JP2000273281A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for semiconductor sealing use free from both halogens and antimony and excellent in flame retardancy, high- temperature storage characteristics and reliability in moistureproofness. SOLUTION: This epoxy resin composition is characterized by essentially comprising (A) phenolic resin(s) containign 30-100 wt.% of novolak-type phenolic resin containing biphenyl derivative and/or naphthalene derivative in the molecule, (B) an epoxy resin, (C) a curing promoter, (D) an inorganic filler, and (E) at least one kind selected from zinc molybdate-coated fused spherical silica, zinc molybdate-coated talc, and zinc borate.

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 encapsulating a semiconductor which does not contain a halogen-based flame retardant or an antimony compound and has excellent flame retardancy and reliability, and encapsulates a semiconductor element using the same. The present invention relates to a semiconductor device comprising:

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits are mainly sealed with an epoxy resin composition. These resin compositions contain a halogen-based flame retardant and an antimony compound in order to impart flame retardancy. In response to this requirement, hydroxides such as aluminum hydroxide and magnesium hydroxide have been studied, but if not added in large amounts, the flame-retardant effect does not appear,
It has not been put to practical use because of the large amount of impurities and the problem of moisture resistance reliability. In addition, red phosphorus-based flame retardants are effective with a small amount of addition, and are useful for flame retardation of resin compositions.However, red phosphorus reacts with a small amount of water to produce phosphine and corrosive phosphoric acid. , There is a problem in the moisture resistance reliability. There is a need for a resin composition that is compatible with flame retardancy, high-temperature storage characteristics, and moisture resistance reliability and that does not use a halogen-based flame retardant or an antimony compound.

[0003]

SUMMARY OF THE INVENTION The present invention relates to an epoxy resin composition for semiconductor encapsulation which is excellent in moldability, flame retardancy, high-temperature storage characteristics, and humidity resistance, and for encapsulating a semiconductor element using the same. A semiconductor device is provided.

[0004]

The present invention comprises (A) a phenolic resin, (B) an epoxy resin, (C) a curing accelerator,
(D) an inorganic filler, (E) fused spherical silica coated with zinc molybdate, or talc coated with zinc molybdate, and at least one selected from zinc borate as essential components. In a more preferred embodiment, the phenolic resin and the epoxy resin are a novolak-type phenol resin containing a biphenyl derivative and / or a naphthalene derivative in a molecule in an amount of 30 to 100% by weight in the total phenol resin amount. % Of a phenolic resin, a novolak-type epoxy resin containing a biphenyl derivative and / or a naphthalene derivative in a molecule thereof in an amount of 30 to 100% by weight in a total epoxy resin, and a semiconductor using these resin compositions. This is a resin-sealed semiconductor device in which elements are sealed.

[0005]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, at least one selected from the group consisting of a specific phenol resin and / or a specific epoxy resin having high flame retardancy, an inorganic filler coated with zinc molybdate, and zinc borate. By combining these, a resin composition having excellent moldability, flame retardancy, high-temperature storage properties, and moisture resistance reliability has been found. The phenol resin used in the present invention is a phenol resin having a novolak structure containing a biphenyl derivative and / or a naphthalene derivative in a molecule, and the epoxy resin is an epoxy resin having a novolak structure containing a biphenyl derivative and / or a naphthalene derivative in a molecule. And a molecule of a phenol resin or an epoxy resin containing an aromatic ring of a biphenyl derivative or a naphthalene derivative. When the aromatic ring of the biphenyl derivative or the naphthalene derivative is contained in the phenol resin or the epoxy resin, the bonding energy between the molecules becomes large, and the decomposition by combustion hardly occurs, and the flame retardancy is exhibited. Anthracene, which has a larger number of aromatic rings in the molecule of the phenolic resin or epoxy resin, that is, anthracene is more difficult to burn than naphthalene, and the flame retardancy is improved, but the softening point is too high and there is a problem in fluidity. The naphthalene derivative is optimal because it has a good balance between flame retardancy and fluidity. Further, by controlling the reactivity, the flame retardancy can be further improved. That is, when the ratio of the number of phenolic hydroxyl groups of the total phenolic resin to the number of epoxy groups of the total epoxy resin is increased, the flame retardancy is further improved. This is because there is an excess hydroxyl group that does not react with the epoxy group in the resin composition, and when burning a cured product of the resin composition, an endothermic reaction occurs due to dehydration thermal decomposition of the remaining hydroxyl groups. is there. The ratio of the number of phenolic hydroxyl groups in the total phenolic resin to the number of epoxy groups in the total epoxy resin is preferably 2 or less, and if it exceeds 2, the reactivity is extremely reduced.
Further, since the water absorption rate increases and the moisture resistance reliability decreases, more preferred is 1.0 to 1.5.

