JPH0977850A - Epoxy resin composition and resin-sealed semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition which is excellent in fluidity, adhesion and moldability and useful in semiconductor sealing by using an epoxy resin and a phenol having a specific structure as essential components and adding a filler in a specific proportion. SOLUTION: This epoxy resin composition comprises (A) an epoxy resin, (B) a curing agent, preferably containing, as an essential component, a phenol having a structure of formulas I-III, bearing 2 or more aromatic groups directly bonding to hydroxyl groups and an alicyclic group between them, and (C) a filler, where the proportion of the component C is 80-95wt.% of the total composition. The component A contains a biphenyl type epoxy resin as an essential component, in an amount of >=50wt.%, while the phenol as the essential component in the component B is >=50wt.% based on the total component B. The component C preferably contains >=50wt.% of a composition comprising 99-50% of spherical amorphous silica with an average particle size of 5μm-30μm and 1-50% of spherical amorphous silica with an average particle size of <=3μm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition having excellent fluidity and adhesion, and a semiconductor device encapsulated with 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 the mounting method on the printed circuit board, the "surface mounting method" in which components are soldered to the surface of the board is becoming the main focus instead of the "insertion mounting method" in which the lead pin is inserted into the hole of the board. Along with that, the package also has a conventional D
Transition from IP (dual inline package) to thin FPP (flat plastic package) suitable for high-density mounting and surface mounting, and ultra-thin μ-
QFP (micro quad flat package)
Are being developed.

With the advent of ultra-thin packages, moldability has come to be more important than ever before in the required characteristics of the sealing resin. Up to now, the occurrence of cracks in the soldering process in the surface mounting method has been a major problem, but it is natural to solve this problem and maintain reliability, and in addition to achieving a certain level, good molding Sex has come to be required.

As a method for sealing a semiconductor element using an epoxy resin composition, a molding method which has been conventionally used,
For example, transfer molding, injection molding, casting method and the like are used. Molding temperature 150 ℃ ~
The epoxy resin composition is melted at 180 ° C. and poured into a mold. After that, the mold is removed, and post cure is generally performed at 150 ° C. to 180 ° C. for 2 to 16 hours.

In the case of an ultra-thin package, the flow portion of the resin for sealing is narrow during molding and has a complicated shape. In addition, collapse of the bonding wire foam and voids (air bubbles) due to the entrained air during flow are also serious problems. In order to solve these problems, improvement of members and optimization of molding conditions have been carried out. Although reduction of viscosity of sealing resin and improvement of flow characteristics have been studied, it has been difficult to maintain the conventional solder heat resistance and reliability, and a product sufficiently satisfying the purpose has not been obtained. .

[0008]

Therefore, there is a need to provide a resin capable of molding an ultra-thin package while maintaining solder heat resistance and reliability.

In the present invention, emphasis is placed on improving the fluidity of the sealing resin in order to improve the moldability. In addition, as one method for reducing cracks in the sealing resin during soldering, attention was paid to improvement in adhesion. That is, an object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation which is excellent in adhesiveness and fluidity.

[0010]

The present inventors have added an epoxy resin to a matrix resin and a phenol compound having a special structure as a curing agent as essential components, and a filler to the composition in an amount of 80 to 95% by weight. By doing so, the inventors have found that the above objects can be achieved and an epoxy resin composition that meets the purpose can be obtained, and the present invention has been achieved.

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 curing agent (B) has two or more aromatic groups to which a hydroxyl group is directly bonded, An epoxy containing a phenol compound (b) having an alicyclic group interposed therebetween as an essential component, and the proportion of the filler (C) is 80 to 95% by weight of the entire composition. A semiconductor device in which a semiconductor element is sealed with a resin composition and the epoxy resin composition.

The structure of the present invention will be described in detail below.

The epoxy resin (A) according to the present invention comprises 1
There is no particular limitation as long as it has two or more epoxy groups in the molecule.

For example, cresol novolak type epoxy resin, phenol novolak type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, various novolak type epoxy resins synthesized from bisphenol A, resorcinol, etc., linear aliphatic epoxy resin, fatty acid A cyclic epoxy resin, a heterocyclic epoxy resin, a halogenated epoxy resin and the like can be mentioned.

