JP2000017046A - Epoxy resin composition and resin-sealed type semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition excellent in resistance to reflow by compounding a specific epoxy resin and a specific curing agent and a specific curing accelerator and a specific inorganic filler. SOLUTION: The objective composition comprises an epoxy resin comprising at least 50 wt.% of an epoxy resin of formula I being solid at 25 deg.C, a curing agent comprising at least 50 wt.% of a phenol resin represented by formula II or III, a curing accelerator and an inorganic filler, where 2-20 wt.% of the total resin components, that is, the sum of the epoxy resin and the curing agent is a polyfunctional phenol resin or a polyfunctional epoxy resin represented by formula IV or V. In formula I, R1-10 are each H, an alkyl, a cycloalkyl, an aryl or a halogen; and A is CH2 or (CH3)2C. In formulae II and III, r is R1; (x) is 0-3; (y) is 0-5; (n) is 1-50; and A is a divalent group represented by formulae VI-X. In formulae IV-V, G is H or glycidyl; R is an alkyl, a cycloalkyl, an aryl or a halogen; (m) is 0-4; (p) is 0-2; (q) is 2-4; and (n) is 1-50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an epoxy resin composition and a resin-sealed semiconductor device using the same.

[0002]

2. Description of the Related Art At present, various semiconductor devices such as memories are sealed with a sealing resin mainly composed of an inexpensive epoxy resin with high productivity. Recently, in response to demands for high-density mounting of electronic components and automation of the assembly process,
Surface mounting has become mainstream as a semiconductor mounting method. In the surface mounting, high-temperature heat is applied to the entire package because processes such as solder immersion and infrared reflow are performed.

In the case where a conventional sealing resin is used, heat is generated at the time of surface mounting to cause separation between the resin and the bed due to a difference in thermal expansion between the resin and the lead frame material, and the resin is present inside the resin. Water evaporates rapidly, and cannot withstand the high internal pressure of water vapor inside the package, causing the resin to crack. Further, as the size of the chip increases and the thickness of the package decreases, the characteristics required for the sealing resin are becoming stricter than before.

Therefore, improvements in moisture resistance, crack resistance, and moldability of the sealing resin have been studied, and improvements have been made from various directions such as a resin matrix component such as an epoxy resin, a curing agent, and a catalyst, and a filler. .

For example, a biphenyl-type epoxy resin or a diphenylmethane-type epoxy resin is used as a matrix resin, and by filling the filler with a high amount, a sealing resin having reduced water absorption and thermal expansion coefficient and improved reflow resistance can be obtained. It is becoming widely used. But,
Even a sealing resin using a biphenyl-type epoxy resin or a diphenylmethane-type epoxy resin cannot be said to have sufficient reflow resistance.

Among them, the diphenylmethane type (bisphenol F type) or diphenylpropane type (bisphenol A type) epoxy resin has a lower viscosity than the biphenyl type epoxy resin, so that the filler can be filled at a high level, and the water absorption rate is reduced. It is a promising material with the characteristic of lowering it. However, the diphenylmethane (or propane) type epoxy resin has a drawback of low strength at high temperatures.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an epoxy resin composition excellent in reflow resistance and a highly reliable resin-encapsulated semiconductor device sealed with the epoxy resin composition. It is in.

[0008]

The epoxy resin composition of the present invention comprises (a) an epoxy resin, (b) a curing agent,
(C) a curing accelerator, and (d) an inorganic filler, wherein 50% by weight or more of the epoxy resin as the component (a) is:
An epoxy resin solid at 25 ° C. represented by the following formula (1):

[0009]

Embedded image (Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
R ⁸ , R ⁹ and R ¹⁰ are groups selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group and a halogen atom, and may be the same or different. A is methylene -CH ₂ - is (CH ₃₎ 2 divalent organic radical selected from the group consisting of ₂ C-- and isopropylidene. ) 50 w of the curing agent as the component (b)
t% or more is a phenol resin represented by the following formula (2) or (3),

[0010]

Embedded image (In the formula, R is a group selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, and a halogen atom, and may be the same or different.
Further, x is an integer of 0 to 3, y is an integer of 0 to 5, n is 1 to
It is an integer of 50. A is

[0011]

Embedded image And a divalent organic group selected from the group consisting of ) 2 of the total resin components obtained by summing the components (a) and (b)
-20 wt% is a polyfunctional phenol resin or a polyfunctional epoxy resin represented by the following formula (4) or (5).

