JP3413923B2 - Epoxy resin composition for semiconductor encapsulation and resin-encapsulated semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation which is excellent in solder heat resistance, moisture resistance reliability and fluidity, and a resin encapsulation type semiconductor device comprising the epoxy resin composition.

[0002]

2. Description of the Related Art Epoxy resins are excellent in heat resistance, moisture resistance, electrical characteristics, adhesiveness, etc., and can be given various characteristics by blending formulation, so they are used as industrial materials such as paints, adhesives and electrical insulation materials. Has been done.

For example, as a method of sealing electronic circuit parts such as semiconductor devices, hermetic seals made of metal or ceramics and phenol resin, silicone resin, etc. have hitherto been used.
Resin encapsulation with an epoxy resin or the like has been proposed. However, resin sealing with an epoxy resin is mainly used from the viewpoint of the balance of economy, productivity and physical properties.

In recent years, densification and automation have also been promoted in mounting components on a printed circuit board. Instead of the conventional "insertion mounting method" in which lead pins are inserted into holes in the substrate, components are soldered to the surface of the substrate. "Surface mounting method" has become popular. Along with this, the package is shifting from the conventional DIP (dual in-line package) to a thin FPP (flat plastic package) suitable for high-density mounting and surface mounting.

With the shift to the surface mounting system, the soldering process, which has not been a problem so far, has become a big problem. In the conventional pin insertion mounting method, the lead portion is only partially heated in the soldering process, but in the surface mounting method, the entire package is immersed in a heating medium and heated. As the soldering method in the surface mounting method, immersion in a solder bath, heating with saturated vapor of inert gas (vapor phase method)
Although an infrared reflow method or the like is used, the whole package is heated to a high temperature of 210 to 270 ° C. by either method. Therefore, the package sealed with the conventional sealing resin has a problem that the resin part is cracked during soldering or peeling occurs between the chip and the resin, which reduces reliability and cannot be used as a product. Occurs.

The occurrence of cracks in the soldering process is
It is said that the moisture absorbed between the post-curing and the mounting process explosively vaporizes and expands during soldering heating.As a countermeasure against this, the post-cured package is completely dried and sealed. The method of storing and shipping is used.

Various improvements have been made to the sealing resin. For example, a method of blending a novolac type epoxy resin and a phenol aralkyl resin with a matrix resin (Japanese Patent Laid-Open No. Sho 53-53).
-299, JP-A-59-67660), and a method of blending a matrix resin with a biphenyl type epoxy resin and a phenol aralkyl resin in an amount of 60 to 85% by weight (JP-A-3-207714, JP-A-4-207714). 487
No. 59, Japanese Patent Laid-Open No. 4-55423) and the like have been proposed.

[0008]

However, the method of enclosing the dry package in the container has a drawback that the manufacturing process and the handling work of the product are complicated and the product price is high.

Further, resins improved by various methods have been gradually effective, but they are not yet sufficient. A method of blending a novolac type epoxy resin and a phenol aralkyl resin with a matrix resin (Japanese Patent Laid-Open No. Sho 53-53
-299, JP-A-59-67660), and a method of blending a matrix resin with a biphenyl type epoxy resin and a phenol aralkyl resin in an amount of 60 to 85% by weight (JP-A-3-207714, JP-A-4-207714). 487
In Japanese Patent Laid-Open No. 59 and Japanese Patent Laid-Open No. 4-55423), not only the melt viscosity of the matrix resin is high and there is a problem in the filling property, but also cracking of the resin portion during soldering is not sufficient.

An object of the present invention is to solve the problem of resin cracks that occur during the soldering process, to prevent deterioration of reliability, and to have good flow, that is, semiconductor encapsulation excellent in solder heat resistance, moisture resistance reliability and fluidity. An epoxy resin composition for use and a resin-sealed semiconductor device having excellent solder heat resistance and moisture resistance reliability.

[0011]

Means for Solving the Problems The inventors of the present invention used an epoxy resin having a biphenyl skeleton and a curing agent having a naphthol skeleton as a matrix resin, and used 86 to 95 as a filler.
The present invention has been accomplished by finding that the above-mentioned problems can be achieved and that an epoxy resin composition and a resin-encapsulated semiconductor device that meet the purpose can be obtained by adding them in a weight percentage.