Two or more kinds of epoxy resins may be used in combination depending on the application, but it is preferable that the total amount of the biphenyl type epoxy resin is 50% or more from the viewpoint of heat resistance and moisture resistance. Examples of the biphenyl type epoxy resin are as follows. 4,4'-bis (2,3-
Epoxypropoxy) biphenyl, 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', 5,5'-tetrabutylbiphenyl, 4,4 ′ -Bis (2,3-epoxypropoxy) biphenyl and 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylbiphenyl.

In the present invention, the compounding amount of the epoxy resin (A) is preferably 2 to 12% by weight, more preferably 2 to 12% by weight in the epoxy resin composition from the viewpoint of moldability.
It is 10% by weight. Further, the above epoxy resins can be mixed and used.

The phenol compound (b) contained in the curing agent (B) is a compound having two or more aromatic groups to which a hydroxyl group is directly bonded, and an alicyclic group being interposed between the aromatic groups. Although the reason is unknown, the presence of the alicyclic group provides an effect of improving fluidity and adhesion. When there are three or more aromatic groups directly bonded to a hydroxyl group, it is sufficient that an alicyclic group is interposed between at least two aromatic groups. As the alicyclic group, those having a monocyclo structure (that is, not a bicyclo structure) are preferably used.

As such a phenol compound (b), one having the following chemical formula (III) is preferably used.

Embedded image (Wherein the hydrogen bonded to the carbon atom has 1 to 6 carbon atoms)
Which may be substituted by an aliphatic or alicyclic group of the above), and those having the following chemical formula (II) are preferably used.

[0019]

Embedded image (In the formula, hydrogen bonded to a carbon atom that does not form a methyl group may be substituted with an aliphatic or alicyclic group having 1 to 6 carbon atoms) Furthermore, the following structure (I)

[Chemical 6] The phenol compound (b) represented by is preferably used.

From the viewpoint of improving fluidity and adhesiveness, these phenol compounds (b) account for 50% of the total curing agent.
It is preferable to contain the above.

The curing agent (B) in the present invention may contain the above-mentioned phenol compound (b) and other curing agents in combination. Other curing agents that can be used in combination include, for example, phenol novolac resins, cresol novolac resins, phenol aralkyl resins, various novolac resins synthesized from bisphenol A and resorcin, resole resins, various polyphenol compounds such as polyvinylphenol, and maleic anhydride. Acid, phthalic anhydride,
Acid anhydrides such as pyromellitic anhydride and aromatic amines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone are exemplified.
Among them, phenol compounds having two or more hydroxyl groups in one molecule are preferable from the viewpoint of moisture resistance reliability, and among them, phenol novolac resins, cresol novolac resins, phenol aralkyl resins, and various novolac resins synthesized from bisphenol A and resorcin. preferable. Further, a phenol novolac resin, a cresol novolac resin and a phenol aralkyl resin are preferable, and when these phenol compounds are blended, the total amount of those blended compounds is the curing agent (B) component other than the terpene skeleton-containing phenol compound. , 50% by weight or more, and 7
It is preferably at least 0% by weight.

In the present invention, the compounding amount of the curing agent (B) is generally 1 to 10 in the epoxy resin composition.
%, More preferably 1 to 7% by weight, further preferably 1 to 5% by weight, and further preferably 1.5 to 4.5% by weight. Furthermore,
There is no particular limitation on the compounding ratio of the epoxy resin (A) and the curing agent (B), but from the viewpoint of mechanical properties and humidity resistance reliability of the cured product of the obtained epoxy resin and the semiconductor device, (B) to (A). Has a chemical equivalent ratio of 0.5 to 1.5,
In particular, it is preferably in the range of 0.8 to 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 Dimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,0) undecene-7,1,5-diazabicyclo (4,4. 3,0) tertiary amine compounds such as nonene-5, organometallic compounds such as zirconium tetramethoxide, zirconium tetrapropoxide, tetrakis (acetylacetonato) zirconium, tri (acetylacetonato) aluminum, and triphenylphosphine Emissions, trimethylphosphine, triethylphosphine, tributylphosphine, tri (p
Examples of the organic phosphine compound include -methylphenyl) phosphine, tri (nonylphenyl) phosphine, triphenylphosphine / triphenylborane, and tetraphenylphosphonium / tetraphenylborate. Among them, triphenylphosphine and 1,8-diazabicyclo (5,4,0) undecene-from the viewpoint of reactivity.
7 is particularly preferably used. Two or more kinds of these curing catalysts may be used in combination depending on the use, and the addition amount thereof is 0.1 to 10 parts with respect to 100 parts by weight of the epoxy resin (A).
A range of parts by weight is preferred.