[0012]

Embedded image (In the formula, G is a hydrogen atom or a glycidyl group. R is a group selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group, and a halogen atom, and may be the same or different. M is an integer of 0 to 4,
p is an integer of 0 to 2, q is an integer of 2 to 4, and n is an integer of 1 to 50. ).

A resin-encapsulated semiconductor device according to the present invention is a resin-encapsulated semiconductor device comprising a semiconductor element and a resin layer for encapsulating the semiconductor element, wherein the resin layer is formed by curing the epoxy resin composition. It is characterized by being a thing.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the present invention, 50% by weight or more of the epoxy resin as the component (a) is a so-called bisphenol F type (or A type) epoxy resin represented by the formula (1).
The epoxy resin of the formula (1) is a monomer having two glycidyl groups at both ends of a skeleton composed of diphenylmethane or diphenylpropane, but has a property of being solid at room temperature (25 ° C.). Substituents R ¹ to R ¹ in the formula (1)
R ¹⁰ is a group selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, and a halogen atom. Examples of the alkyl group include a methyl group, an ethyl group, and a propyl group. Examples of the cycloalkyl group include a cyclohexyl group and a cyclopentyl group. Examples of the aryl group include a phenyl group, a naphthyl group, and an anisyl group. Substituents R ^{1 to} R in the formula (1)
^The smaller the number of hydrogen atoms out of ^10, the more likely it is to form a solid at room temperature. Since the epoxy resin of the formula (1) is a monomer and has a low viscosity, it allows high filling of the filler.

The epoxy resin other than the one represented by the formula (1) among the epoxy resins as the component (a) includes 1
Any compound having two or more epoxy groups in the molecule can be used. Specific examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin,
Biphenyl-type epoxy resin, phenol novolak-type epoxy resin, cresol novolak-type epoxy resin, naphthol-type novolak-type epoxy resin, bisphenol-A novolak-type epoxy resin, tris obtained by epoxidizing a condensate of phenol or alkylphenol with hydroxybenzaldehyde Epoxidized (hydroxyphenyl) alkane, epoxidized tetra (hydroxyphenyl) alkane, 2,2 ′, 4
4'-tetraglycidoxybenzophenone, triglycidyl ether of paraaminophenol, polyallyl glycidyl ether, 1,3,5-triglycidyl ether benzene, 1,2,3-triglycidyl ether benzene, glycidyl ether of phenol aralkyl resin, etc. Is mentioned. One or more of these can be used.

In the present invention, 50% by weight or more of the curing agent as the component (b) is a so-called phenol aralkyl resin or naphthol aralkyl resin represented by the formula (2) or (3). The substituent R in the formula (2) or (3) is a hydrogen atom, an alkyl group, a cycloalkyl group,
It is a group selected from the group consisting of an aryl group and a halogen atom. As the alkyl group, a methyl group, an ethyl group,
And a propyl group. Examples of the cycloalkyl group include a cyclohexyl group and a cyclopentyl group. Examples of the aryl group include a phenyl group, a naphthyl group, and an anisyl group. If the phenol resin of the formula (2) or (3) is used, the water absorption of the sealing resin can be reduced.

Among the curing agents as the component (b), phenol resins other than those represented by the formula (2) or (3) include phenol novolak resins, cresol novolak resins, nonylphenol novolak resins, and bisphenol F type novolak resins. Novolak type phenolic resins such as bisphenol A type novolak resin, biphenyl type novolak resin, naphthol type novolak resin, hydroquinone, resorcinol, catechol, 1,2,3-trihydroxybenzene, 1,3,5-trihydroxybenzene and the like. No. One or more of these can be used.

