JPH03296523A - Resin composition for sealing and semiconductor device sealed therewith - Google Patents

Abstract

PURPOSE:To prepare the title compsn. which is improved in the resistance to soldering heat and moisture after dipping in solder, is hardly peelable from a semiconductor chip, and hence is useful for sealing a semiconductor device by compounding a specific epoxy resin, a polyhydric phenol resin, and a powdered silica. CONSTITUTION:An epoxy resin of formula I (wherein m>=0, and n>=1) is, if necessary, compounded with a novolac or bisphenol epoxy resin to give an epoxy resin compsn. Separately, a polyhydric phenol resin of formula II or III (wherein R is a group of formula IV; and m and n are each 0 or higher) is, if necessary, compounded with a (modified) novolac phenol resin to give a phenol resin compsn. Then, the epoxy resin compsn., the phenol resin compsn., 50-90wt.% powdered silica having a high purity and a mean particle diameter of 50mum or lower, and, if necessary, a mold release agent, a flame retardant, a colorant, a curing accelerator, etc., are compounded to give the title compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a sealing resin composition with excellent moisture resistance and soldering heat resistance, and a semiconductor sealing device.

(Prior Art) In recent years, in the field of semiconductor integrated circuits, the automation of the mounting process of semiconductor devices has been promoted at the same time as the development of technologies for higher integration and higher reliability. For example, when attaching a flat package type semiconductor device to a circuit board, soldering was conventionally performed for each lead bin, but recently a solder dipping method or a solder reflow method has been adopted.

(Issues to be Solved by the Invention) A semiconductor device sealed with a conventional resin composition consisting of a novolac type epoxy resin, a novolac type phenol resin, and silica powder becomes moisture resistant when the entire device is immersed in a solder bath. The disadvantage was that it decreased. In particular, if a semiconductor device that has absorbed moisture is immersed, peeling between the encapsulating resin and the semiconductor chip, between the encapsulating resin and the lead frame, and internal resin cracks will occur, resulting in a significant deterioration of moisture resistance. A leakage current is generated, and as a result, the semiconductor device has the disadvantage that long-term reliability cannot be guaranteed.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and has little influence of moisture absorption, particularly excellent moisture resistance after soldering immersion, and soldering heat resistance, and is capable of connecting a sealing resin to a semiconductor chip or a sealing resin to a lead frame. An object of the present invention is to provide a resin composition for sealing and a semiconductor sealing device that can guarantee long-term reliability without peeling or internal resin cracks, and without disconnection due to electrode corrosion or leakage current due to moisture. It is something.

[Configuration of the Invention (Means for Solving the Problems) As a result of extensive research aimed at achieving the above object, the present inventors have found that by using a specific epoxy resin and a specific polyfunctional phenol resin, The present invention was completed by discovering that a resin composition having excellent moisture resistance and soldering heat resistance can be obtained.

That is, the sealing resin composition of the present invention comprises (A) an epoxy resin represented by the following general formula, (wherein 1 represents 0 or an integer of 1 or more, and n represents an integer of 1 or more. ) (B) A polyfunctional phenolic resin represented by the following general formula (I) or (If), and (wherein, R represents CII H2m+1, and n and n represent an integer of 0 or 1 or more) (C ) A sealing resin composition comprising silica powder as an essential component and containing 50 to 90% by weight of the silica powder (C) based on the resin composition. The present invention also provides a semiconductor encapsulation device characterized in that a semiconductor element is encapsulated using this encapsulation resin composition.

The present invention will be explained in detail below.

The epoxy resin (A) used in the present invention may be one represented by the following general formula (where I represents an integer of 0 or 1 or more, and n represents an integer of 1 or more): Molecular weight, etc. There are no particular restrictions and it can be used widely. Moreover, a novolac type epoxy resin or an epibis type epoxy resin can be used in combination with this epoxy resin.

