JP3385953B2 - Epoxy resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention provides a cured product which has few voids inside and on the surface, has excellent permeability to semiconductor devices, and has good adhesiveness to various substrates. The present invention relates to an epoxy resin composition that can be suitably used for sealing semiconductor devices.

[0002]

2. Description of the Related Art Epoxy resin compositions are used not only in electrical and electronic fields but also in various fields because of their excellent cured physical properties. At present, it is used under various flow characteristics such as extremely low viscosity and high thixotropic property.

Therefore, in the epoxy resin composition, air bubbles caused by entrainment during potting or dropping cannot be removed to the outside during the curing process, and remain as voids inside or on the surface of the cured product, or during transfer molding. It has been pointed out that there is a problem with air bubbles, such that the air entrained when flowing into the cavity from the gate is not discharged but remains as an internal void and becomes a defective product.

On the other hand, recently, potting and COB methods have been widely used as a sealing method for semiconductor devices. In this method, since the resin must be poured into a very narrow space between the gold wires extending from the semiconductor element, the conventional liquid epoxy resin composition has a problem in filling property.

In this case, in order to reduce voids, Florard FC-170C, FC-430, FC-431
Fluorine-based surfactants such as Sumitomo 3M Ltd. and K
It is well known to use a silicone-based surfactant such as F351, KF945, KF618 (manufactured by Shin-Etsu Chemical Co., Ltd.).

However, at present, even if these surfactants are used, the effect of preventing the occurrence of voids is not yet satisfactory. Further, the potting and COB methods have not been sufficiently studied, and only the measures to reduce the viscosity of the resin and the thixotropy of the resin have been taken in order to improve the filling property.

The present invention has been made in order to solve the above-mentioned problems, and it is a cured product having few internal and surface voids, excellent permeability to semiconductor devices, and good adhesiveness to various substrates. It aims at providing the epoxy resin composition which gives.

[0008]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of extensive studies by the present inventor to achieve the above object, an epoxy resin composition containing an epoxy resin, a curing agent and an inorganic filler, By blending an appropriate amount of a compound containing a fluorine atom and a silicon atom represented by the following structural formula (1), the permeability to a semiconductor device becomes very good, and sufficient defoaming and defoaming effects are exhibited. At the same time, the surface tension is lowered, and therefore, the generation of voids inside and on the surface of the cured product can be satisfactorily reduced, and the adhesiveness to various substrates is also good. Therefore, such an epoxy resin composition is The present invention has been completed by finding that it can be suitably used for sealing semiconductor devices by potting or COB method.

[0009]

[Chemical 2] (However, in the formula, R and R ¹ are each independently an unsubstituted or substituted monovalent hydrocarbon group, k is an integer of 10 to 80, and m is 1
Is an integer of 20 and n is an integer of 1-10. )

Therefore, the present invention provides (A) an epoxy resin,
(B) Hardener, (C) Inorganic filler, (D) Fluorine- and silicon atom-containing compound represented by the above structural formula (1) is 5 × with respect to 100 parts by weight of the total amount of the epoxy resin and the hardener.
Provided is an epoxy resin composition characterized by containing 10 ^-6 to 1 × 10 ^-1 part by weight.

The present invention will be described in more detail below. The epoxy resin composition of the present invention contains an epoxy resin, a curing agent, an inorganic filler and the like.

Here, as the epoxy resin used in the present invention, any epoxy resin having two or more epoxy groups in one molecule can be used, and in particular, bisphenol A type epoxy resin and bisphenol. Bisphenol type epoxy resin such as F type epoxy resin, phenol novolak type epoxy resin, novolak type epoxy resin such as cresol novolak type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, triphenol alkane type epoxy resin, phenol aralkyl Type epoxy resin, cyclopentadiene type epoxy resin and the like.

When the liquid epoxy resin composition is used,
Among the above, bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin are typically used.

Next, as the curing agent, when the composition is used for transfer molding, any phenolic resin having two or more phenolic hydroxyl groups in one molecule can be used. Novolak type phenolic resins such as phenol novolac resin and cresol novolac resin, phenol aralkyl resin, triphenol alkane type resin, naphthalene type phenol resin,
Cyclopentadiene type phenol resin is preferably used. The amount of the curing agent used is preferably such that the phenolic hydroxyl group in the phenol resin is 0.5 to 2 mol, particularly 0.8 to 1.3 mol, relative to 1 mol of the epoxy group in the epoxy resin. .

In this case, as the curing accelerator, for example, a phosphorus-based compound, an imidazole derivative, a cycloamidine-based derivative or the like can be blended, and the addition amount of these curing accelerators is 100% by weight of the total amount of the epoxy resin and the curing agent. It is preferably 0.05 to 10 parts by weight with respect to parts.