Further, 2 to 2 of the total resin components (total of the epoxy resin (a) component and the curing agent (b) component)
20 wt% is a polyfunctional phenol resin or a polyfunctional epoxy resin represented by the formula (4) or (5). G in the formula (4) or (5) is a hydrogen atom (phenol resin) or a glycidyl group (epoxy resin). R in the formula (4) or (5) is a group selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group and a halogen atom. Examples of the alkyl group include a methyl group, an ethyl group, and a propyl group. Examples of the cycloalkyl group include a cyclohexyl group and a cyclopentyl group. Examples of the aryl group include a phenyl group, a naphthyl group, and an anisyl group.

By adding a polyfunctional phenol resin or a polyfunctional epoxy resin represented by the formula (4) or (5), it is possible to increase the heat strength of the sealing resin and improve the reflow resistance. When the content of the polyfunctional phenol resin or the polyfunctional epoxy resin is less than 2 wt%, the effect of improving the reflow resistance of the sealing resin cannot be obtained. On the other hand, if the content exceeds 20 wt%, the improvement in resin strength is saturated, but the elastic modulus increases according to the content, so that the cured resin becomes brittle, and the water absorption rate increases.
Again, the effect of improving the reflow resistance of the sealing resin cannot be obtained.

In the present invention, the mixing ratio of the epoxy resin to the phenol resin as a curing agent is determined by the ratio of the number of phenolic hydroxyl groups of the phenol resin to the number of epoxy groups of the epoxy resin (the number of phenolic hydroxyl groups / the number of epoxy groups). ) Is desirably adjusted to fall within the range of 0.5 to 1.5. If this value is less than 0.5, the curing reaction is unlikely to occur sufficiently, while if it exceeds 1.5, the properties of the cured resin, especially the moisture resistance, tend to deteriorate.

In the present invention, as the curing accelerator as the component (c), an amine-based, phosphorus-based, boron-based, phosphorus-boron-based curing accelerator or the like is used. In particular, when a phosphorus-based curing accelerator is used, the moisture resistance of the sealing resin is improved. The compounding ratio of the curing accelerator is 0.05% of the entire resin component.
It is preferably about 5% by weight.

In the present invention, silica powder or the like is used as the inorganic filler as the component (d). The amount of the inorganic filler is desirably 50 to 95% by weight of the entire resin composition. If it is less than 50 wt%, the mechanical strength is poor, and 95 w
If it exceeds t%, it is difficult to maintain sufficient fluidity, and workability such as kneading is inferior. From the viewpoint of preventing soft errors, uranium (U) and thorium (T
Preferably, the content of h) is 0.5 ppb or less.

In the epoxy resin composition of the present invention, one or more selected from the group consisting of silicone oil, silicone gel, silicone rubber, ABS resin and MBS resin may be used as additives. These components have the effect of reducing the elastic modulus of the cured resin and improving the reflow crack resistance.

The epoxy resin composition of the present invention contains, in addition to the above components, a releasing agent, a pigment, a filler surface treating agent,
A flame retardant aid or the like may be appropriately added. As a release agent,
Natural wax, synthetic wax, linear fatty acid and its metal salt, acid amide, ester, paraffin and the like can be mentioned. Examples of the pigment include carbon black and titanium dioxide. Examples of the filler surface treatment agent include a silane coupling agent. As flame retardant aids,
And antimony trioxide.

The method of adding the modifier may be, for example, a so-called integral blending method in which the modifier is added to the resin component or the filler, followed by stirring. And a method of stirring and mixing is desirable.

In the epoxy resin composition of the present invention, the above-mentioned components are melt-kneaded by a heating roll, a kneader or an extruder, mixed by a special mixer capable of pulverization, or by appropriately combining these methods. It can be easily manufactured.