The phenolic resin used in the present invention is a phenolic resin having a novolak structure containing a biphenyl derivative and / or a naphthalene derivative in the molecule. More specifically, the phenolic resin having a novolak structure containing a biphenyl derivative has the formula (1) Indicated by The phenol resin represented by the formula (1) is a resin obtained by a Friedel-Crafts alkylation reaction between phenol and bismethoxymethylbiphenyl. In the formula (1), n is 1 to 10, and n is 1
If it exceeds 0, the melt viscosity of the resin becomes too high and the fluidity decreases. In order to exhibit flame-retardant properties, it is desirable that the phenolic resin represented by the formula (1) is incorporated in the total phenolic resin in an amount of 30% by weight or more, preferably 50% by weight or more. If it is less than 30% by weight, the flame retardancy is insufficient.
A specific phenolic resin having a novolak structure containing a naphthalene derivative is represented by the formula (3). N in the equation (3) is 1
When n exceeds 10, the melt viscosity of the resin becomes too high and the fluidity decreases. In order to exhibit the flame-retardant property, it is desirable that the phenolic resin represented by the formula (3) is blended in an amount of 30% by weight or more, preferably 50% by weight or more in the total phenolic resin. If it is less than 30% by weight, the flame retardancy is insufficient. Other phenolic resins that can be used in combination with the phenolic resin of the present invention include monomers, oligomers, and polymers generally having two or more phenolic hydroxyl groups in one molecule, and their molecular weight and molecular structure are not particularly limited, For example, a phenol novolak resin, a cresol novolak resin, a dicyclopentadiene-modified phenol resin, a terpene-modified phenol resin, a triphenolmethane-type resin, and the like can be used, and these may be used alone or as a mixture. Particularly, a phenol novolak resin, a dicyclopentadiene-modified phenol resin, a terpene-modified phenol resin and the like are preferable.

[0007] The epoxy resin used in the present invention is a novolak structure epoxy resin containing a biphenyl derivative and / or a naphthalene derivative in the molecule. Specifically, the novolak structure epoxy resin containing a biphenyl derivative has the formula (1) Is obtained by glycidyl etherification of the phenol resin of the formula (1), and is represented by the formula (2). N in the expression (2) is 1 to 10
When n exceeds 10, the melt viscosity of the resin becomes too high and the fluidity decreases. In order to exhibit the flame-retardant property, it is desirable to mix the epoxy resin represented by the formula (2) in the total epoxy resin in an amount of 30% by weight or more, preferably 50% by weight or more. If it is less than 30% by weight, the flame retardancy is insufficient. A specific epoxy resin having a novolak structure containing a naphthalene derivative is obtained by subjecting a phenol resin of the formula (3) to glycidyl etherification and represented by the formula (4). In the formula (4), n is 1 to 10. When n exceeds 10, the melt viscosity of the resin becomes too high, and the fluidity decreases. In order to exhibit the flame retardant property, it is desirable to mix the epoxy resin represented by the formula (4) in the total epoxy resin in an amount of 30% by weight or more, preferably 50% by weight or more. If it is less than 30% by weight, the flame retardancy is insufficient. Other epoxy resins that can be used in combination with the epoxy resin of the present invention include monomers, oligomers, and polymers generally having two or more epoxy groups in one molecule, and their molecular weight and molecular structure are not particularly limited. , Biphenyl type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, phenol novolak type epoxy resin,
Cresol novolak epoxy resin, triphenolmethane epoxy resin, alkyl-modified triphenolmethane epoxy resin, epoxy resin containing triazine nucleus,
Examples thereof include dicyclopentadiene-modified phenol type epoxy resins, and these may be used alone or in combination.

