JPH04246412A - Sealing resin composition and semiconductor sealing apparatus - Google Patents

Abstract

PURPOSE:To obtain the title compsn. with excellent moldability, moisture resistance and solder heat resistance of thin parts by incorporating each specified epoxy resin, phenolic resin, phosphine and silica powder as essential ingredients and incorporating a specified amt. of the phosphine. CONSTITUTION:The title compsn. is prepared by incorporating an epoxy resin of formula I (wherein R is H or an alkyl), a novolak-type phenolic resin, a tris(o,p-substd. phenylphosphine of formula II (wherein R<1>-R<3> are each an electron-donating group or H and one or more of then are electron-donating groups) [e.g. tris(2,6-diethoxyphenylphosphine] and silica powder as essential ingredients and incorporating the phosphine in an amt. of 0.01-5wt.% based on the resin compsn.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for sealing which has good moldability and excellent moisture resistance and soldering heat resistance, and a semiconductor sealing device sealed with the same.

0002

2. Description of the Related Art In recent years, the practical use of thin packages has been promoted for semiconductor devices. For example, flat packages in integrated circuits, SOP (smalloutl...
ine package), TSOP(thins
(mall outline package), and isolation type packages for power transistors, etc., the thin part of about 0.1 to 0.5 mm, such as the top surface of the semiconductor element or the back surface of the insulation type package, must be filled with resin. It is no longer true. On the other hand, surface-mount packages use a solder dipping method or a solder reflow method when attaching them to a circuit board, creating an even harsher environment for the sealing resin that makes up the package.

Conventional sealing resins are composed of novolac type epoxy resin, novolac type phenol resin, silica powder, and a known curing accelerator, but when sealed with this sealing resin, the resin is deposited in thin parts. It has disadvantages such as poor moldability such as not being filled, causing cavities and blisters, and a decrease in moisture resistance and poor appearance. Further, the semiconductor device sealed with the conventional sealing resin described above has a drawback in that moisture resistance decreases when the entire device is immersed in a solder bath or the like. In particular, if a semiconductor device that has absorbed moisture is immersed in a solder bath, peeling may occur between the encapsulating resin and the semiconductor element, between the encapsulating resin and the lead frame, or internal resin cracks may occur, resulting in significant deterioration of moisture resistance and corrosion of the electrodes. This causes wire breakage and leakage current due to moisture. As a result, the semiconductor device has the disadvantage that long-term reliability cannot be guaranteed.

0004

[Problems to be Solved by the Invention] The present invention has been made in order to eliminate the above-mentioned drawbacks. The object of the present invention is to provide a sealing resin composition and a semiconductor sealing device that have excellent moisture resistance and soldering heat resistance and can guarantee long-term reliability.

[0005]

[Means for Solving the Problems] As a result of intensive research aimed at achieving the above object, the present inventors have found that by using a composition as described below, the moldability of thin-walled parts, moisture resistance, and solderability can be improved. The present invention was completed by discovering that a sealing resin composition and a semiconductor sealing device with excellent heat resistance can be obtained.

That is, the present invention provides (A) an epoxy resin represented by the following formula:

[0007]

[Formula 5] (wherein, R represents a hydrogen atom or an alkyl group), (
B) novolac type phenolic resin, (C) tris(ortho-para substituted phenyl)phosphine represented by the following general formula

[0008]

(In the formula, R1, R2, R3 represent an electron donating group or a hydrogen atom, and at least one of R1, R2, R3 is an electron donating group.) and (D) silica powder. The above (C
This is a sealing resin composition characterized by containing 0.01 to 5% by weight of tris(ortho-para substituted phenyl)phosphine. Further, the present invention is a semiconductor sealing device characterized in that a semiconductor device is sealed with a cured product of this sealing resin composition.

The present invention will be explained in detail below.

The epoxy resin (A) used in the present invention is an epoxy resin represented by the following formula.

[0011]

embedded image (wherein R represents a hydrogen atom or an alkyl group) The epoxy resin represented by the above formula is not particularly limited by its molecular weight, etc., and can be widely used. Further, this epoxy resin can also be used in combination with an Epibis epoxy resin.

