JPH0820673A - Inorganic filler for resin and epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain an inorganic filler consisting of a specific composition, having a low viscosity at a room temperature or when melted at a high temperature even in the case where a large amount of the filler is compounded into an epoxy resin, etc., excellent in fluidity and little in aggregate generation when added to a resin. CONSTITUTION:This filler is obtained by compounding (A) 100 pts.wt., of a surface-treated filler obtained by treating 100 pts.wt. of an inorganic filler (e.g. crystalline silica and alumina) having an average particle diameter of 5-40mum with an alkoxy-containing silane (e.g. 3-glycidoxypropyltrimethoxysilane or phenyltrimethoxysilane) or its partially hydrated substance with (B) 1-40 pts.wt. of an inorganic filler which is not treated with the alkoxy-containing silane or its partially hydrated material and having an average diameter of <=4mum. Further, the amount of the alkoxy-containing silane used in the component A is preferably 0.1-0.6 pts.wt. based on 100 pts.wt. of the inorganic filler. The mixture of the component A with the component B is preferably passed through a 100-200 mesh sieve to remove aggregates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention provides a resin composition which has a low viscosity at room temperature to a high temperature in a molten state and has good flow characteristics even when it is mixed in a large amount with an epoxy resin for the purpose of lowering hygroscopicity. Among them, the present invention relates to an inorganic filler for a resin that rarely gives an aggregate and an epoxy resin composition using the filler.

[0002]

2. Description of the Related Art
In the semiconductor industry, resin-encapsulated diodes, transistors, ICs, LSIs, and VLSIs are the mainstream, and epoxy resin is generally used as the encapsulating resin in comparison with other thermosetting resins in terms of moldability and adhesiveness. Because of its excellent electrical properties, mechanical properties, moisture resistance, etc., semiconductor devices are often sealed with epoxy resin compositions.

Recently, the degree of integration of these semiconductor devices has been increasing, and the chip size has been increasing accordingly. On the other hand, the external dimensions of the package are becoming thinner along with the demand for smaller and lighter electronic devices. Further, also in the method of mounting a semiconductor component on 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 the semiconductor device is surface-mounted, a method of immersing the entire semiconductor device in a solder bath or passing it through a zone where the solder is melted is generally used. However, the thermal shock at that time causes a sealing resin layer. Cracks may occur, or peeling may occur at the interface between the lead frame or chip and the sealing resin. Such cracks and peeling become more noticeable if the sealing resin layer of the semiconductor device absorbs moisture before the thermal shock during surface mounting, but in the actual working process, the moisture absorption of the sealing resin layer Inevitably, the reliability of the semiconductor device sealed with the epoxy resin after mounting may be greatly impaired.

Under these circumstances, a low hygroscopic encapsulating resin has been required in order to reduce moisture absorption of the encapsulating resin layer and prevent cracks and peeling during surface mounting. It is known that adding a large amount of an inorganic filler is effective 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 increases and the flow characteristics deteriorate, but when the above-mentioned semiconductor device is transfer molded. The melt viscosity of the resin composition should be as low as possible.

In this case, in order to lower the melt viscosity, a method of using a filler having a large particle diameter and a filler having a small particle diameter in combination is known, and in order to control the interface between the resin and the inorganic filler. , There are known methods of surface-treating an inorganic filler with a silane coupling agent. However, even with these methods, the decrease in the viscosity in the molten state at room temperature to high temperature is insufficient, and the aggregate of the inorganic filler is large. However, there is a problem in that the mechanical strength of the cured product decreases.

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

[0009]

Means and Action for Solving the Problems The present inventors have
As a result of extensive studies to achieve the above object, 100 parts by weight of an inorganic filler having an average particle diameter of 5 to 40 μm treated with an alkoxy group-containing silane or a partial hydrolyzate thereof, and 100 parts by weight of an alkoxy It has been found that a filler obtained by mixing 1 to 40 parts by weight of an inorganic filler having an average particle size of 4 μm or less, which is not surface-treated with a group-containing silane or a partial hydrolyzate thereof, is effective.