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. Examples of the fibers include amorphous silica, and among them, amorphous silica has a large effect of lowering the linear expansion coefficient and is effective for lowering stress, and thus is preferably used. Examples of the amorphous silica include fused silica produced by melting quartz, and synthetic silica produced by various synthetic methods, and crushed or spherical ones are used.

The shape and particle size of the filler (C) are not particularly limited, but 99 to 50% by weight of spherical amorphous silica having an average particle size of 5 μm to 30 μm and spherical amorphous silica having an average particle size of 3 μm or less 1 Of 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more, in the filler (C). It is preferable in terms of fluidity and solder heat resistance of the semiconductor device.

Among the amorphous silica (c), spherical amorphous silica 99 to 50 having an average particle diameter of 5 μm or more and 15 μm or less.
% By weight, particularly 95 to 70% by weight, and an average particle size of 3 μm or less,
In particular, spherical amorphous silica having a size of 0.1 μm or more and 2 μm or less 1 to
The spherical amorphous silica composition (c ′), which comprises 50% by weight, particularly 5 to 30% by weight, 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 amorphous silica is used in combination, it means the average particle size of the crushed or spherical amorphous silica of the mixture.

In the present invention, the proportion of the filler (C) is preferably 80 to 95% by weight, more preferably 88 to 93% by weight of the epoxy resin composition from the viewpoint of solder heat resistance, moldability and low stress.

In the epoxy resin composition of the present invention,
A coupling agent such as a silane coupling agent or a titanate coupling agent can be blended with, and above all,
It is preferable in terms of reliability that the filler is surface-treated in advance with these coupling agents. As the coupling agent, a silane coupling agent in which an alkoxy group and a “hydrocarbon group having a functional group such as an epoxy group, an amino group, and a mercapto group” bonded to a silicon atom is preferably used.

The epoxy resin composition of the present invention includes a halogen compound such as a halogenated epoxy resin, a flame retardant such as a phosphorus compound, a flame retardant aid such as antimony trioxide, a colorant such as carbon black and iron oxide, and a 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, 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, preferably 50 to 50 wt.
It is produced by melt-kneading at a temperature in the range of 150 ° C.

The epoxy resin composition of the present invention is usually used for encapsulating a semiconductor in a powder or tablet state. The epoxy resin composition of the present invention is applied to a member, in which a semiconductor element is fixed to a substrate, at a temperature of, for example, 120 to 250 ° C., preferably 150 to 200 ° C. by a method such as transfer molding, injection molding, or casting method. A semiconductor device which is molded and sealed with a cured product of an epoxy resin composition is manufactured. If necessary, additional heat treatment (for example,
150 to 180 ° C., 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.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION

[0035]

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

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

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

This composition was molded by a low-pressure transfer molding method under the conditions of a molding temperature of 175 ° C., a molding time of 2 minutes, and a transfer pressure of 70 kg / cm ² , and 180 ° C.
Post-cure was performed under the condition of × 5 hours, and the physical properties and moldability of each composition and semiconductor device were measured by the following methods for measuring physical properties.

Solder heat resistance: 160p with a chip size of 12 × 12 mm and a package size of 28 × 28 mm × 3.4 mm (thickness) on which a simulated element having Al deposited on the surface is mounted.
20 pieces of inQFP (Quad Flat Package) are molded, post-cured, humidified at 85 ° C / 85% RH for 72 hours, then heat-treated in an IR reflow furnace with a maximum temperature of 245 ° C, and then an ultrasonic flaw detector is used. The presence or absence of peeling at the resin interface was examined. As the failure rate, the rate of QFP in which peeling occurred was determined.

Moisture resistance reliability: Using QFP after solder heat resistance evaluation, PCT (pressure / pressure) of 125 ° C / 100% RH
Under the (Cooker test) condition, the disconnection of the Al wiring was determined as a failure, and the time at which the cumulative failure rate was 50% was obtained and set as the life.

Water absorption: The water absorption of QFP used in the solder heat resistance test was measured.