The resin-encapsulated semiconductor device of the present invention can be easily manufactured by encapsulating a semiconductor chip with a resin using the above-described epoxy resin composition and a lead frame in a conventional manner. A general method of resin sealing is low pressure transfer molding, but methods such as injection molding, compression molding, and casting can also be used. Also,
It is desirable to perform after-curing at 175 ° C. or higher. The semiconductor element (chip) sealed in the present invention is not particularly limited.

[0028]

The present invention will be described in more detail with reference to the following examples. Examples 1 to 8 and Comparative Examples 1 to 5 The following components were used as raw materials.

Epoxy resin A: diphenylmethane type epoxy resin. (1) In the formula, R ¹ , R ³ , R ⁶ , and R ⁸ are methyl groups, other substituents R are hydrogen atoms, and A is a methylene group. (Nippon Steel Chemical, ESLV-80XY, epoxy equivalent 196).

Epoxy resin B: diphenylmethane type epoxy resin. (1) In the formula, R ¹ , R ² , R ³ , R ⁵ , R
⁶ , R ⁸ is a methyl group, the other substituent R is a hydrogen atom, A
Is a methylene group. (Nippon Steel Chemical, GK-800
1, epoxy equivalent 205).

Epoxy resin C: polyfunctional epoxy resin.
(Sumitomo Chemical's ESX-221, epoxy equivalent 21
6). Curing agent A: phenol aralkyl resin. (Manufactured by Mitsui Toatsu Chemicals, XL-225-4L, phenol equivalent 170).

Curing agent B: naphthol type phenol aralkyl resin. (Nippon Steel Chemical, SN-180, phenol equivalent 191). Curing agent C: polyfunctional phenol resin. (Made from oily shell epoxy, phenol equivalent 98). Curing agent D: polyfunctional phenol resin. What is represented by the following formula.

[0033]

Embedded image

Curing accelerator: triphenylphosphine Coupling agent: γ-glycidoxypropyltrimethoxysilane Release agent: ester wax Pigment: carbon black Inorganic filler: silica powder These components are shown in Tables 1 and 2. The components were blended at the indicated ratios (the numerical values in the table indicate parts by weight), and an epoxy resin composition was prepared as follows. First, the filler is surface-treated with a silane coupling agent in a Henschel mixer, then the other components are mixed, kneaded with a heating roll at 60 to 130 ° C., cooled, and then pulverized to obtain an epoxy resin composition. Obtained.

Next, Examples 1 to 8 and Comparative Examples 1 to 5
The following evaluation test was performed using the epoxy resin composition of (1). [1] Flexural strength and flexural modulus Using each resin composition, a test piece having a size of 10 mm × 4 mm × 80 mm was prepared by transfer molding at 180 ° C. for 1 minute, and after-cured at 175 ° C. for 8 hours. did. A three-point bending test was performed to measure bending strength and flexural modulus. The measurement was performed under the conditions of a distance between supporting points of 64 mm and a crosshead speed of 2 mm / min. Also, 24
The test at 0 ° C. was performed after the test piece was left at 240 ° C. for 4 minutes.

[2] Water Absorption Percentage of 30 mm at 180 ° C. for 1 minute using each resin composition
A test piece of × 30 mm × 1 mm was prepared, and the water absorption was measured at 85 ° C. and a relative humidity of 85%.

[3] Reflow crack resistance Using each epoxy resin composition, a test device (17 m
m × 17 mm chip) with a sealing resin size of 40 mm
× 40mm × 3mm, sealed at 175 ° C
After hours cure. Next, add this package to 85
C., after leaving it in an atmosphere of 85% relative humidity for 168 hours to perform a moisture absorption process, and an infrared reflow process at 240 ° C.
The incidence of cracks was examined.

[4] Humidity Reliability The same package as that used in the reflow crack resistance test was used as a test package. Package [3]
After the moisture absorption treatment and the infrared reflow treatment under the same conditions as those described above, the sample was left in a saturated steam atmosphere at 127 ° C., and the occurrence rate of defects (leak defect, open defect) was examined.

