JP3033445B2 - Inorganic filler for resin and epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a resin composition which has a low viscosity in a molten state at room temperature or high temperature, has a good fluidity, and has a good flowability even when it is incorporated in a large amount into an epoxy resin or the like for the purpose of reducing hygroscopicity. The present invention relates to an inorganic filler for a resin that hardly gives aggregates in the resin and an epoxy resin composition using the filler.

[0002]

2. Description of the Related Art
In the semiconductor industry, resin-sealed type diodes, transistors, ICs, LSIs, and ultra-LSIs are the mainstream, and epoxy resin is generally more moldable and adhesive than other thermosetting resins. Because of their excellent electrical properties, mechanical properties, moisture resistance, etc., semiconductor devices are often sealed with epoxy resin compositions.

In recent years, the degree of integration of these semiconductor devices has been increasing, and the chip size has been increasing accordingly. On the other hand, package external dimensions have been reduced in thickness in response to demands for smaller and lighter electronic devices. Further, in the method of attaching a semiconductor component to a circuit board, the surface mounting of the semiconductor component has been widely performed due to the high density of components on the substrate and the thinning of the substrate.

However, when a semiconductor device is surface-mounted, it is common to immerse the entire semiconductor device in a solder bath or to pass the semiconductor device through a zone where the solder melts. Cracks occur, or separation occurs at the interface between the lead frame or chip and the sealing resin. Such cracks and peeling become more remarkable when the sealing resin layer of the semiconductor device absorbs moisture before the thermal shock at the time of surface mounting. Therefore, the reliability of the semiconductor device sealed with the epoxy resin after mounting may be greatly impaired.

[0005] Under such circumstances, a low-hygroscopic sealing resin has been demanded in order to reduce the moisture absorption of the sealing resin layer and prevent cracks and peeling during surface mounting. It is known that it is effective to mix a large amount of an inorganic filler as one of the methods for obtaining a low-hygroscopic sealing resin.

However, when a large amount of an inorganic filler is added to the encapsulating resin composition, there is a problem that the melt viscosity is increased and the flow characteristics are deteriorated. The melt viscosity of the resin composition must be as low as possible.

In this case, it is known to use a filler having a large particle size and a filler having a small particle size in combination in order to lower the melt viscosity, and to control the interface between the resin and the inorganic filler. It is known that a method of surface-treating an inorganic filler with a silane coupling agent is known. However, even with these methods, a decrease in viscosity in a molten state at a room temperature to a high temperature is insufficient, and a large amount of aggregates of the inorganic filler is generated. And the mechanical strength of the cured product is reduced.

The present invention has been made in view of the above circumstances, and has a low viscosity in a molten state from room temperature to a high temperature even when it is blended in a large amount into an epoxy resin or the like for the purpose of reducing the hygroscopicity, and has good flow characteristics. Further, an object of the present invention is to provide an inorganic filler for a resin, which hardly gives an aggregate of the inorganic filler when mixed with a resin, and an epoxy resin composition using the filler.

[0009]

The inventors of the present invention have made intensive studies to achieve the above object, and have found that 100 parts by weight of an inorganic filler having an average particle size of 5 to 40 μm is substituted with a silane containing an alkoxy group and a glycidoxy group. Or 100 parts by weight of a surface-treated filler treated with a partial hydrolyzate thereof, and inorganic fillers 1 to 4 which have not been surface-treated and have an average particle size of 4 μm or less.
It has been found that a filler obtained by mixing 0 parts by weight is effective.

That is, it has been known to use fillers having different average particle sizes in combination, and it has also been known to treat the surface of an inorganic filler with an alkoxy group-containing silane or a partial hydrolyzate thereof. The present inventors have attempted to use a filler having a different average particle size by combining these, and to treat each with an alkoxy group-containing silane or a partial hydrolyzate thereof.
Fillers are often agglomerated, so the cured product has poor mechanical strength, whereas when fillers with different average particle sizes are used in combination, only the larger particle size has an alkoxy group-containing silane or a part thereof. By treating with a hydrolyzate and mixing them without surface treatment of the smaller particle size with an alkoxy group-containing silane or its partial hydrolyzate, surprisingly less agglomerated when blended with resin, In addition, the present inventors have found that the viscosity at the time of melting from ordinary temperature to high temperature is low and the fluidity is good, and the present invention has been accomplished.

Accordingly, the present invention relates to (A) a surface-treated filler 10 obtained by treating 100 parts by weight of an inorganic filler having an average particle size of 5 to 40 μm with a silane containing an alkoxy group and a glycidoxy group or a partial hydrolyzate thereof.
0 parts by weight, and (B) 1 to 40 parts by weight of an inorganic filler having an average particle diameter of 4 μm or less, which has not been surface-treated, and an inorganic filler for a resin, and an epoxy resin and a curing agent. An epoxy resin composition comprising: an inorganic filler; and an inorganic filler, wherein the inorganic filler for a resin is used as the inorganic filler.

