 4 carbon atoms.)

The epoxy resin (A) in the present invention preferably contains at least 50% by weight, more preferably at least 70% by weight of a biphenyl type epoxy resin having a biphenyl skeleton having a skeleton represented by the above formula (III).

Preferred specific examples of the biphenyl type epoxy resin represented by the above formula (III) include 4,4'-bis (2,3-epoxypropoxy) biphenyl 4,4'-bis (2,3-epoxy) Propoxy) -3,3 ', 5,5'-tetramethylbiphenyl 4,4'-bis (2,3-epoxypropoxy) -3,3', 5,5'-tetraethylbiphenyl 4,4'-bis ( 2,3-epoxypropoxy) -3,3 ', 5,5'-tetrabutylbiphenyl and the like, and they are sufficiently effective when used alone or in a mixed system.

In the present invention, the amount of the epoxy resin (A) is usually 0.5 to 20% by weight, more preferably 2 to 10% by weight in the epoxy resin composition from the viewpoint of moldability and adhesion. is there. By setting the content within the above range, the moldability and the adhesiveness are sufficient, and there is no hindrance to lowering the stress due to an increase in the coefficient of linear expansion of the cured product.

The curing agent (B) in the present invention is not particularly limited as long as it reacts with the epoxy resin (A) to cure. Usually a compound having a phenolic hydroxyl group,
Compounds having acid anhydrides, amines and the like are used. Among these, specific examples of the phenolic curing agent, that is, the compound having two or more phenolic hydroxyl groups in the molecule include, for example, phenol novolak resin, cresol novolak resin, phenol aralkyl resin, bisphenol A, resorcin, and the like. Examples include various novolak resins, various polyhydric phenol compounds such as tris (hydroxyphenyl) methane and dihydrobiphenyl, and polyvinyl phenol.

Examples of the compound having an acid anhydride include maleic anhydride, phthalic anhydride, pyromellitic anhydride and the like.

Examples of the amines include aromatic amines such as metaphenylenediamine, di (aminophenyl) methane (commonly called diaminodiphenylmethane) and diaminodiphenylsulfone. For semiconductor encapsulation, a phenolic curing agent is preferably used from the viewpoint of excellent heat resistance, moisture resistance and storage stability, and two or more curing agents may be used in combination depending on the application.

Among these curing agents (B), those which are particularly preferably used in the present invention include phenol aralkyl resins represented by the following general formula (IV) because of their low water absorption and excellent solder heat resistance. Can be Further, the phenol aralkyl resin is preferably contained in the curing agent (B) in an amount of 50% by weight or more.

[0020]

Embedded image (Where n is an integer and n is 1 to 3
In the present invention, the amount of the curing agent (B) is usually 0.5 to 20% by weight, preferably 1 to 10% by weight.
% By weight. Furthermore, the mixing ratio of the epoxy resin (A) and the curing agent (B) is such that the chemical equivalent ratio of the curing agent (B) to the epoxy resin (A) is 0.5 to 1 in view of mechanical properties and moisture resistance reliability. 0.5, particularly preferably in the range of 0.8 to 1.2.

In the present invention, a curing catalyst may be used to accelerate the curing reaction between the epoxy resin (A) and the curing agent (B). The curing catalyst is not particularly limited as long as it promotes the curing reaction. For example, 2-methylimidazole,
Imidazole compounds such as 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, triethylamine, benzyldimethylamine, α-methylbenzyl Tertiary amine compounds such as dimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,0) undecene-7, zirconium tetra Organometallic compounds such as methoxide, zirconium tetrapropoxide, tetrakis (acetylaceto) zirconium, tri (acetylaceto) aluminum and triphenylphosphine, trimethylphosphine, triethylphosphine, trib Le phosphine, tri (p- methylphenyl) phosphine, an organic phosphine compound such as tri (nonylphenyl) phosphine. Among them, an organic phosphine compound is preferably used because of its excellent moisture resistance. Two or more of these curing catalysts may be used in combination depending on the application, and the addition amount thereof is preferably in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the epoxy resin (A).

As the filler (C) in the present invention, amorphous silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, antimony oxide, asbestos, glass Fibers and the like can be mentioned, and among them, amorphous silica is preferable as the filler of the present invention because it has a large effect of lowering the linear expansion coefficient and is effective in reducing stress.

The amorphous silica used in the present invention is different from crystalline silica in that it is amorphous silica in which silicon and oxygen atoms constituting the silica are not regularly arranged and are not in a crystalline state. is there. Amorphous silica can be obtained, for example, by melting crystalline silica and then rapidly cooling it (fused silica). Amorphous silica has a smaller coefficient of linear expansion than crystalline silica and is effective in reducing stress.

The amorphous silica can be produced by a known production method. For example, a method of melting crystalline silica,
Examples include a method of synthesizing from various raw materials.

The shape and particle size of the filler (C) in the present invention are not particularly limited, but the average particle size is 3 μm or more and 4 or more.
It is preferable that the filler (C) contains 50% by weight or more of spherical particles having a particle size of 0 μm or less from the viewpoint of excellent fluidity.