Package fillability: The QFP used in the solder heat resistance test was visually observed immediately after molding to check for the presence of unfilled and voids. The evaluation result is × when unfilled is observed, Δ when a void having a size of 0.5 mm or more is observed, no void is found, or even if there is a void, the size is less than 0.5 mm. If there was, it was judged as ○.

Stage shift: used for solder heat resistance test 1
The 60 pin QFP was cut perpendicularly to the island surface and the cross section was observed with a microscope to determine whether stage shift occurred. The evaluation result is that when the stage is exposed on the surface of the package x, the maximum value of the distance moved from the position before molding is 50 μm when the stage is inside the package.
The above is indicated by Δ, and the case of less than 50 μm is indicated by ◯.

Adhesion: QFP2 used for solder heat resistance test
Using 0 pieces, after humidifying at 85 ° C / 85% RH for 168 hours,
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.

Table 6 shows the results of these evaluations.

[0050]

[Table 6]

As shown in Table 6, the epoxy resin compositions of the present invention (Examples 1 to 5) are excellent in solder heat resistance, moisture resistance reliability and moldability. On the other hand, curing agent (B)
Comparative Examples 2 and 3, which do not contain the phenol compound (b) of the present invention, are inferior in package filling property and moldability such as stage shift. Further, Comparative Example 4 is excellent in moldability, but is inferior in solder heat resistance, moisture resistance reliability and adhesion.

Further, Comparative Example 1 in which the amount of the filler added is less than 80% by weight is inferior in solder heat resistance and moisture resistance reliability in spite of using the curing agent of the present invention.

[0053]

The epoxy resin composition of the present invention is excellent in moldability and adhesiveness, and a semiconductor device in which a semiconductor element is sealed with the epoxy resin composition of the present invention is
Excellent solder heat resistance and moisture resistance reliability.

Claims (12)

[Claims] 1. An epoxy resin composition comprising an epoxy resin (A), a curing agent (B) and a filler (C), wherein the curing agent (B) has an aromatic group to which a hydroxyl group is directly bonded. It contains two or more phenol compounds (b) in which an alicyclic group is interposed between the aromatic groups, as an essential component, and the proportion of the filler (C) is 80 to 95% by weight in total. %
And an epoxy resin composition. 2. The phenol compound (b) has the following structure (I
II) The epoxy resin composition according to claim 1, characterized in that Embedded image (Wherein the hydrogen bonded to the carbon atom has 1 to 6 carbon atoms)
Optionally substituted by an aliphatic or alicyclic group) 3. The phenol compound (b) has the following structure (I
The epoxy resin composition according to claim 1, wherein the epoxy resin composition has I). Embedded image (In the formula, hydrogen bonded to a carbon atom that does not form a methyl group may be substituted with an aliphatic or alicyclic group having 1 to 6 carbon atoms) 4. The phenol compound (b) has the following structure (I
) The epoxy resin composition according to claim 1, which is 5. The epoxy resin composition according to claim 1, which contains the phenol compound (b) in an amount of 50% by weight or more based on the curing agent (B). 6. The epoxy resin according to claim 1, wherein the curing agent (B) contains a phenol compound having two or more hydroxyl groups in one molecule other than the phenol compounds (b) and (b). Composition. 7. The epoxy resin composition according to claim 1, wherein the epoxy resin (A) contains a biphenyl type epoxy resin as an essential component. 8. The content of the biphenyl type epoxy resin is 50% by weight or more in the epoxy resin (A).
The epoxy resin composition according to the above. 9. The filler (C) has an average particle size of 5 μm or more and 3
Amorphous silica (c) consisting of 99 to 50% by weight of spherical amorphous silica having a particle diameter of 0 μm or less and 1 to 50% by weight of spherical amorphous silica having an average particle diameter of 3 μm or less is contained in the filler (C) at 50% by weight.
The epoxy resin composition according to any one of claims 1 to 8, containing the above. 10. The epoxy resin composition according to any one of 1 to 9, which further contains triphenylphosphine or 1,8-diazabicyclo (5,4,0) undecene-7 as a curing catalyst. 11. The epoxy resin composition according to claim 1, which is used for semiconductor encapsulation. 12. A resin-encapsulated semiconductor device encapsulated with the epoxy resin composition according to claim 11.