That is, the present invention relates to an epoxy resin (A),
An epoxy resin composition comprising a curing agent (B) and a filler (C), wherein the epoxy resin (A) has the following general formula (I):

[Chemical 5] (In the formula, R ^{1 to} R ⁸ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a halogen atom.) The epoxy resin (a) having a skeleton represented by the formula is contained as an essential component, and The curing agent (B) has the following general formula (II)

[Chemical 6] (In the formula, n represents an integer of 0 to 10.) The naphthol compound (b) having a skeleton represented by the formula is contained as an essential component, and the naphthol compound (b) has a softening point of 10
Unreacted monomer is 0% or less, the unreacted monomer is 1% by weight or less of the naphthol compound (b), and the proportion of the filler (C) is 86 to 95% by weight based on the whole semiconductor encapsulation. A stopping epoxy resin composition and a resin-encapsulated semiconductor device comprising the epoxy resin composition.
Hereinafter, the configuration of the present invention will be described in detail.

The epoxy resin (A) in the present invention is an epoxy resin (a) having a skeleton represented by the above formula (I).
Is important as an essential component. If the epoxy resin (a) is not contained, the effect of preventing the occurrence of cracks in the soldering process is not exerted.

In the above formula (I), preferred specific examples of R ^{1 to} R ⁸ are 4,4'-bis (2,3-epoxypropoxy) biphenyl and 4,4'-bis (2,3-).
Epoxypropoxy) -3,3 ', 5,5'-tetramethylbiphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3', 5,5'-tetramethyl-2-
Chlorobiphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetramethyl-2
-Bromobiphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetraethylbiphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3 Examples include ′, 5,5′-tetrabutylbiphenyl, 4,4′-bis (2,3-epoxypropoxy) biphenyl, 4,4′-bis (2,3-epoxypropoxy) -3,3 ′. , 5,5'-Tetramethylbiphenyl is particularly preferred.

The epoxy resin (A) in the present invention is the epoxy resin (a) together with the above epoxy resin (a).
Epoxy resins other than can be used in combination.

Other epoxy resins that can be used in combination include, for example, cresol novolac type epoxy resins, phenol novolac type epoxy resins, various novolac type epoxy resins synthesized from bisphenol A, resorcin, etc., alicyclic epoxy resins, heterocyclic compounds. Examples thereof include epoxy resins and halogenated epoxy resins.

The proportion of the epoxy resin (a) contained in the epoxy resin (A) is not particularly limited, but in order to exert a more sufficient effect, the epoxy resin (a) is required.
The epoxy resin (A) should be contained in an amount of 50% by weight or more, preferably 70% by weight or more.

In the present invention, the compounding amount of the epoxy resin (A) is usually 2 to 7% by weight, preferably 2 to 5% by weight. If the compounding amount of the epoxy resin (A) is less than 2% by weight, the moldability is insufficient, which is not preferable.

The curing agent (B) in the present invention is a naphthol compound having a skeleton represented by the above formula (II),
Moreover, the softening point of the naphthol compound is 100 ° C. or lower, and the unreacted monomer is 1% by weight of the naphthol compound.
It is important to contain the following naphthol compound (b) as an essential component. When the naphthol compound (b) is not contained, the effect of improving the solder heat resistance and the effect of improving the moisture resistance reliability are not sufficiently exerted.

The softening point of the naphthol compound (b) is 100.
It is below ℃. The softening point of the naphthol compound (b) is 10
If the temperature is higher than 0 ° C., it is difficult to improve the solder heat resistance by increasing the filling amount of the filler, and sufficient flow characteristics cannot be obtained.

The amount of unreacted monomer contained in the naphthol compound (b) is 1% by weight or less of the naphthol compound. If the amount of the unreacted monomer is 1% by weight or more, it may cause deterioration of curing characteristics during transfer molding and deterioration of moisture resistance reliability.

Further, the curing agent (B) in the present invention may contain a curing agent other than the naphthol compound (b) in combination with the naphthol compound (b). Examples of curing agents that can be used in combination include phenol novolac resins, cresol novolac resins, various novolac resins synthesized from bisphenol A and resorcin, various polyhydric phenol compounds, maleic anhydride,
Examples thereof include acid anhydrides such as phthalic anhydride and pyromellitic anhydride, and aromatic amines such as metaphenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone. Of these, phenol novolac resin is preferable from the viewpoint of moisture resistance reliability.

The proportion of the naphthol compound (b) contained in the curing agent (B) is not particularly limited, and the effect of the present invention is exhibited if the naphthol compound (b) is contained as an essential component. In order to exert a sufficient effect, the curing agent (B) preferably contains the naphthol compound (b) in an amount of 50% by weight or more, and further 70% by weight or more.

In the present invention, the compounding amount of the curing agent (B) is usually 2 to 7% by weight, preferably 2 to 5% by weight. Further, the compounding ratio of the epoxy resin (A) and the curing agent (B) is such that the chemical equivalent ratio of (B) to (A) is 0.5 to 1.5, especially from the viewpoint of mechanical properties and moisture resistance reliability. 0.8 ~
It is preferably in the range of 1.2.