In the case of a liquid epoxy resin composition, as the curing agent, acid anhydrides such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride and methylhymic acid anhydride are preferable. used. When such an acid anhydride is used as a curing agent, 0.3 to 0.7 mol, particularly 0.4 to 0.6 mol of an acid anhydride is added to 1 mol of the epoxy group in the epoxy resin. It is desirable that the blending amount is 0.
If it is less than 3 mol, curability may be insufficient, and
If it exceeds 7 mol, unreacted acid anhydride may remain and the glass transition temperature may decrease.

Further, as a curing accelerator when an acid anhydride is used as a curing agent, 2-methylimidazole, 2-
Ethyl-4-methylimidazole, 1-cyanoethyl-
An imidazole derivative such as 2-methylimidazole or 2-phenyl-4,5-dihydroxymethylimidazole can be added.

Although these imidazole derivatives can be used both as a curing accelerator for an acid anhydride type curing agent and as a curing agent for an epoxy resin, when used as a curing accelerator, the epoxy resin and the curing agent are used. The total amount of 100
0.01 to 10 parts by weight, especially 0.5 to 5 parts by weight
It is preferable to add it in the range of parts by weight. If the addition amount is less than 0.01 parts by weight, the curability may decrease, and if it exceeds 10 parts by weight, the curability may be excellent, but the storage stability may decrease.

In addition to the above, carboxylic acid hydrazides such as dicyandiamide, adipic acid hydrazide and isophthalic acid hydrazide can be used as the curing agent.

Various conventionally known inorganic fillers can be added to the present invention for the purpose of reducing the expansion coefficient. As the inorganic filler, for example, fused silica, crystalline silica, alumina, boron nitride, aluminum nitride, silicon nitride, magnesia, magnesium silicate and the like are used. When the semiconductor device is an element that generates a large amount of heat, it is desirable to use alumina, boron nitride, aluminum nitride, silicon nitride, etc., which have the highest thermal conductivity and small expansion coefficient, among these. May be used by blending with fused silica or the like.

The particle size distribution of the inorganic filler has an average particle size of 2
It is desirable that the maximum particle size is ˜30 μm and the maximum particle size is 74 μm or less. If the average particle size is less than 2 μm, the viscosity becomes high, and it may not be possible to fill a large amount, and if it exceeds 30 μm, the coarse particle size increases, and there is a possibility that the gate will be clogged or the fine needle of the dispenser will be blocked.

The shape of the filler is not particularly limited,
The flaky, dendritic, spherical fillers can be used alone or in combination. Further, ultrafine silica such as Aerosil may be added to impart thixotropy.

It is preferable to use those fillers which have been surface-treated with a coupling agent such as a silane coupling agent or a titanium coupling agent in advance.

When the inorganic filler is used, it is 100 to 10 with respect to 100 parts by weight of the total amount of the epoxy resin and the curing agent.
00 parts by weight is preferred.

In the present invention, a fluorine and silicon atom-containing compound (that is, a perfluoroalkylethyl group-containing compound) represented by the following structural formula (1) is added to an epoxy resin composition containing the above epoxy resin, a curing agent and an inorganic filler. Diorganopolysiloxane).

[0026]

[Chemical 3] (However, in the formula, R and R ¹ are each independently an unsubstituted or substituted monovalent hydrocarbon group, k is an integer of 10 to 80, and m is 1
Is an integer of 20 and n is an integer of 1-10. )

R and R ¹ in the above formula (1) are each independently the same or different, unsubstituted or substituted monovalent hydrocarbon group, preferably an unsubstituted or substituted C 1-10 group. A monovalent hydrocarbon group, more preferably an unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms excluding an aliphatic unsaturated group, and specifically, a methyl group, an ethyl group, a propyl group, Alkyl groups such as isopropyl group, butyl group, isobutyl group, tert-butyl group, hexyl group, cyclohexyl group and octyl group, aryl groups such as phenyl group, tolyl group, xylyl group and naphthyl group, vinyl group, allyl group, propenyl group Groups, alkenyl groups such as isopropenyl group, butenyl group, isobutenyl group and hexenyl group, aralkyl groups such as benzyl group and phenylethyl group, and 3,3,3-trifluoropropyl group Include a halogen-substituted alkyl group, particularly a methyl group, a propyl group, a phenyl group are preferable. A plurality of R and R ¹ may be the same or different groups independently of each other, but 50 mol% or more of R,
Particularly, those having 70 to 100 mol% of methyl groups are preferable. k is an integer of 10 to 80, m is 1 to 20, preferably 2 to 12, more preferably 2 to 8, and n is 1 to 1.
It is an integer of 0, preferably 3 to 8, and more preferably 6 to 8.