The novolak type phenol resin (B) used in the present invention includes novolak type phenol resins obtained by reacting phenols such as phenol and alkylphenols with formaldehyde or paraformaldehyde, and modified resins thereof, such as epoxidized resins. Alternatively, a butylated novolac type phenol resin may be mentioned, and as long as it is a novolak type phenol resin, there is no particular restriction and a wide range of use can be made. These resins can be used alone or in combination of two or more.

Tris(ortho/para substituted phenyl)phosphine (C) used in the present invention has the above general formula, and is triphenylphosphine substituted with an electron donating group at the ortho/para position of the phenyl group. Yes, but
It does not necessarily have to be all replaced. That is, only one ortho position, ortho and para positions, ortho and ortho positions, only para position, or two ortho and para positions. Examples of the electron donating group include an alkoxy group, an amino group, a hydroxyl group, a halogen group, and an alkyl group. Tris(ortho-para substituted phenyl)phosphine is used as a curing accelerator. In addition to this tris(ortho-para substituted phenyl)phosphine, known curing accelerators such as imidazole accelerators, diazabicycloundecene (DBU) accelerators, phosphorus accelerators, and other accelerators may be used in combination. be able to.

(C) The blending ratio of tris(ortho-para substituted phenyl)phosphine is 0.00% relative to the resin composition.
It is desirable to contain 01 to 5% by weight. If the proportion is less than 0.01% by weight, the gel time of the resin composition is long and the curing properties are also poor, which is not preferable. If it exceeds 5% by weight, fluidity becomes extremely poor and moldability becomes poor.
Moreover, the electrical properties are also deteriorated, and the moisture resistance is also inferior, which is not preferable.

As the silica powder (D) used in the present invention, commonly used silica powders are widely used, but among them, silica powders with a low impurity concentration and an average particle size of 30 μm are used.
The following are desirable. If the average particle size exceeds 30 μm, moisture resistance and moldability will be poor, which is not preferable.

The sealing resin composition of the present invention contains a specific epoxy resin, a novolac type phenol resin, a tris (ortho-para substituted phenyl) phosphine curing accelerator, and silica powder as essential components, but the object of the present invention is Within the limits not contrary to the above, and as necessary, for example, natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, etc.
Mold release agents such as esters and paraffins, flame retardants such as antimony trioxide, colorants such as carbon black, silane coupling agents, curing accelerators, rubber-based and silicone-based low stress imparting agents, etc. are added and blended as appropriate. be able to.

The general method for preparing the sealing resin composition of the present invention as a molding material is to prepare the above-mentioned components, namely, a specific epoxy resin, a novolac type phenolic resin, and tris (ortho-para substituted phenyl). Add the phosphine curing accelerator, silica powder, and other ingredients and mix thoroughly and uniformly using a mixer or the like. Further, the mixture can be melted and mixed using hot rolls or mixed using a kneader, etc., and then cooled and solidified to be crushed into a suitable size to obtain a molding material. This molding material can be applied to seal electronic or electrical parts, as well as for coating, insulation, etc., and can provide excellent properties and reliability.

The semiconductor encapsulation device of the present invention can be manufactured by encapsulating a semiconductor device using the above-mentioned encapsulation resin composition. Semiconductor devices to be sealed include, for example, integrated circuits, large-scale integrated circuits, transistors,
It is not particularly limited to thyristors, diodes, etc., and can be widely used. The most common method of sealing is
There is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting, etc. is also possible. The encapsulating resin composition is cured by heating after encapsulation molding, and a semiconductor device encapsulated by the cured product of this composition is finally obtained. Curing by heating is preferably performed at a temperature of 150° C. or higher.

[0019]

[Function] The encapsulating resin composition and semiconductor encapsulating device of the present invention achieve the intended purpose by reacting with a specific epoxy resin, novolac type phenol resin, and tris (ortho-para substituted phenyl) phosphine curing accelerator. This has been achieved. In other words, by incorporating a predetermined amount of tris (ortho-para substituted phenyl) phosphine curing accelerator and controlling the gelation time and fluidity of the resin composition, filling properties in thin-walled areas are improved, moisture resistance is improved, and excellent molding is achieved. gave gender. Further, by reacting a specific epoxy resin with a novolac type phenol resin, the glass transition temperature is raised, the properties at the time of heating are improved, and the hygroscopicity of the resin composition is reduced. As a result, even if solder immersion or solder reflow is performed, resin cracks will not occur, and in particular, moisture resistance will not deteriorate.