That is, it is conventionally known to use fillers having different average particle sizes together, and it is also known to treat the surface of an inorganic filler with an alkoxy group-containing silane or a partial hydrolyzate thereof. The inventors have tried to combine these with fillers having different average particle sizes and treat each with an alkoxy group-containing silane or a partial hydrolyzate thereof, but the fluidity is good,
While there are many filler agglomerates and therefore the mechanical strength of the cured product is inferior, when using fillers with different average particle diameters, only the larger particle diameter is used for the alkoxy group-containing silane or its portion. Treated with a hydrolyzate, by mixing these with a smaller particle size without surface treatment with an alkoxy group-containing silane or a partial hydrolyzate thereof, surprisingly less agglomerates when compounded into the resin, Further, they have found that the viscosity is low at room temperature to high temperature melting and the fluidity is good, and the present invention has been completed.

Therefore, the present invention provides (A) an average particle size of 5-4.
100 parts by weight of a 0 μm inorganic filler treated with an alkoxy group-containing silane or a partial hydrolyzate thereof, and 100 parts by weight of a filler (B) which is not surface-treated with an alkoxy group-containing silane or a partial hydrolyzate thereof. Average particle size 4
An inorganic filler for resin, characterized by being mixed with 1 to 40 parts by weight of an inorganic filler having a size of μm or less, and an epoxy resin composition containing an epoxy resin, a curing agent, and an inorganic filler, There is provided an epoxy resin composition characterized by using the inorganic filler for resin as the inorganic filler.

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

In the present invention, the inorganic filler as the component (A) has an average particle size of 5 to 40 μm, preferably 7 to 30 μm.
It must be within the range of m. If the average particle size is smaller than 5 μm, the effect of using the inorganic filler having a smaller average particle size of the component (B) will not be exhibited, while if the average particle size is larger than 40 μm, the fluidity at the time of melting will be deteriorated. As the type of inorganic filler that can be used, conventionally known inorganic fillers can be used, and examples thereof include crushed or spherical fused silica, crystalline silica, alumina, silicon nitride, and aluminum nitride. it can. Also, the average particle size, material,
Two or more kinds of inorganic fillers having different shapes may be used in combination, and in order to achieve both low expansion of the cured product and moldability, spherical products and crushed products are used in combination, or only spherical products are used. Recommended.

As the alkoxy group-containing silane for treating such an inorganic filler, conventionally known ones can be used, for example, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 1,
3-bis (γ-glycidoxypropyl) -1,1,3
3-tetramethoxy-1,3-disiloxane, 1,3-
Dimethyl-1,1,3,3-tetramethoxy-1,3-
Examples thereof include disiloxane, phenyltrimethoxysilane, and methyltriethoxysilane, and partial hydrolysates of these can also be used.

The amount of the alkoxy group-containing silane or its partial hydrolyzate used is preferably 0.1 to 1 part, and more preferably 0.1 to 0 part, relative to 100 parts (parts by weight, the same hereinafter) of the inorganic filler. The range is 6 parts. If the amount used 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. On the other hand, if the amount used is more than 1 part, aggregates may form. May be easier.

The method for preparing the surface-treated filler as the component (A) is not particularly limited, but an alkoxy group-containing silane or an alkoxy group-containing silane can be added to the inorganic filler placed in a known mixer such as a Henschel mixer by a spraying means or the like. It can be obtained by sprinkling the partial hydrolyzate and then mixing the inorganic filler. Although it may be mixed with the inorganic filler of the component (B) as it is, it is allowed to stand at room temperature for several days in order to further reduce agglomerates, or after heat treatment, 100
It is preferred to remove agglomerates through a ~ 200 mesh screen.

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, In addition to crystalline silica, alumina, silicon nitride, aluminum nitride and the like can be mentioned.
Moreover, you may use together 2 or more types of inorganic fillers from which an average particle diameter, a material, and a shape differ.

The amount of the inorganic filler as the component (B) used should be in the range of 1 to 40 parts, preferably 3 to 30 parts, relative to 100 parts of the surface-treated inorganic filler as the component (A). . If the amount used is less than 1 part, the viscosity at room temperature to high temperature when mixed with the resin cannot be sufficiently lowered, while if it exceeds 40 parts, it is economically disadvantageous and aggregation easily occurs. Become.