As the curing accelerator used in the present invention, any one can be used as long as it promotes a curing reaction between an epoxy group and a phenolic hydroxyl group, and those generally used for a sealing material can be used. For example, 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, 2-methylimidazole, tetraphenylphosphonium / tetraphenylborate and the like can be mentioned, and these may be used alone or as a mixture. Absent.

As the inorganic filler used in the present invention, those generally used for a sealing material can be used. For example, fused silica powder, crystalline silica powder, talc, alumina, silicon nitride and the like can be mentioned, and these may be used alone or in combination. The amount of these components is preferably 60 to 95% by weight in the total resin composition in consideration of the balance between moldability and solder crack resistance, including the inorganic substance used as a core material of zinc molybdate described later. . If it is less than 60% by weight, the solder cracking resistance decreases with an increase in water absorption, and if it exceeds 95% by weight, problems such as wire sweep and pad shift are caused, which is not preferable.

[0010] The zinc molybdate used in the present invention acts as a flame retardant. Zinc molybdate is conventionally known to be effective as a smoke suppressant and flame retardant for vinyl chloride resins, but has not been applied to semiconductor encapsulants. Regarding the flame retardant mechanism of zinc molybdate, it is known that zinc molybdate promotes the carbonization of the cured resin component during combustion, which shuts off oxygen in the air, stops combustion, and stops flame retardation. Is considered to be achieved.

Although zinc molybdate may be used alone, it tends to absorb moisture easily, and if the amount is too large, the moisture absorption rate of the semiconductor device increases, and the moisture resistance reliability may decrease. Moldability decreases. Accordingly, inorganic materials, for example, transition metals, silica, alumina clay, talc, zinc oxide, calcium carbonate, aluminum nitride, silicon nitride, aluminum silicate, magnesium silicate, and other core materials coated with zinc molybdate are exemplified. But,
As the core material, fused spherical silica or talc is preferable in terms of ease of handling and cost. By coating the core material, only zinc molybdate on the surface acts as a flame retardant, and it is not necessary to mix a large amount of zinc molybdate, so that the increase in the moisture absorption rate can be suppressed and the moldability can be improved. it can.

The coating amount of zinc molybdate to fused spherical silica or talc is preferably 5 to 40% by weight. The average particle size of the fused spherical silica or talc coated with zinc molybdate is preferably 0.5 to 30 μm, and the maximum particle size is preferably 75 μm or less. The amount of zinc molybdate in the total resin composition is 0.05 to 5% by weight.
And more preferably 0.1 to 3% by weight.
If the content is less than 0.05% by weight, flame retardancy cannot be obtained. If the content exceeds 5% by weight, ionic impurities in the resin composition increase, and the moisture resistance reliability in a pressure cooker test or the like decreases, and the moldability also decreases. Is not preferred. The present invention obtained by coating fused spherical silica or talc with zinc molybdate can be obtained, for example, as follows. A slurry is prepared by mixing molybdenum oxide and fused spherical silica or talc in water, heated to 70 ° C., and a slurry of zinc oxide is slowly mixed with the slurry and stirred for about 1 hour. The solid is taken out by filtration, and after removing water at 110 ° C., it is pulverized. Thereafter, it is obtained by firing at 550 ° C. for 8 hours.

