JP2660999B2 - Resin composition for sealing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a resin composition for sealing electronic and electric parts having excellent moisture resistance and solder heat resistance.

(Prior Art) In recent years, in the field of semiconductor integrated circuits, automation of a mounting process of a semiconductor device has been promoted at the same time as development of technology for higher integration and higher reliability. For example, when attaching a flat package type semiconductor device to a circuit board, soldering has conventionally been performed for each lead pin, but recently, the entire semiconductor device has been immersed in a solder bath heated to 250 ° C or higher, and soldering has been performed. The method of doing is adopted.

(Problems to be Solved by the Invention) In a conventional semiconductor device sealed with a resin composition comprising an epoxy resin, a novolak-type phenol resin, and an inorganic filler, if the entire device is immersed in a solder bath, the moisture resistance is reduced. There were drawbacks.

In particular, when a semiconductor device that has absorbed moisture is immersed in solder, the interface between the inorganic filler and the resin in the sealing resin is separated from the resin, causing significant moisture resistance deterioration, disconnection and leakage current due to electrode corrosion, and long-term reliability. There is a disadvantage that it cannot be guaranteed.

By the way, in general, it is known to use a silane coupling agent for modifying a material composed of an organic-inorganic hybrid system, that is, for improving mechanical strength, improving water resistance, and improving electric properties after immersion. It is also used in the sealing resin composition of the device. However, silane coupling agents used in conventional sealing resin compositions are those in which a carbon functional group and a silicon functional group are linked by an aliphatic skeleton, and the sealing resin having the above-mentioned disadvantages The composition used such a silane coupling agent.

The present invention has been made to solve the above disadvantages, excellent in moisture resistance and solder heat resistance after immersion in a solder bath,
An object of the present invention is to provide a sealing resin composition that can withstand long-term reliability without peeling of an interface or disconnection due to corrosion.

[Constitution of the Invention] (Means for Solving the Problems) As a result of intensive studies to achieve the above object, the present inventors have found that an inorganic filler which is a component of a sealing resin has an aromatic skeleton. The inventors have found that a resin composition having good moisture resistance and solder heat resistance can be obtained by treating with a coupling agent having good heat resistance, and the present invention has been completed.

That is, the present invention provides (A) an epoxy resin, (B) a novolak-type phenol resin, and (C) a coupling agent represented by the following general formula. (Wherein, R ¹ represents an amino group, a hydroxyl group or a glycidyloxy group, R ² represents a methyl group or an ethyl group, and n represents an integer of 0, 1 or 2). (D) Inorganic filler (D) as an essential component, based on the whole resin composition.
A sealing resin composition containing 25 to 90% by weight of an inorganic filler.

The epoxy resin (A) used in the present invention is not particularly limited in molecular structure, molecular weight, etc., as long as it has at least two epoxy groups in its molecule, and those generally used as a sealing material are used. Can be widely encompassed. For example, bisphenol-type aromatic resins, alicyclic resins such as cyclohexane derivatives, and epoxy novolak resins represented by the following general formulas may be used.

(Wherein, R ¹ represents a hydrogen atom, a halogen atom or an alkyl group, R ² represents a hydrogen atom or an alkyl group, and n represents an integer of 1 or more) These epoxy resins may be used alone or in combination of two or more. Can be used.

As the novolak type phenol resin (B) used in the present invention, novolak type phenol resins obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde, and modified resins thereof, for example, epoxidized or butylated novolak type Phenol resins and the like can be mentioned, and these resins can be used alone or as a mixture of two or more. The compounding ratio of the novolak type phenol resin is
The equivalent ratio [(a) / (b)] between (A) the epoxy group (a) of the epoxy resin and (B) the phenolic hydroxyl group (b) of the novolak type phenol resin is in the range of 0.1 to 10. It is desirable. Equivalent ratio is less than 0.1 or 1
If it exceeds 0, the moisture resistance, the molding workability and the electrical properties of the cured product will be poor, and any case is not preferred. Therefore, it is preferable to limit to the above range.

The coupling agent (C) used in the present invention has good heat resistance having the following general formula.

(Wherein, R ¹ represents an amino group, a hydroxyl group or a glycidyloxy group, R ₂ represents a methyl group or an ethyl group, and n represents an integer of 0, 1 or 2, respectively). Hydroxyl groups are bonded,
It has been confirmed that a glycidyl group is bonded to the novolak-type phenol resin, but it is needless to say that other functional groups that bond to the epoxy resin or the phenol resin may be used. These can be used alone or in combination of two or more.

As a method of compounding the coupling agent, a method in which the inorganic filler is treated in advance with the coupling agent, or a method in which the coupling agent is dissolved in an epoxy resin or a novolak type phenol resin, and the inorganic filler is added thereto There is a mixing method and the like, and any of them may be used. The addition amount of the coupling agent is appropriately calculated from the surface area of the inorganic filler.