For mixing the fillers of the component (A) and the component (B), a conventionally known mixing device can be used. Specific examples thereof include mixers such as a Henschel mixer, a vertical mixer, a ball mill and a concrete mixer. After mixing, it is preferable to remove aggregates with a 100-200 mesh screen.

When a large amount of the inorganic filler for a resin of the present invention is blended with the resin, it has a low viscosity at room temperature to a high temperature and maintains good fluidity, and aggregates when blended with the resin as much as possible. Since it is extremely small, the possibility 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 curable epoxy resin, silicone resin, and thermoplastic resin, and is especially useful as a filler for epoxy resin composition for semiconductor encapsulation.

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

As the epoxy resin, any epoxy resin can be used as long as it is an epoxy resin having at least two epoxy groups in one molecule, specifically, bisphenol A type epoxy resin and phenol novolac type epoxy resin. Resin, triphenolalkane type epoxy resin and its polymer, biphenyl type epoxy resin, dicyclopentadiene-phenol novolac resin, phenol aralkyl type epoxy resin, naphthalene ring-containing epoxy resin, glycidyl ester type epoxy resin, alicyclic epoxy resin, A heterocyclic epoxy resin, a brominated epoxy resin, etc. can be used. Among these epoxy resins, naphthalene ring-containing epoxy resin and biphenyl type epoxy resin are preferable from the viewpoint of obtaining low moisture absorption and high adhesiveness. It should be noted that these epoxy resins are not necessarily limited to one kind in use, and two or more kinds may be mixed and used.

The curing agent is not particularly limited and can be appropriately selected depending on the epoxy resin used, and examples thereof include amine curing agents, acid anhydride curing agents, phenol novolac resins, cresol novolac resins. Examples thereof include phenol novolac type curing agents, and among them, phenol novolac type curing agents are preferable.

The compounding amount of the curing agent is an amount capable of curing the epoxy resin, and can be an amount usually used,
When a phenol novolac type curing agent is used, it is preferable to mix it so that the molar ratio of the epoxy groups in the epoxy resin to the OH groups in the curing agent is 1: 0.5 to 1: 1.5. .

In the present invention, various curing accelerators such as imidazoles, tertiary amines, phosphine compounds and cycloamidine compounds may be added for the purpose of accelerating the reaction between the epoxy resin and the curing agent. . The compounding amount of the curing accelerator is not particularly limited, but usually it is preferable to be about 0.05 to 1% by weight based on the whole system.

Furthermore, in the present invention, a silicone polymer may be added to the composition for the purpose of reducing the stress of the cured product. When a silicone-based polymer is blended, it is possible to significantly reduce the occurrence of package cracks in the thermal shock test of the cured product. Examples of the silicone-based polymer include 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 these silicone polymers and organic polymers, for example, substituted or unsubstituted. Examples thereof include polymers such as phenol novolac resins.

The addition amount of the silicone-based polymer is not particularly limited, but it is usually preferably 1 to 50 parts per 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, thermoplastics such as various organic synthetic rubbers, methyl methacrylate-styrene-butadiene copolymers, styrene-ethylene-butene-styrene copolymers, etc. A resin can be added, which can impart low stress to the cured product.

The above-mentioned inorganic filler for resin is blended in the epoxy resin composition of the present invention, and the blending amount thereof 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 blending amount is less than 70% by weight, the expansion coefficient of the obtained cured product becomes large and the stress characteristics may deteriorate. On the other hand, if it exceeds 94% by weight, the melt viscosity at the time of molding becomes high. There is a possibility that voids, unfilling, etc. may occur due to excessive flow.

If desired, various additives may be added to the epoxy resin composition of the present invention. For example, waxes such as carnauba wax, fatty acids such as stearic acid and release agents such as metal salts thereof ( Among them, carnauba wax is preferably used in terms of adhesiveness and releasability), organic rubber-based flexibility-imparting agents, pigments such as carbon black, cobalt blue and red iron oxide, antimony oxide, and flame retardant halogen compounds. One or two or more types of agents, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, antiaging agents, and other additives can be added.

In the production of 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 preheated to 70 to 95 ° C., and cooled. It can be obtained by a method such as pulverization and pulverization, and a melt mixing method using a mixing roll and an extruder is particularly preferably used. Here, there is no particular limitation on the order of mixing the components.