The zinc borate used in the present invention acts as a flame retardant, like zinc molybdate. Zinc borate is 4ZnO.B ₂ O ₃ because of its balance between flame retardancy and humidity resistance.
· H ₂ O and _{2ZnO · 3B 2 O 3 · 3.5H} 2 O are preferred, in particular, ₂ O ₃ · 4ZnO · B from consideration of the moldability
H ₂ O is more preferred. The zinc borate of the present invention can be easily obtained from the market. The content of zinc borate is preferably 1 to 20% by weight, more preferably 1 to 5% by weight, based on the whole resin composition. If it is less than 1% by weight, the flame retardancy is insufficient, and if it exceeds 20% by weight, the moisture resistance reliability and the moldability are undesirably reduced. The flame retarding mechanism of zinc molybdate is to promote the carbonization of the cured resin component, and the flame retarding mechanism of zinc borate is to release moisture and form a glassy coating. These are used alone as flame retardants, but when used in combination with resins that are unlikely to thermally decompose, such as phenolic resins and epoxy resins containing biphenyl derivatives and naphthalene derivatives, their respective flame retardant mechanisms are promoted and dramatically improved. High flame retardancy can be obtained.

The resin composition of the present invention comprises the components (A) to (E) as essential components, but if necessary, a silane coupling agent, a coloring agent such as carbon black, a natural wax, and a synthetic wax. And various additives such as low-stress additives such as silicone oil and rubber. Further, the resin composition of the present invention,
After sufficiently mixing the components (A) to (E) and other additives and the like using a mixer or the like, the mixture is further melt-kneaded with a hot roll or a kneader, cooled, and pulverized. Using the resin composition of the present invention, to encapsulate various electronic components such as semiconductors, and to manufacture a semiconductor device, transfer molding, compression molding, injection molding and other conventional molding methods such as curing molding Good.

[0015]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. The mixing ratio is by weight. In addition, the epoxy resin used in the Examples and Comparative Examples,
The abbreviations and structures of the phenolic resins are summarized below. Phenol resin (H-1): phenol resin of formula (1) (hydroxyl equivalent 199 g / eq, softening point 76.5 ° C.)

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Phenol resin (H-2): a phenol resin represented by the formula (5) (hydroxyl equivalent 210 g / eq, softening point 86 ° C.)

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Phenol resin (H-3): a phenol resin represented by the formula (6) (hydroxyl equivalent: 175 g / eq, softening point: 71 ° C.)

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Phenol resin (H-4): a phenol resin represented by the formula (7) (hydroxyl equivalent: 104 g / eq, softening point: 80 ° C.)

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Epoxy resin (E-1): an epoxy resin represented by the formula (2) (epoxy equivalent: 274 g / eq, softening point: 57.5 ° C.)

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Epoxy resin (E-2): an epoxy resin represented by the formula (8) (epoxy equivalent: 270 g / eq, softening point: 62 ° C.)

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Epoxy resin (E-3): an epoxy resin having the formula (9) as a main component (epoxy equivalent 190 g / eq,
(Melting point 105 ° C)

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Epoxy resin (E-4): an epoxy resin represented by the formula (10) (epoxy equivalent: 200 g / eq, softening point: 75 ° C.)

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Example 1 61 parts by weight of phenolic resin (H-1) 84 parts by weight of epoxy resin (E-1) 2 parts by weight of 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) Fused spherical silica 830 parts by weight Epoxysilane coupling agent 5 parts by weight Flame retardant A (coated with 2 parts by weight of zinc molybdate per 8 parts by weight of fused spherical silica having an average particle diameter of 18 μm and a specific surface area of 2.0 m ² / g) The average particle size of the flame retardant A is 24 μm and the maximum particle size is 74 μm.) 10 parts by weight of carbon black 3 parts by weight Carnauba wax 5 parts by weight are mixed at room temperature using a super mixer, and the mixture is mixed at 70 to 10
Roll kneading was performed at 0 ° C., followed by cooling and pulverization to obtain a resin composition. The obtained resin composition was evaluated by the following method. Table 1 shows the results.