[5] Thermal Shock Resistance A semiconductor chip (15 mm × 15 mm) for a thermal shock resistance test was sealed with each epoxy resin composition, and after-cured at 175 ° C. for 8 hours. After the package is subjected to moisture absorption and infrared reflow treatment under the same conditions as in [3],-
65 ° C (30 minutes) → Room temperature (5 minutes) → 150 ° C (30 minutes)
→ 50 cycles of cooling and heating with one cycle at room temperature (5 minutes)
Up to 400 cycles were repeated, and the failure occurrence rate was examined by checking the operation characteristics of the device.

The results are shown in Tables 3 and 4. The evaluations in Tables 3 and 4 are as follows. Comparative Examples 1 and 2, which do not contain a polyfunctional phenol resin or a polyfunctional epoxy resin, have low strength at heat and poor reflow resistance. Comparative Examples 3 to 5 in which the addition amount of the polyfunctional phenol resin or the polyfunctional epoxy resin exceeds 20% by weight of all the resin components have a large water absorption. Further, Comparative Examples 3 to 5 have the same strength at the time of heating as compared with Example 4, but are more brittle than Example 4 because the elastic modulus at the time of heating is large. Therefore, Comparative Examples 3 to 5
Also have poor reflow resistance. In contrast to these comparative examples, Examples 1 to 8 all have a good balance of strength at heat, elastic modulus at heat, and water absorption, and show excellent reflow resistance.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

[0045]

As described in detail above, according to the present invention, it is possible to provide an epoxy resin composition excellent in reflow resistance due to low water absorption and high strength at hot time. By sealing a semiconductor element with this epoxy resin composition, a highly reliable resin-sealed semiconductor device can be provided.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshinori Yoshioka 1st Toshiba R & D Center, Komukai-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Kazutaka Matsumoto Komukai, Koyuki-ku, Kawasaki-shi, Kanagawa No. 1 Toshiba-cho, Toshiba R & D Center (72) Inventor Tetsuo Okuyama No. 1, Komukai Toshiba-cho, Koyuki-ku, Kawasaki, Kanagawa Pref. Toshiba R & D Center F-term (reference) GQ05 4J036 AA01 AA02 AD08 FB07 FB08 JA07

Claims (2)

[Claims] (1) an epoxy resin, (b) a curing agent,
In the epoxy resin composition containing (c) a curing accelerator and (d) an inorganic filler, 50% by weight or more of the epoxy resin as the component (a) is 25 ° C. represented by the following formula (1). And a solid epoxy resin, (Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
R ⁸ , R ⁹ and R ¹⁰ are groups selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group and a halogen atom, and A represents —CH ₂ — and — (C
H ₃ ) _{2 A} bivalent organic group selected from the group consisting of C—. ) 50% by weight or more of the curing agent as the component (b) is a phenol resin represented by the following formula (2) or (3); (Wherein, R is a group selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group and a halogen atom, x is an integer of 0 to 3, y is an integer of 0 to 5, and n is A is an integer of 1 to 50, and A is And a divalent organic group selected from the group consisting of ) 2 of the total resin components obtained by summing the components (a) and (b)
Up to 20% by weight is a polyfunctional phenol resin or a polyfunctional epoxy resin represented by the following formula (4) or (5). (Wherein, G is a hydrogen atom or a glycidyl group, R is a group selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group, and a halogen atom;
An integer of 4, p is an integer of 0 to 2, q is an integer of 2 to 4, and n is an integer of 1 to 50. A) an epoxy resin composition characterized in that: 2. A resin-encapsulated semiconductor device comprising a semiconductor element and a resin layer for encapsulating the semiconductor element, wherein the resin layer is a cured product of the epoxy resin composition according to claim 1. A resin-sealed semiconductor device characterized by the above-mentioned.