As the (B) polyfunctional phenol resin used in the present invention,
It is represented by the following general formula (wherein R is CB
H2H+1, 1. (n represents an integer of 0 or 1 or more) As long as it is at least a trifunctional or tetrafunctional phenol resin, it can be broadly included without being limited by its molecular structure, molecular weight, etc.

Examples of specific polyfunctional phenol resins include examples, and these can be used alone or in a mixture of two or more. Furthermore, in addition to the above-mentioned polyfunctional phenol resins, novolac-type phenol resins obtained by reacting phenols such as phenol and alkylphenols with formaldehyde or paraformaldehyde, and modified resins thereof can be mixed and used. .

As the silica powder (C) used in the present invention, commonly used silica powders are widely used, but among them, those with a low impurity concentration and an average particle size of 50 μm or less are preferable. If it exceeds this, moisture resistance and moldability will deteriorate, which is undesirable.

The blending ratio of silica powder is 5% to the total resin composition.
It is preferable to contain 0 to 90% by weight. If the proportion is less than 50% by weight, the resin composition will have high hygroscopicity and will have poor moisture resistance after solder immersion, and if it exceeds 90% by weight, 1g7
The fluidity becomes poor at 1v/A and the moldability is poor, which is not preferable.

The sealing resin composition of the present invention contains the above-mentioned specific epoxy resin, polyfunctional phenol resin, and silica powder as essential components, but within the range not contrary to the purpose of the present invention,
In addition, if necessary, for example, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, mold release agents such as paraffin, flame retardants such as antimony dioxide, colorants such as carbon black, silanes, etc. Coupling agents, various curing accelerators, rubber-based or silicone-based low stress imparting agents, etc. can be added and blended as appropriate.

The general method for preparing the sealing resin composition of the present invention as a molding material is to blend the above-mentioned epoxy resin, polyfunctional phenol resin, silica powder, and others, mix thoroughly and uniformly with a mixer, etc., and then 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. The semiconductor sealing device of the present invention can be manufactured by transfer-injecting this molding material into a mold in which a semiconductor element is set and curing it.

The semiconductor encapsulation device of the present invention can be easily manufactured by encapsulating a semiconductor element using the above-mentioned encapsulation resin composition. Semiconductor elements to be sealed include, but are not particularly limited to, integrated circuits, large-scale integrated circuits, transistors, thyristors, diodes, etc.
The most common method for sealing is low-pressure transfer molding, but sealing by injection molding, compression molding, casting, etc. is also possible. The sealing resin composition is heated and cured during sealing, and a semiconductor sealing device sealed with a cured product of this composition is finally obtained. For curing by heating, it is desirable to cure by heating to 150°C or higher.In addition to sealing semiconductor elements, the molding material can also be used for sealed coatings and insulation of electronic parts or electrical parts. It is possible to impart excellent properties to them.

(Function) In the present invention, by using a specific epoxy resin and a specific polyfunctional phenol resin, it was possible to increase the glass transition temperature of the resin composition and improve the thermomechanical properties and low stress properties. As a result, it is possible to produce a sealing resin composition and a semiconductor sealing device in which resin cracks do not occur after solder immersion and solder reflow, and moisture resistance deterioration is reduced.

(Examples) Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

In the following Examples and Comparative Examples, "%" means "% by weight".
” means.

Example 1 17% of the specific epoxy resin mentioned above, 10% of the polyfunctional phenol resin shown in the following formula, 72% of silica powder, imidazole curing accelerator C,,Z
O, 1%, ester wax 0.3% and silane coupling agent 0.4% are mixed at room temperature, and further 90-95%
The mixture was kneaded at °C, cooled, and then ground to produce a molding material [A].

Example 2 9% of the epoxy resin and 8% of the polyfunctional phenol resin used in Example 1, 8% of orthocresol novolac type epoxy resin, 74% of silica powder, 1% of imidazole curing accelerator C1720, and 0.0% of ester wax. 3%
and 0.4% of silane coupling agent are mixed at room temperature,
After further kneading and cooling at 90 to 95°C, the mixture was pulverized to produce a molding material [B].