Further, in the present invention, the epoxy resin (A)
A curing catalyst may be used to accelerate the curing reaction of the curing agent (B). The curing catalyst is not particularly limited as long as it accelerates the curing reaction, and 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 (acetylacetonato) zirconium, tri (acetylacetonato) aluminum and triphenylphosphine, trimethylphosphine,
Examples thereof include organic phosphine compounds such as triethylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine and tri (nonylphenyl) phosphine. Among them, 1,8-diazabicyclo (5,4,0) undecene-7 is particularly preferably used from the viewpoint of reactivity. Two or more kinds of these curing catalysts may be used in combination depending on the use, and the addition amount thereof is the epoxy resin (A) 10
The range of 0.1 to 10 parts by weight is preferable with respect to 0 parts by weight.

As the filler (C) in the present invention, fused silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, antimony oxide, asbestos, glass fiber, etc. Among them, fused silica is preferably used because it has a large effect of lowering the linear expansion coefficient and is effective in reducing stress.

The shape and particle size of the filler (C) are not particularly limited, but 99 to 50% by weight of spherical fused silica having an average particle size of 5 μm to 30 μm and 1 to 50% by weight of spherical fused silica having an average particle size of 3 μm or less. From the viewpoint of fluidity and solder heat resistance, it is preferable that the filler (C) contains the fused silica (c) of 50 wt% or more, preferably 70 wt% or more, and more preferably 90 wt% or more.

Among fused silica (c), the average particle size is 5
99 to 50% by weight of spherical fused silica having a particle diameter of μm or more and 15 μm or less, particularly 95 to 70% by weight, and 1 to 50% by weight, particularly 5 to 30% by weight of spherical fused silica having an average particle size of 3 μm or less, particularly 0.1 μm or more and 2 μm or less. Spherical fused silica (c
′) Is particularly preferable.

The average particle size as used herein means a particle size (median size) at which the cumulative weight becomes 50%, and the average particle size is different.
When more than one kind of crushed or spherical fused silica is used in combination, it means the average particle size of the crushed or spherical fused silica of the mixture.

In the present invention, the proportion of the filler (C) is 86 to the whole from the viewpoint of solder heat resistance, moldability and low stress.
It is 95% by weight, preferably 88 to 93% by weight.

In the present invention, it is preferable in terms of reliability that the filler is surface-treated in advance with a coupling agent such as a silane coupling agent or a titanate coupling agent. As the coupling agent, silane coupling agents such as epoxysilane, aminosilane, mercaptosilane and the like are preferably used. Among them, it is particularly preferable to use aminosilane from the viewpoint of fluidity.

The epoxy resin composition of the present invention includes halogen compounds such as halogenated epoxy resins, flame retardants such as phosphorus compounds, flame retardant aids such as antimony trioxide, colorants such as carbon black and iron oxide, and silicone rubber. , Olefin copolymers, modified nitrile rubber, modified polybutadiene rubber, modified silicone oil and other elastomers,
Thermoplastic resins such as polyethylene, long-chain fatty acids, metal salts of long-chain fatty acids, esters of long-chain fatty acids, amides of long-chain fatty acids, mold release agents such as paraffin wax, and crosslinking agents such as organic peroxides are added arbitrarily. can do.

The epoxy resin composition of the present invention is preferably melt-kneaded, for example, by melt-kneading using a known kneading method such as Banbury mixer, kneader, roll, single-screw or twin-screw extruder and cokneader. , Manufactured.

The encapsulation of the semiconductor element using the above epoxy resin composition is not particularly limited, and a molding method conventionally used, for example, transfer molding,
It can be performed by employing injection molding, casting method, or the like. In this case, the molding temperature of the epoxy resin composition is 150 to 180 ° C., and the post cure is 150 to 180 ° C.
It is preferable to carry out for 2 to 16 hours.

Here, as the semiconductor device of the present invention, D
Examples include IP type, flat back type, PLCC type, SO type, and the like, in which a semiconductor element is directly fixed to a printed wiring board or a heat sink, and a hybrid IC full mode type semiconductor device. The material of the printed circuit board is not particularly limited, and examples thereof include metal oxides, glass-based inorganic insulators, phenol, epoxy,
Paper base materials such as polyimide and polyester, glass cloth base materials,
Organic insulating materials such as glass mat substrate, polysulfone, Teflon, polyimide film, polyester film,
Examples of the metal-based substrate include a metal base substrate, a metal core substrate, and an enameled iron plate. Further, examples of the heat sink material include copper-based and iron-based metal materials.

[0036]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition,% in an Example shows weight%.

Examples 1 to 3 and Comparative Examples 1 to 3 The components shown in Tables 1, 2 and 3 were dry blended with a mixer in the composition ratios shown in Table 4. The mixture was heated and kneaded for 5 minutes using a mixing roll having a roll surface temperature of 90 ° C., cooled and pulverized to produce an epoxy resin composition for semiconductor encapsulation.