[0020]

EXAMPLES Next, examples of the present invention will be described, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, "%" means "% by weight".

Example 1 Specific epoxy resin 17%, novolak type phenol resin 8%, tris(2,6-diethoxyphenyl)phosphine curing accelerator 0.3%, silica powder 74%, ester wax 0.3 % and a silane coupling agent of 0.4% were mixed at room temperature, further kneaded at a temperature of 90 to 95°C, cooled, and then pulverized to produce a molding material (A).

Example 2 Specific epoxy resin 12%, novolac type phenol resin 6%, tris(2,6-diethoxyphenyl)phosphine curing accelerator 0.3%, silica powder 81%, ester wax 0.3 % and a silane coupling agent of 0.4% were mixed at room temperature, further kneaded at a temperature of 90 to 95°C, cooled, and pulverized to produce a molding material (B).

Comparative Example 1 17% o-cresol novolac type epoxy resin, 8% novolac type phenol resin, 74% silica powder, imidazole hardening accelerator 0.3%, ester wax 0.3% and silane coupling agent 0 A molding material (C) was produced in the same manner as in Example 1 except that .4% was added.

Comparative Example 2 12% o-cresol novolac type epoxy resin, 6% novolac type phenol resin, 81% silica powder, imidazole hardening accelerator 0.3%, ester wax 0.3% and silane coupling agent 0 A molding material (D) was produced in the same manner as in Comparative Example 1 except that .4% was added.

The molding materials (A) to (D) manufactured in Examples 1 to 2 and Comparative Examples 1 to 2 and the semiconductor encapsulation device manufactured using these were tested for moldability and moisture resistance, and the results are as follows. are shown in Table 1. The present invention was excellent in all cases, and the remarkable effects of the present invention could be confirmed.

[0026]

[Table 1]

[0027]

Effects of the Invention As is clear from the above explanation and Table 1, the encapsulating resin composition of the present invention has excellent moldability, is less affected by moisture absorption, and has excellent moisture resistance after immersion in a solder bath and soldering heat resistance. Because of its excellent performance, it can be easily filled into thin-walled areas without forming cavities or blisters, preventing peeling between the resin composition and the semiconductor device or between the resin composition and the lead frame, and preventing internal resin cracks from occurring, as well as preventing electrode corrosion. An excellent and highly reliable semiconductor encapsulation device was obtained, which did not cause wire breakage due to oxidation or leakage current due to moisture.

Claims (2)

[Claims] Claim 1: (A) Epoxy resin represented by the following formula: (wherein, R represents a hydrogen atom or an alkyl group), (
B) novolac type phenolic resin, (C) tris(ortho/para-substituted phenyl)phosphine represented by the following general formula [Chemical formula 2] (wherein, R1, R2, R3 represent an electron donating group or a hydrogen atom, At least one of R1, R2, and R3 is an electron-donating group) and (D) silica powder are essential components, and the above (C
1. A sealing resin composition comprising 0.01 to 5% by weight of tris(ortho-para-substituted phenyl)phosphine. Claim 2: (A) Epoxy resin represented by the following formula: (wherein, R represents a hydrogen atom or an alkyl group), (
B) novolac type phenolic resin, (C) tris(ortho/para-substituted phenyl)phosphine represented by the following general formula [Chemical formula 4] (wherein, R1, R2, R3 represent an electron donating group or a hydrogen atom, At least one of R1, R2, and R3 is an electron-donating group) and (D) silica powder are essential components, and the above (C
) A semiconductor encapsulation characterized in that a semiconductor device is encapsulated with a cured product of a encapsulation resin composition containing 0.01 to 5% by weight of tris(ortho-para substituted phenyl)phosphine. Stop device.