Hereinafter, the present invention will be described in more detail. The inorganic filler for a resin of the present invention comprises, as described above, (A) an inorganic filler having a large average particle diameter treated with an alkoxy group-containing silane or a partial hydrolyzate thereof. And a mixture of (B) an inorganic filler having a small average particle size, which is not surface-treated with an alkoxy group-containing silane or a partial hydrolyzate thereof.

In the present invention, the average particle size of the inorganic filler (A) is 5 to 40 μm, preferably 7 to 30 μm.
m. When the average particle diameter is smaller than 5 μm, the effect of using the inorganic filler having the smaller average particle diameter of the component (B) is not exhibited, and when the average particle diameter is larger than 40 μm, the fluidity at the time of melting deteriorates. As the kind of the inorganic filler that can be used, a conventionally known inorganic filler can be used, and examples thereof include crushed or spherical fused silica, crystalline silica, alumina, silicon nitride, and aluminum nitride. it can. Also, average particle size, material,
Two or more inorganic fillers having different shapes may be used in combination.To achieve both low expansion of the cured product and moldability, it is necessary to use a spherical product and a crushed product together, or use only a spherical product. Recommended.

As the alkoxy group and glycidoxy group-containing silane for treating such an inorganic filler, conventionally known silanes can be used. For example, 3-glycidoxypropyltrimethoxysilane, 1,3-bis (γ -Glycidoxypropyl) -1,1,3,3-tetramethoxy-
1,3-disiloxane and the like can be mentioned, and these partial hydrolysates can also be used.

The amount of the alkoxy group-containing silane or its partial hydrolyzate is preferably 0.1 to 1 part, more preferably 0.1 to 0 part, per 100 parts (parts by weight, hereinafter the same) of the inorganic filler. .6 parts. When the amount is less than 0.1 part, when mixed with the resin composition, the interface between the resin and the inorganic filler may not be sufficiently controlled, and when the amount is more than 1 part, aggregates may be formed. It may be easier.

The method of preparing the surface-treated filler of the component (A) is not particularly limited, but the alkoxy group-containing silane or the alkoxy group-containing silane or inorganic filler placed in a known mixer such as a Henschel mixer is sprayed or sprayed. The partial hydrolyzate can be sprinkled and then obtained by mixing with an inorganic filler. As it is, it may be mixed with the inorganic filler of the component (B), but after leaving it at room temperature for several days or heat-treating it,
It is preferred to remove agglomerates through a ~ 200 mesh sieve.

On the other hand, as the inorganic filler having an average particle diameter of the component (B) of 4 μm or less, preferably 0.2 to 3 μm, conventionally known inorganic fillers can be used, for example, crushed or spherical fused silica, Besides crystalline silica, alumina, silicon nitride, aluminum nitride and the like can be mentioned.
Further, two or more inorganic fillers having different average particle diameters, materials and shapes may be used in combination.

The amount of the inorganic filler (B) to be used should be in the range of 1 to 40 parts, preferably 3 to 30 parts, per 100 parts of the surface-treated inorganic filler (A). . If the amount is less than 1 part, the viscosity in the molten state at room temperature or high temperature when mixed with the resin cannot be sufficiently reduced, while when it exceeds 40 parts, it is economically disadvantageous or aggregation is likely to occur. Become.

The mixing of the fillers of the components (A) and (B) can be performed using a conventionally known mixing apparatus. Specific examples include a mixer such as a Henschel mixer, a vertical mixer, a ball mill, and a concrete mixer. After the mixing, it is preferable to remove aggregates using a 100 to 200 mesh sieve.

When a large amount of the inorganic filler for resin of the present invention is blended with a resin, the viscosity at the time of melting from room temperature to high temperature is low, good fluidity is maintained, and aggregates when blended with the resin are as much as possible. , The risk of lowering the mechanical strength of the resin is as small as possible. Therefore, it is useful as a filler for various resins such as a curable epoxy resin, a silicone resin, and a thermoplastic resin, and particularly extremely useful as a filler for an epoxy resin composition for semiconductor encapsulation.

The epoxy resin composition of the present invention containing such an inorganic filler for a resin will be described below. The epoxy resin composition of the present invention comprises an epoxy resin, a curing agent and the above-mentioned inorganic filler for a resin as main components. It is blended.