Such a compound of the formula (1) is a linear diorganopolysiloxane in which both ends of the molecular chain are blocked with trimethylsiloxy groups and the number of silicon atoms (or the degree of polymerization) in the molecule is 122 or less. In the siloxane chain, 1 to 20 perfluoroalkylethyl group-containing siloxane units are randomly present, which is usually liquid at room temperature (25 ° C.) (oil-like). Can be exemplified by the following perfluoroalkylethyl group-containing organopolysiloxane compounds.

[0029]

[Chemical 4] (However, k and m in the formula have the same meanings as described above.)

[0030]

[Chemical 5] (However, in the formula, R and R ¹ have the same meanings as described above.)

The compound of the above formula (1) has a surface tension of 10 to 30 dyne / cm, especially 16 to 2 at room temperature (25 ° C.).
When the surface tension is less than 10 dyne / cm, a satisfactory effect may not be obtained, and when the surface tension is more than 30 dyne / cm, the defoaming property may be poor and the foaming may be easy. There is.

The amount of the compound of the above formula (1) used is 5 × 1 based on 100 parts by weight of the total amount of the epoxy resin and the curing agent.
0 ^-6 to 1 x 10 ^-1 part by weight, preferably 5 x 10 ^{-5 to} 5 x
^10-3 parts by weight and, 5 × 10 ^-6 sufficient defoaming is less than parts by weight, no foam breaking effect, also the permeability to narrow gaps from the inability to lower the surface tension of the composition If it exceeds 1 × 10 ⁻¹ parts by weight, on the contrary, the foamability will appear and the adhesiveness will also deteriorate.

In addition to the above components, the epoxy resin composition of the present invention may be blended with silicone rubber, silicone oil, silicone modified resin, liquid polybutadiene rubber or the like for the purpose of reducing stress.

Further, the composition of the present invention comprises, for the purpose of decreasing the viscosity, any of conventionally known n-butyl glycidyl ether, phenyl glycidyl ether, styrene oxide, t-butyl phenyl glycidyl ether and dicyclopentadiene diepoxide. Such diluents can be added.

Further, in addition to the above-mentioned silane coupling agent and titanium-based coupling agent, a coupling agent such as an aluminum-based coupling agent, a coloring agent such as carbon black, and a surfactant other than the compound of the above formula (1). As a nonionic surfactant, a fluorosurfactant, a wetting improver such as silicone oil, a defoaming agent and the like can be added as the case may be. The amount of these additives added is
A usual amount can be used within a range that does not impair the effects of the present invention.

The epoxy resin composition of the present invention is prepared by, for example, stirring or dissolving, mixing and dispersing the epoxy resin and the curing agent at the same time or separately while optionally applying heat treatment, and adding the inorganic filler, the above formula ( It can be obtained by adding the compound of 1) and other additives, mixing, stirring and dispersing. The device for mixing, stirring, dispersing, etc. is not particularly limited, but a liqui machine equipped with a stirring and heating device,
A triple roll, a ball mill, a planetary mixer or the like can be used.

When an epoxy resin for transfer molding is used, the epoxy resin and the curing agent, the inorganic filler,
It can be produced by uniformly mixing the compound of the above formula (1) and the like with a high-speed stirring device and then kneading with a hot two-roll or continuous kneading device. Further, these devices may be appropriately combined and used.

The epoxy resin composition of the present invention can be easily cured by heating, and the curing conditions are not particularly limited, but usually 100 to 190 ° C. and 0.5 to 10 hours are desirable.

[0039]

The epoxy resin composition of the present invention is excellent in filling in the gap between the semiconductor device and the substrate, has few voids inside and on the surface, and has good adhesiveness to various substrates. It gives a cured product and can be suitably used for potting, sealing a semiconductor device by a COB method, and the like.

[0040]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the formulas below, Me represents a methyl group and Ph represents a phenyl group, and all parts in each example are parts by weight.

Examples 1 to 8 and Comparative Examples 1 to 4 Tables 1 and 2
As shown in Figure 2, bisphenol A as liquid epoxy resin
Type epoxy resin (RE310S: manufactured by Nippon Kayaku Co., Ltd.), acid anhydride (Ricacid MH700: manufactured by Shin Nippon Rika Co., Ltd.) as a curing agent, fused silica (SE15 (average particle size 15 μm):
Tokuyama Soda Co., Ltd.), silane coupling agent (γ-glycidoxypropyltrimethoxysilane KBM403: Shin-Etsu Chemical Co., Ltd.), curing catalyst (UCAT5002: Asahi Kasei Corp.), containing fluorine and silicon atoms represented by the following structural formula Compounds (perfluoroalkylethyl group-containing silicone oils (i) to (iv)) were blended to produce an epoxy resin composition.