As the inorganic filler (D) used in the present invention, silica powder, alumina, antimony trioxide, talc, calcium carbonate, titanium white, clay, mica, red iron oxide,
Glass fiber, carbon fiber and the like can be mentioned, and these are used alone or as a mixture of two or more. Among these, silica powder is particularly preferably used. The compounding ratio of the inorganic filler is preferably in the range of 25 to 90% by weight based on the whole resin composition. If the proportion is less than 25% by weight, there is no effect on moisture resistance, heat resistance, mechanical properties and moldability.
Poor moldability and not suitable for practical use.

The encapsulating resin composition of the present invention contains an epoxy resin, a novolak-type phenol resin, a coupling agent and an inorganic filler as essential components, but, as long as it does not contradict the purpose of the present invention, if necessary, a natural wax. , Synthetic waxes, metal salts of straight-chain fatty acids, release agents such as acid amides, esters, paraffins, flame retardants such as chlorinated paraffins, bromotoluene, hexabromobenzene, antimony trioxide, carbon black, red iron oxide Colorants, such as
A silane coupling agent, various effect promoters, and the like can be appropriately added and blended.

A general method for producing the encapsulating resin composition of the present invention as a molding material includes an epoxy resin, a novolak type phenol resin, an inorganic filler surface-treated with a coupling agent, and other raw materials having a predetermined composition. After mixing sufficiently by a mixer or the like, the mixture is further melt-mixed by a hot roll, or mixed by a kneader or the like, and then cooled and solidified and pulverized to an appropriate size to obtain a molding material. it can. The molding material thus obtained is
For sealing electronic parts or electric parts,
It can be applied to insulation and the like.

(Action) The sealing resin composition of the present invention is immersed in a solder bath because the surface of the inorganic filler is covered with a coupling agent having good heat resistance by using a specific coupling agent. Also, no separation occurs at the interface with the sealing resin, that is, the epoxy resin or the phenol resin. As a result, it becomes difficult for water to enter from the outside. In addition, outflow of impurity ions such as chlorine ions and sodium ions from the inorganic filler is suppressed, and deterioration of moisture resistance after solder immersion is reduced.

(Examples) Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to the examples. In the following Examples and Comparative Examples, “%” means “% by weight”.

Example Cresol novolak epoxy resin (epoxy equivalent 21
5) 18%, 9% of novolak type phenol resin (phenol equivalent 107), 0.4% of coupling agent represented by the following formula, 72% of fused silica powder, 0.3% of a curing accelerator, and 0.3% of an ester wax were mixed at room temperature, kneaded at 90 to 95 ° C, cooled, and pulverized to produce a molding material (A).

Comparative Example Cresol novolak epoxy resin (epoxy equivalent 21
5) Novolak type phenol resin (phenol equivalent 107) 9%, silica powder 71%, hardening accelerator 0.3%, ester wax 0.3% and silane coupling agent 0.4% represented by the following structure in 19%, Was prepared in the same manner as in the Examples to produce a molding material (B).

Molding materials (A) obtained in Examples and Comparative Examples
Using (B), transfer was injected into a mold heated to 170 ° C., cured, and sealed to obtain a molded product. The molded article was subjected to a moisture resistance test, and the results were obtained. The results are shown in Table 1. The remarkable effects of the present invention were confirmed.

*: Using a molding material of the sample, a silicon chip with two or more aluminum wirings is bonded to a normal 42 alloy frame and transfer molded at 175 ° C for 2 minutes, and a 5 × 10 × 1.5 mm flat package A molded article was obtained and then post-cured at 175 ° C. for 8 hours. After preliminarily subjecting this molded article to moisture absorption treatment at 40 ° C, 90% RH and 100 hours,
C. for 10 seconds. Thereafter, a pressure cooker test was performed in saturated steam at 127 ° C. and 2.5 atm, and disconnection due to corrosion of the aluminum wiring was evaluated as defective.

[Effects of the Invention] As is clear from the above description and Table 1, the encapsulating resin composition of the present invention has excellent moisture resistance because no separation occurs at the interface between the resin and the inorganic filler, and the Even after immersion in a bath, there is little deterioration in moisture resistance, there is no disconnection or leakage current due to corrosion, and reliability can be guaranteed for a long time.

Claims (1)

(57) [Claims] (A) an epoxy resin; (B) a novolak type phenolic resin; and (C) a coupling agent represented by the following general formula. (Wherein, R ¹ represents an amino group, a hydroxyl group or a glycidyloxy group, R ² represents a methyl group or an ethyl group, and n represents an integer of 0, 1 or 2). (D) Inorganic filler (D) as an essential component, based on the whole resin composition.
A resin composition for sealing, comprising 25 to 90% by weight of an inorganic filler.