Here, as the epoxy resin, any epoxy resin having at least two epoxy groups in one molecule can be used. Specifically, bisphenol A type epoxy resin, phenol novolak type epoxy resin Resin, triphenol alkane type epoxy resin and its polymer, biphenyl type epoxy resin, dicyclopentadiene-phenol novolak resin, phenol aralkyl type epoxy resin, naphthalene ring-containing epoxy resin, glycidyl ester type epoxy resin, alicyclic epoxy resin, Heterocyclic epoxy resins, brominated epoxy resins, and the like can be used. Among these epoxy resins, a naphthalene ring-containing epoxy resin and a biphenyl-type epoxy resin are preferable in that low moisture absorption and high adhesiveness are obtained. The use of these epoxy resins is not necessarily limited to one type, and two or more types may be used in combination.

The curing agent is not particularly limited and can be appropriately selected depending on the epoxy resin used. Examples thereof include amine-based curing agents, acid anhydride-based curing agents, phenol novolak resins, and cresol novolak resins. And the like, and among them, a phenol novolak-type curing agent is preferable.

The compounding amount of the curing agent is an amount capable of curing the epoxy resin, and may be a commonly used amount.
When a phenol novolak type curing agent is used, it is preferable to mix the epoxy group in the epoxy resin and the OH group in the curing agent such that the molar ratio is 1: 0.5 to 1: 1.5. .

In the present invention, various curing accelerators, for example, imidazoles, tertiary amines, phosphine compounds, cycloamidine compounds and the like can be blended for the purpose of accelerating the reaction between the epoxy resin and the curing agent. . The amount of the curing accelerator is not particularly limited, but is usually preferably about 0.05 to 1% by weight based on the whole system.

Further, in the present invention, a silicone polymer may be blended in the composition for the purpose of reducing the stress of the cured product. When a silicone-based polymer is blended, the occurrence of package cracks in a thermal shock test of the cured product can be significantly reduced. Examples of the silicone polymer include a silicone oil having an epoxy group, an amino group, a carboxyl group, a hydroxyl group, a hydrosilyl group, a vinyl group and the like, a silicone resin, a silicone rubber and the like, and a silicone polymer and an organic polymer such as a substituted or unsubstituted polymer. And phenol novolak resins.

The addition amount of the silicone polymer is not particularly limited, but it is usually preferable that the addition amount is 1 to 50 parts based on 100 parts of the total amount of the epoxy resin and the curing agent.

Further, for the purpose of imparting flexibility and toughness to the cured product, thermoplastic resins such as various organic synthetic rubbers, methyl methacrylate-styrene-butadiene copolymer, styrene-ethylene-butene-styrene copolymer, etc. A resin can be added, whereby a low stress can be applied to the cured product.

The epoxy resin composition of the present invention contains the above-mentioned inorganic filler for a resin. The compounding amount is 70 to 94% by weight based on the whole epoxy resin composition.
In particular, it is preferably in the range of 75 to 92% by weight. If the amount is less than 70% by weight, the resulting cured product may have an increased coefficient of expansion, resulting in poor stress characteristics. On the other hand, if the amount exceeds 94% by weight, the melt viscosity during molding may increase. This may cause voids and unfilled portions.

The epoxy resin composition of the present invention may further contain various additives, if necessary. For example, waxes such as carnauba wax, release agents such as fatty acids such as stearic acid and metal salts thereof ( Above all, carnauba wax is preferably used from the viewpoint of adhesiveness and releasability), organic rubber-based flexibility-imparting agents, pigments such as carbon black, cobalt blue, red iron oxide, antimony oxide and halogen compounds, etc. Agent, a silane coupling agent such as γ-glycidoxypropyltrimethoxysilane, an antioxidant, and one or more other additives.

In preparing the epoxy resin composition of the present invention, predetermined amounts of the above-mentioned components are uniformly stirred and mixed, and kneaded with a kneader, roll, extruder or the like, which has been heated to 70 to 95 ° C., and cooled. Then, it can be obtained by a method such as pulverization, but a melt-mixing method using a mixing roll or an extruder is particularly preferably employed. Here, there is no particular limitation on the mixing order of each component.

The epoxy resin composition of the present invention thus obtained is a DIP type, a flat pack type, a PLCC type,
This is effective for a semiconductor package such as an O-type package. In this case, it can be performed by a molding method conventionally used, for example, transfer molding, injection molding, casting method, or the like. The molding temperature of the epoxy resin composition of the present invention is 150 to 180 ° C, and the post cure is 150 to 185.
C. for 2 to 6 hours.

[0033]

The inorganic filler for a resin of the present invention has a low viscosity in a molten state at room temperature or high temperature, has a good fluidity even when incorporated in a large amount into a resin, and is free from the formation of aggregates of the inorganic filler. It can provide as little resin composition as possible.

The epoxy resin composition of the present invention contains a large amount of an inorganic filler, can reduce the hygroscopicity as much as possible, has a low viscosity in a molten state from room temperature to high temperature, and has a low flow property. It is good, and the aggregate of the inorganic filler in the composition is as small as possible, so that it can be suitably used for semiconductor encapsulation.