[0038]

[Table 1]

[Table 2]

[Table 3]

[Table 4] Using this composition, 1 by low pressure transfer molding method
The composition was molded under the conditions of 75 ° C. × 2 minutes, post-cured under the conditions of 180 ° C. × 5 hours, and the physical properties of each composition were measured by the following physical property measuring methods.

Solder heat resistance: 160 pin with a chip size of 12 × 12 mm and mounting a simulated element with Al vapor deposition on the surface
20 QFP are molded and post-cured, 85 ℃ / 8
After humidifying at 5% RH for 72 hours, heat treatment was performed in an IR reflow furnace having a maximum temperature of 240 ° C., and the presence or absence of peeling between the chip and the resin interface was examined with an ultrasonic flaw detector. As the failure rate, the rate of QFP in which peeling occurred was determined.

Moisture resistance reliability: Using QFP after evaluation of solder heat resistance, under PCT conditions of 121 ° C./100% RH, the time at which the cumulative failure rate becomes 50% when the disconnection of the Al wiring becomes a failure was determined as the life.

Fillability: 160 pinQ after evaluation of solder heat resistance
After molding, the FP was observed visually and using a microscope to check whether or not it was unfilled.

Water absorption rate: 160 pi used for solder heat resistance test
The water absorption rate in nQFP was measured.

Table 5 shows the results of these evaluations.

[0044]

[Table 5] As shown in Table 5, the epoxy resin compositions (Examples 1 to 3 ) of the present invention are excellent in solder heat resistance, moisture resistance reliability, and filling property. On the other hand, Comparative Example 1 in which the epoxy resin (a) of the present invention is not contained in the epoxy resin (A) and Comparative Example 2 in which the curing agent (b) of the present invention is not contained in the curing agent (B) are solder heat resistance. Inferior in resistance, moisture resistance and filling property.

Comparative Example 3, in which the amount of the filler added was less than 86% by weight, was inferior in solder heat resistance and moisture resistance reliability, although the epoxy resin and the curing agent of the present invention were used.

[0046]

The epoxy resin composition for semiconductor encapsulation of the present invention comprises a bifunctional epoxy resin having a specific structure in the epoxy resin, a low-viscosity curing agent having a specific structure in the curing agent, and filler filling. Since the amount is as high as 86 to 95% by weight, it is excellent in solder heat resistance, moisture resistance reliability and fluidity. Further, the resin-encapsulated semiconductor device of the present invention is excellent in solder heat resistance and moisture resistance reliability.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01L 23/31 (56) References JP-A-4-173828 (JP, A) JP-A-63-99224 (JP, A) Special features Kaihei 5-125157 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 59/22 C08G 59/62 C08K 3/00 C08L 63/00-63/10 H01L 23/29

Claims (3)

(57) [Claims] 1. An epoxy resin composition comprising an epoxy resin (A), a curing agent (B) and a filler (C),
The epoxy resin (A) has the following general formula (I): (In the formula, R ^{1 to} R ⁸ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a halogen atom.) The epoxy resin (a) having a skeleton represented by the formula is contained as an essential component, and The curing agent (B) has the following general formula (II): (In the formula, n represents an integer of 0 to 10.) The naphthol compound (b) having a skeleton represented by the formula is contained as an essential component, and the naphthol compound (b) has a softening point of 10
Unreacted monomer is 0% or less, the unreacted monomer is 1% by weight or less of the naphthol compound (b), and the proportion of the filler (C) is 86 to 95% by weight based on the whole semiconductor encapsulation. Stopping epoxy resin composition. 2. The epoxy resin (a) represented by the formula (I) is 4,4′-bis (2,3-epoxypropoxy) biphenyl and / or 4,4′-bis (2,3).
-Epoxypropoxy) -3,3 ', 5,5'-tetramethylbiphenyl, The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein 3. An epoxy resin composition comprising an epoxy resin (A), a curing agent (B) and a filler (C),
The epoxy resin (A) has the following general formula (I): (In the formula, R ^{1 to} R ⁸ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a halogen atom.) The epoxy resin (a) having a skeleton represented by the formula is contained as an essential component, and The curing agent (B) has the following general formula (II): (In the formula, n represents an integer of 0 to 10.) The naphthol compound (b) having a skeleton represented by the formula is contained as an essential component, and the naphthol compound (b) has a softening point of 10
Epoxy resin at 0 ° C. or lower, the unreacted monomer is 1% by weight or less of the naphthol compound (b), and the proportion of the filler (C) is 86 to 95% by weight of the whole. A resin-encapsulated semiconductor device, which is encapsulated with a composition.