The epoxy resin composition of the present invention thus obtained is a DIP type, a flat pack type, a PLCC type, an S type.
It is effective for semiconductor packages of O type and the like, and in this case, it can be performed by a conventionally used molding method, 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.
It is preferable to carry out at 2 ° C for 2 to 6 hours.

[0033]

INDUSTRIAL APPLICABILITY The inorganic filler for a resin of the present invention has a low viscosity at room temperature to a high temperature molten state even when it is blended in a large amount in a resin, has good flow characteristics, and does not generate aggregates of the inorganic filler. It is possible to provide a resin composition that is as small as possible.

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

[0035]

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 following examples, all parts are parts by weight.

[Examples 1 to 3 and Comparative Examples 1 to 3] Various inorganic fillers shown in Table 1 and γ-glycidoxypropyltrialkoxysilane were mixed in the amounts shown in Table 1 by using a Henschel mixer. A filler mixture was prepared.

The treatment methods in the table and the measuring method of filler aggregates are shown below. <Treatment Method> (A): After mixing only the fillers indicated by A in Table 1 for 5 minutes, silane coupling treatment is performed by using γ-glycidoxypropyltrialkoxysilane by spraying, and then mixing for 10 minutes. Then, it was allowed to stand at room temperature for 1 day and then subjected to 100-mesh sieving. Then, the filler shown 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, silane coupling treatment was performed by spraying, then mixed for 10 minutes, and allowed to stand at room temperature for 1 day, followed by sieving treatment with a 100 mesh sieve. <Filler aggregate measuring method> 200 g of the obtained inorganic filler mixture dissolved in 300 g of acetone is 200
The weight on the sieve when passing through the mesh sieve while being washed with acetone was measured, and this weight was expressed as% of the total weight.

Next, the epoxy equivalent is 198 and the softening point is 60 ° C.
51 parts of epoxidized cresol novolac resin, 6 parts of brominated epoxidized phenol novolac resin having an epoxy equivalent of 280, phenol equivalent of 110, 33 parts of phenol novolac resin having 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 1.
0 parts, 1 part of carbon, and 400 parts of the inorganic filler mixture obtained by the above method were mixed, melt-mixed with a mixing roll at 80 ° C. for 5 minutes, taken out as a sheet, cooled and pulverized to obtain a composition. Got

[0039]

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The following tests (a) to (d) were conducted on the obtained composition. The results are also shown in Table 1. (A) Aggregate in composition A powder obtained by dissolving 100 g of the powder of the composition in 300 g of acetone was passed through a 200 mesh sieve while washing with acetone, and the weight on the sieve was weighed to obtain an aggregate. (B) Melt viscosity 175 ° C using a Shimadzu high-performance flow tester,
The viscosity under a load of 10 kg was measured. (C) Spiral flow 175 ° C, 70k using a mold conforming to EMMI standard
It was measured under the condition of gf / cm ² . (D) Bending strength According to JIS-K6911, 175 ° C, 70 kgf /
A bending bar having a size of 10 × 4 × 100 mm was molded under the conditions of cm ² and a 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 types of silica were treated with an alkoxy group-containing silane (Comparative Example 1). Has a large amount of agglomerates, resulting in low bending strength, whereas when only one of the two types of silica having a larger particle size is treated with the alkoxy group-containing silane (Example 1), less agglomerates are obtained. It is recognized that the melt viscosity is low and the bending strength is high. Further, it is recognized that unless silica having a small particle size is blended (Comparative Examples 2 and 3), the melt viscosity is very high and the fluidity is poor (the spiral flow is low).

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshio Shiobara 1 Hitomi, Oita, Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (2)

[Claims] 1. (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 an alkoxy group-containing silane or a partial hydrolyzate thereof, and (B) containing an alkoxy group. An inorganic filler for resin, characterized by being mixed with 1 to 40 parts by weight of an inorganic filler having an average particle size of 4 μm or less which is not surface-treated with silane or a partial hydrolyzate thereof. 2. An epoxy resin composition comprising an epoxy resin, a curing agent and an inorganic filler, wherein the inorganic filler for resin according to claim 1 is used as the inorganic filler. Resin composition.