[0035]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight.

Examples 1 to 3 and Comparative Examples 1 to 3 Various inorganic fillers and .gamma.-glycidoxypropyl trialkoxysilane shown in Table 1 were mixed in an amount shown in Table 1 using a Henschel mixer. A filler mixture was prepared.

The treatment method and the method for measuring the filler aggregate in the table are shown below. <Treatment method> (A): After only the filler shown in A in Table 1 was mixed for 5 minutes, silane coupling treatment was performed by spraying using γ-glycidoxypropyl trialkoxysilane, and then mixed for 10 minutes. Then, after being left at room temperature for one day, a 100 mesh sieve treatment was performed. Thereafter, the filler indicated by B in the ratio shown in Table 1 was added, mixed for 20 minutes, and then sieved with a 100 mesh sieve. (A + B): After all the fillers were mixed for 5 minutes, they were subjected to a silane coupling treatment by spraying, then mixed for 10 minutes, left at room temperature for 1 day, and then sieved with a 100 mesh sieve. <Filler Aggregate Measurement Method> A solution obtained by dissolving 100 g of the obtained inorganic filler mixture in 300 g of acetone was used for 200 parts.
The weight on the sieve when passing through the mesh sieve with washing with acetone was measured, and this weight was expressed as a percentage of the total weight.

Next, an epoxy equivalent of 198 and a softening point of 60 ° C.
51 parts of an epoxidized cresol novolak resin, 6 parts of a brominated epoxidized phenol novolak resin having an epoxy equivalent of 280, 33 parts of a phenol novolak resin having a phenol equivalent of 110 and a softening point of 90 ° C., and 60 parts of a compound represented by the following formula (a): 10 parts of a reaction product with 40 parts of a compound represented by the following formula (b), 0.65 of triphenylphosphine
Parts, antimony trioxide 10 parts, carnauba wax 1.2
Part, γ-glycidoxypropyltrimethoxysilane
0 parts, 1 part of carbon and 400 parts of the inorganic filler mixture obtained by the above method are blended, melt-mixed with a mixing roll at 80 ° C. for 5 minutes, formed into a sheet, taken out, and cooled and pulverized to obtain a composition. I got

[0039]

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The obtained composition was subjected to the following tests (a) to (d). The results are also shown in Table 1. (A) Agglomerate in the composition A powder obtained by dissolving 100 g of the composition powder in 300 g of acetone was passed through a 200-mesh sieve while washing with acetone, and the weight on the sieve was measured to obtain an aggregate. (B) Melt viscosity Using a high flow type flow tester manufactured by Shimadzu Corporation at 175 ° C,
The viscosity at a load of 10 kg was measured. (C) Spiral flow Using a mold conforming to the EMMI standard, 175 ° C, 70k
It was measured under the condition of gf / cm ² . (D) Bending strength 175 ° C, 70 kgf / according to JIS-K6911
A bending rod of 10 × 4 × 100 mm was molded under the conditions of cm ² and molding time of 2 minutes, and measured at room temperature.

[0041]

[Table 1]

From Table 1, a comparison between Example 1 using the same two types of silica and Comparative Example 1 shows that both of the two types of silica were treated with an alkoxy group-containing silane (Comparative Example 1). Has a large amount of aggregates, and as a result, the bending strength is low. On the other hand, when only one of the two types of silica having a larger particle diameter is treated with an alkoxy group-containing silane (Example 1), the amount of aggregates is small. It is recognized that the melt viscosity is low and the bending strength is high. Further, when silica having a small particle size is not added (Comparative Examples 2 and 3), it is recognized that the melt viscosity is very high and the fluidity is poor (the spiral flow is low).

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshio Shiohara 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory (56) References JP-A-5-32867 ( JP, A) JP-A-6-25511 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 63/00 C08K 3/00-13/08

Claims (3)

(57) [Claims] (A) 100 parts by weight of a surface-treated filler obtained by treating 100 parts by weight of an inorganic filler having an average particle diameter of 5 to 40 μm with a silane containing an alkoxy group and a glycidoxy group or a partial hydrolyzate thereof; B) An inorganic filler for a resin, which is obtained by mixing 1 to 40 parts by weight of an inorganic filler having an average particle diameter of 4 μm or less, which has not been subjected to surface treatment. 2. The resinous inorganic filler according to claim 1, wherein the inorganic filler is selected from fused silica, crystalline silica, alumina, silicon nitride and aluminum nitride. 3. An epoxy resin composition comprising an epoxy resin, a curing agent and an inorganic filler, wherein the inorganic filler for a resin according to claim 1 or 2 is used as the inorganic filler. Epoxy resin composition.