The average particle size referred to here is a cumulative weight of 50%
(Median diameter). In the present invention, the proportion of the inorganic filler (C) is from 75 to 9 based on the entire resin composition in view of flame retardancy, moldability (flowability) and low stress.
It is 7% by weight, preferably 80-95% by weight, more preferably 85-93% by weight.

In the present invention, it is preferable from the standpoint of reliability that the filler is previously surface-treated with a coupling agent such as a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent.

The phosphorus compound (D) used in the present invention is a compound containing a phosphorus atom in the molecule. The phosphorus compound usually has a trivalent or pentavalent phosphorus atom. Phosphite (Phosphite),
Phosphonite, Phosphite
hinite) and phosphine (Phosphine). On the other hand, those having a pentavalent phosphorus atom include phosphate (Phosp
hate), phosphonate (Phosphonate), phosphinate
(Phosphinate), Phosphine oxide
There is.

As the phosphorus compound (D) used in the present invention, a phosphorus compound having a pentavalent phosphorus atom and directly bonded to at least one carbon atom is preferred from the viewpoint of excellent storage stability. It is necessary to contain the compound (d).
In the case where there is no phosphorus-carbon bond, for example, only a phosphate having only a phosphorus-oxygen bond, the adhesion is reduced,
The subject of the present invention cannot be solved.

Examples of the phosphorus compound (d) in which the phosphorus atom is pentavalent and directly bonded to at least one carbon atom include phosphonate, phosphinate, phosphine oxide and the like.

In the present invention, the phosphorus atom is pentavalent,
The phosphorus compound (d) directly bonded to at least one carbon atom is preferably a compound represented by the following formula (I) or a compound having a structure represented by the following formula (II).

[0032]

Embedded image (In the formula, X ¹ represents an aryl group or an alkyl group. X ² represents a hydroxyl group, an aryl group or an alkyl group, which may be the same or different.)

[0033]

Embedded image (In the formula, X ² represents a hydroxyl group, an aryl group or an alkyl group, which may be the same or different. R represents a hydrogen, an amino group, a hydroxyl group, a phosphate group, an aryl group or an alkyl group.) Specifically, compounds represented by the following formulas (V) and (VI) are exemplified.

[0034]

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[0035]

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Further, the phosphorus compound (d) of the present invention, in which the phosphorus atom is pentavalent and is directly bonded to at least one carbon atom, has a plurality of hydroxyl groups in the molecule and forms a salt with a metal or organic substance. Preferably, it is formed.
By forming a salt, it is possible to make the composition excellent in curability. The metal and organic substance forming a salt are not particularly limited, but those which lower the reliability of the semiconductor such as sodium are not preferable.

The properties of the phosphorus compound (D) in the present invention are not particularly limited, and any of a liquid form and a solid (powder) form can be used, but the solid (powder) form is excellent in workability. Preferably, there is.

The property of the phosphorus compound (D) is solid (powder)
In the case of the shape, the maximum particle size is 150 μm or less,
It is preferably in the range of ５０50 μm. Maximum particle size is 1
If it is 50 μm or more, the gate may be clogged during molding, which is not preferable. The average particle size is 2 to 50 μm
If it is not within the range, the fluidity is undesirably reduced.

The amount of the phosphorus compound (D) used in the present invention is determined based on the amount of the phosphorus compound (D), excluding the filler (C), in the epoxy resin composition because of its excellent flame retardancy and adhesion. The amount of phosphorus atoms in (D) is preferably from 0.01 to 10% by weight, more preferably from 0.1 to 5% by weight.

The phosphorus compound (D) of the present invention
Is a phosphorus-based compound having a trivalent phosphorus atom at the time of compounding in the production of the composition, but may be a phosphorus-based compound having a pentavalent phosphorus atom by oxidation in the composition. Good.

The epoxy resin composition used in the present invention includes:
Colorants such as carbon black, ion scavengers such as hydrotalcite, elastomers such as silicone rubber, olefin copolymer, modified nitrile rubber, modified polybutadiene rubber, modified silicone oil, thermoplastic resins such as polyethylene, and long-chain fatty acids A releasing agent such as a metal salt of a long-chain fatty acid, an ester of a long-chain fatty acid, an amide of a long-chain fatty acid, paraffin wax, and a crosslinking agent such as an organic peroxide can be optionally added.

The epoxy resin composition of the present invention is preferably produced by melt kneading. For example, it is manufactured by melt-kneading using a known kneading method such as a Banbury mixer, a kneader, a roll, a single-screw or twin-screw extruder and a co-kneader.

Here, a semiconductor device is an electronic circuit (integrated circuit) formed by integrating transistors and diodes, resistors, capacitors, and the like on a semiconductor chip or substrate and wiring them.
And broadly refers to electronic components sealed with the epoxy resin composition of the present invention. Then, a semiconductor device can be obtained by sealing a semiconductor element formed of a semiconductor chip using the epoxy resin composition of the present invention.