[0042]

[Chemical 6]

[0043]

[Chemical 7]

Various properties of the obtained epoxy resin composition were measured by the following methods. The results are also shown in Tables 1 and 2. Methods for measuring various properties Viscosity: Measured at room temperature using a Brookfield viscometer. Penetration: A glass plate is placed on an alumina substrate with a gap of 70 μm, and the epoxy resin composition heated to 60 ° C. is dropped on the edge of the glass plate. The permeation rate during permeation was determined. Surface void: 5 degassed completely in a 1 liter flask
After adding 00 g of the resin composition and rotating the stir bar at a speed of 120 rotations / minute for 10 minutes to allow air to be trapped inside, the mixture is poured into an aluminum Petri dish having a diameter of 50 mm and a depth of 15 mm, and the temperature is 100 ° C. for 1 hour. The number of surface voids was counted after curing at 150 ° C. for 2 hours. Bubble generation amount: Only 5 g of the resin component of the completely defoamed resin composition shown in Tables 1 and 2 was placed in a 300 cc beaker, the pressure was reduced to 750 mmHg, and the bubble generation amount at that time was measured.

From the results shown in Tables 1 and 2, it was confirmed that the epoxy resin composition of the present invention had excellent penetrability and had very few surface voids in the cured product.

[0046]

[Table 1]

[0047]

[Table 2]

[Example 9 and Comparative Example 5] Epoxycresol novolac resin (EOCN1020: manufactured by Nippon Kayaku Co., Ltd.)
167.9 parts, phenol novolac resin (TD209
3: Dainippon Ink and Co., Ltd.) 90.6 parts, brominated epoxy resin (BREN-S: Nippon Kayaku Co., Ltd.) 36.6 parts, fused silica (RD8 (average particle size 8 μm): Tatsumori Co., Ltd.) 67
8.9 parts, carbon black 3 parts, carnauba wax 3
Part, silane coupling agent (γ-glycidoxypropyltrimethoxysilane KBM403: manufactured by Shin-Etsu Chemical Co., Ltd.)
3 parts, a curing catalyst (triphenylphosphine TPP: manufactured by Kitako Chemical Co., Ltd.) 2.4 parts, and 0.29 parts of a perfluoroalkylethyl group-containing silicone oil of the above formula (i) as a compound containing fluorine and a silicon atom, An epoxy resin composition for transfer molding (Example 9) was obtained by kneading with a continuous kneading device after mixing with a high-speed mixing device.

Further, an epoxy resin composition for transfer molding (Comparative Example 5) was obtained by kneading in the same manner as in Example 9 except that fluorine and silicon atom-containing compounds were not used.

After curing the epoxy resin compositions of Example 9 and Comparative Example 5 under the conditions of a temperature of 175 ° C. and a molding pressure of 70 kg / cm ² for 2 minutes, the spiral flow and the internal void formation were examined as follows. It evaluated by the method shown in. The results are shown in Table 3. Spiral flow: Measured using a mold conforming to the EMMI standard. Internal void: 1 equipped with an 8 mm square silicone chip
After the 00-pin QFP package was sealed under the above conditions, the number of internal voids in the package was measured with a soft X-ray device. The number of voids is the number in 10 packages.

From the results shown in Table 3, it was found that the epoxy resin composition of the present invention generated few internal voids.

[0052]

[Table 3]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C08L 83:08) (56) Reference JP-A-2-173155 (JP, A) JP-A-62-119225 (JP, A) JP-A-59-67688 (JP, A) JP-A-58-69244 (JP, A) JP-A-57-3821 (JP, A) JP-A-63-142024 (JP, A) JP-A-8-253659 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 63/00-63/10 C08L 83/08 H01L 23/29

Claims (2)

(57) [Claims] 1. An epoxy resin (A), a curing agent (B),
(C) Inorganic filler, (D) 5 × 10 ⁻⁶ to 1 × 1 of the fluorine- and silicon-atom-containing compound represented by the following structural formula (1) based on 100 parts by weight of the total amount of the epoxy resin and the curing agent.
An epoxy resin composition comprising 0 ^-1 part by weight. [Chemical 1] (However, in the formula, R and R ¹ are each independently an unsubstituted or substituted monovalent hydrocarbon group, k is an integer of 10 to 80, and m is 1
Is an integer of 20 and n is an integer of 1-10. ) 2. The epoxy resin composition according to claim 1, wherein the compound of the structural formula (1) has a surface tension of 10 to 30 dyne / cm at room temperature.