Comparative Example 1 Mixing of 17% orthocresol novolak epoxy resin, 8% novolac phenol resin, 74% silica powder, 0.3% curing accelerator, 0.3% ester wax, and 0.4% silane coupling agent. A molding material [C] was produced in the same manner as in Example 1.

Comparative example 2 Ebibis type epoxy resin (epoxy equivalent: 450) 20%
, novolac type phenolic resin 5%, silica powder 74%
, 0.3% curing accelerator, 0.3% ester wax and 0.4% silane coupling agent were mixed, and Example 1
Molding material [D] was produced in the same manner as above.

Using the molding materials [A] to [D] thus produced, 1
A semiconductor sealing device was manufactured in which the semiconductor element was sealed by transfer injection into a mold heated to 70°C and cured. Various characteristics of these semiconductor devices were tested and the results are shown in Table 1. The encapsulating resin composition and semiconductor encapsulating device of the present invention have excellent moisture resistance and soldering heat resistance.
It was possible to confirm the remarkable effects of the present invention.

Table 1 *1 A molded product with a diameter of 50 nn and a thickness of 31111 mm was made by Nidor transfer molding, and this was heated at 127°C12.
The sample was left in saturated steam at 5 atm for 24 hours, and the weight increase was measured.

*2: A molded article similar to that for water absorption was made and post-cured at 175°C for 8 hours to obtain a test piece of an appropriate size, and measured using a thermomechanical analyzer.

*3: Tested according to JIS-6911.

*4: Using a molding material, a silicon chip with two or more aluminum wirings is adhered to a regular 42 alloy frame, transfer molded at 175°C for 2 minutes, and then cured at 175°C for 8 hours. Ta. The thus obtained molded product was previously subjected to a moisture absorption treatment at 40° C., 190% RH for 100 hours, and then immersed in a 250° C. solder bath for 10 seconds. Thereafter, a pressure puller test was conducted in saturated steam at 127"C2.5 atm, and disconnection due to corrosion of aluminum was evaluated as a failure.

*5: 8x8IIIm tummy chip Q-FP (14
x14x1.4mm) package and transfer molded using molding material at 175℃ for 2 minutes,
Post-curing was performed at 175'C for 8 hours.

The semiconductor sealing device manufactured in this way was heated to 85°C.

After 85% moisture absorption treatment for 24 hours, it was immersed in a solder bath at 240''C for 1 minute.The package surface was then observed with a stereomicroscope to evaluate the presence or absence of external resin cracks.

[Effects of the Invention] As is clear from the above description and Table 1, the encapsulating resin composition and semiconductor encapsulating device of the present invention have excellent moisture resistance and soldering heat resistance, are less affected by moisture absorption, and have excellent electrode resistance. It is possible to significantly reduce the occurrence of wire breakage due to corrosion and leakage current due to moisture, and furthermore, it is possible to guarantee reliability over a long period of time.

Claims (1)

[Scope of Claims] 1 (A) Epoxy resin represented by the following general formula, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, m is 0 or an integer of 1 or more, and n is 1 or more. (B) Polyfunctional phenolic resin represented by the following general formula (I) or (II), and ▲Mathematical formulas, chemical formulas, tables, etc.▼...(I) ▲Mathematical formulas, chemical formulas, tables, etc. etc.▼...(II) (However, in the formula, R is C_mH_2_m_+_1, m, n
(represents an integer of 0 or 1 or more) (C) A sealing comprising silica powder as an essential component and containing 50 to 90% by weight of the silica powder of (C) based on the resin composition. Resin composition for use. 2 (A) Epoxy resin represented by the following general formula, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, m represents an integer of 0 or 1 or more, and n represents an integer of 1 or more.) B) Multifunctional phenolic resin represented by the following general formula (I) or (II), and ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...・(II) (However, in the formula, R represents C_mH_2_m_+_1, m, n
(represents an integer of 0 or 1 or more) (C) Semiconductor A semiconductor sealing device characterized by sealing an element.