[0044]

The present invention will be described below in detail with reference to examples. In addition, the numbers in the examples indicate% by weight.

<Examples 1 to 8, Comparative Examples 1 to 3> The components shown in Table 1 were dry-blended by a mixer at the composition ratios shown in Table 2. This was heated and kneaded for 5 minutes using a mixing roll having a roll surface temperature of 90 ° C., and then cooled and pulverized to produce an epoxy resin composition for semiconductor encapsulation.

Using this resin composition, molding was performed by low-pressure transfer molding under the conditions of 175 ° C. and a cure time of 2 minutes, and post-cured at 180 ° C. for 5 hours. The physical properties of the product were evaluated.

Flame retardancy test: 5 "x 1/2" x 1/16 "
Molded and post cured under the above conditions.
Flame retardancy was evaluated according to the L94 standard.

High temperature reliability: 16 pi with simulated element
nDIP (dual in-line package) was molded and post-cured under the above conditions. Twenty-four packaged simulated elements were left at 200 ° C., and when the resistance of the Al wiring portion on the simulated element increased by 0.2 Ω, the simulated element was determined to be defective.

Curability: A 36-pin TSOP (Small Small Outline Package) was molded for 30 shots under the above-mentioned molding conditions, and the cavity was inspected for mold contamination. If the curability was insufficient, the resin composition adhered to the mold, so that those with mold contamination were judged to be defective, and those without the stain were judged to be good.

Adhesion: A silicon chip (size 10 × 10 mm) with a polyimide coating on the surface was mounted.
Twelve 0 pin QFPs (quad flat packages) were molded under the above molding conditions, post-cured under the above conditions, and left at 121 ° C./100% RH and 2 atm.
The time until peeling occurred on the chip surface was examined. In addition, peeling was visually determined.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

Embedded image

[0054]

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[0055]

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[0056]

Embedded image

As can be seen from Table 2, the epoxy resin compositions of the present invention (Examples 1 to 8) are excellent in flame retardancy, curability, adhesion and high temperature reliability. On the other hand, Comparative Example 1 in which no flame retardant was added was inferior in flame retardancy. Comparative Example 2 containing only a phosphoric acid ester having no phosphorus-carbon bond and only a phosphorus-oxygen bond as a flame retardant is inferior in curability and adhesion, and is a conventional flame retardant and flame retardant auxiliary. Comparative Example 3, which contains a halogen-based flame retardant and antimony oxide,
It can be seen that the high-temperature reliability is inferior to the composition of the present invention.

[0058]

According to the constitution of the present invention, it is possible to provide a resin composition having excellent flame retardancy, curability, adhesion, and high-temperature reliability, and particularly useful for semiconductor encapsulation.

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Claims (8)

[Claims] 1. An epoxy resin composition containing an epoxy resin (A), a curing agent (B), a filler (C), and a phosphorus compound (D), wherein the phosphorus compound (D) is a phosphorus compound. An epoxy resin composition comprising a phosphorus compound (d) having a pentavalent atom and directly bonded to at least one carbon atom. 2. A compound in which a phosphorus compound having a pentavalent phosphorus atom and directly bonded to at least one carbon atom has a structure represented by the following formula (I) or (II): The epoxy resin composition according to claim 1, wherein Embedded image (In the formula, X ¹ represents an aryl group or an alkyl group. X ² represents a hydroxyl group, an aryl group or an alkyl group, which may be the same or different.) (In the formula, X ² represents a hydroxyl group, an aryl group or an alkyl group, which may be the same or different. R represents a hydrogen, an amino group, a hydroxyl group, a phosphate group, an aryl group or an alkyl group.) 3. The compound according to claim 1, wherein the phosphorus atom is pentavalent, and the phosphorus compound (d) directly bonded to at least one carbon atom forms a salt with a metal or an organic substance. 3. The epoxy resin composition according to 2. 4. The epoxy resin composition according to claim 1, wherein the phosphorus compound (D) is in the form of a powder and has a maximum particle size of 150 μm or less and an average particle size of 2 to 50 μm. object. 5. A component having a phosphorus atom content derived from the phosphorus compound (D) other than the filler (C) in the epoxy resin composition (epoxy resin, curing agent, catalyst, release agent, etc.) The epoxy resin composition according to any one of claims 1 to 4, wherein the content is 0.01 to 10% by weight based on the weight of the epoxy resin composition. 6. The epoxy resin composition according to claim 1, wherein the epoxy resin (A) contains a biphenyl type epoxy having a structure represented by the following formula (III). Embedded image (However, R ^{1 to} R ⁸ in the formula represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a halogen atom.) 7. The epoxy resin composition according to claim 1, wherein the curing agent (B) contains a phenol aralkyl resin having a structure represented by the following chemical formula (IV). Embedded image (Where n is an integer and n is 1 to 3
0% by weight) 8. A semiconductor device wherein a semiconductor element is sealed with the epoxy resin composition according to claim 1.