Evaluation method Flame retardancy: 175 ° C. using a low pressure transfer molding machine
A test piece (127 mm × 1) was prepared at 70 kg / cm ² for 120 seconds.
(2.7 mm × 3.2 mm) and treated at 175 ° C. for 8 hours. Then, ΔF and Fmax were measured in accordance with the UL94 vertical method to determine the flame retardancy. High temperature storage characteristics: 17 using low pressure transfer molding machine
A 16 pDIP (chip size: 3.0 mm × 3.5 mm) was formed at 5 ° C., 70 kg / cm ² , 120 seconds, and 175
After 8 hours treatment at 185 ° C, 10 hours
00 hours), and the package in which the electric resistance between the wirings increased by 20% from the initial value was determined to be defective. The percentage defective in 15 packages was shown as a percentage. Units%. Moisture resistance reliability: The sealed test element was subjected to a pressure cooker test (125 ° C., 100% relative humidity) to measure the open failure of the circuit. The moisture resistance was defined as a failure occurrence time in a pressure cooker test.

Examples 2 to 10 and Comparative Examples 1 to 3 Resin compositions were prepared in the same manner as in Example 1 according to the formulations shown in Table 1, and evaluated in the same manner as in Example 1. Table 1 shows the results. The flame retardant B of Example 8 contained 7 parts by weight of talc,
It was coated with 3 parts by weight of zinc molybdate (average particle size: 2.1 μm, maximum particle size: 10 μm). Examples 9 and 1
Zinc borate of 0 is _{4ZnO · B 2 O 3 · H} 2 O.
In Comparative Example 1, a brominated bisphenol A type epoxy resin (epoxy equivalent: 365 g / eq) was used as a flame retardant.

[Table 1]

[0026]

[Table 2]

[0027]

According to the present invention, an epoxy resin composition for semiconductor encapsulation which does not contain halogen and antimony and has excellent moldability can be obtained.
Excellent in high temperature storage characteristics and humidity resistance reliability.

Claims (8)

[Claims] (A) a biphenyl derivative and / or
Or a phenol resin containing a novolak-type phenol resin containing a naphthalene derivative in an amount of 30 to 100% by weight based on the total phenol resin, (B) an epoxy resin, (C) a curing accelerator,
(D) an inorganic filler; and (E) at least one selected from fused spherical silica coated with zinc molybdate, talc coated with zinc molybdate, and zinc borate as essential components. Epoxy resin composition for semiconductor encapsulation. 2. A novolak-type epoxy resin containing (A) a phenolic resin and (B) a biphenyl derivative and / or a naphthalene derivative in a molecule in an amount of 30 to 1 in the total epoxy resin.
Epoxy resin containing 00% by weight, (C) a curing accelerator,
An epoxy resin composition for semiconductor encapsulation comprising, as an essential component, at least one selected from (D) an inorganic filler, (E) talc coated with zinc molybdate, and zinc borate. 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the ratio of the number of phenolic hydroxyl groups of the total phenolic resin to the number of epoxy groups of the total epoxy resin is more than 1 and 2 or less. 4. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the phenol resin having a novolak structure containing a biphenyl derivative in the molecule is represented by the formula (1). Embedded image (N is an average value and a positive number from 1 to 10) 5. The epoxy resin having a novolak structure containing a biphenyl derivative in the molecule is represented by the formula (2).
Or the epoxy resin composition for semiconductor encapsulation according to 3. Embedded image (N is an average value and a positive number from 1 to 10) 6. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the phenol resin having a novolak structure containing a naphthalene derivative in the molecule is represented by the formula (3). Embedded image (N is an average value and a positive number from 1 to 10) 7. The epoxy resin having a novolak structure containing a naphthalene derivative in the molecule is represented by the formula (4).
Or the epoxy resin composition for semiconductor encapsulation according to 3. Embedded image (N is an average value and a positive number from 1 to 10) 8. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.