JP2000063487A - Epoxy resin composition and sealed semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellent in humidity resistance and soldering heat resistance by compounding as essential components a specific polyfunctional epoxy resin, a specific polyfunctional phenol resin, a specific amount of an inorganic filler and a curing accelerator. SOLUTION: A polyfunctional epoxy resin of formula I and a polyfunctional phenol resin of formula II are employed. In formula I, R1-R3 are each H, methyl, ethyl, propyl, butyl or t-butyl. In formula II, R is H methyl, ethyl, propyl, butyl or t-butyl; and(n)is 0-10. An inorganic filler is compounded in an amount of 25-93 wt.% based on the composition. As the inorganic filler is preferable silica powder having a low impurity concentration and an average particle size of 30 μm or less. The inorganic filler is compounded preferably in an amount of 50-93 wt.% to attain a mold shrinkage factor of 0.1% or less in particular. The amount of a curing accelerator compounded is preferably 0.01-5 wt.% based on the composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition having excellent moisture resistance and solder heat resistance, and a semiconductor encapsulation device in which a semiconductor chip is encapsulated by the composition.

[0002]

2. Description of the Related Art In recent years, in the field of semiconductor integrated circuits,
At the same time as technology development for high integration and high reliability, automation of the mounting process of semiconductor devices is being promoted. For example, when mounting a flat package type semiconductor device on a circuit board, conventionally, each lead pin has been soldered, but recently, a solder dipping method or a solder reflow method has been adopted.

A conventional semiconductor device sealed with a resin composition comprising an epoxy resin such as a novolac type epoxy resin, a novolac type phenol resin and silica powder has a drawback that the moisture resistance is lowered when the entire device is immersed in a solder bath. was there. Especially when a semiconductor device that has absorbed moisture is immersed, peeling between the encapsulating resin and the semiconductor chip, or the encapsulating resin and the lead frame, and internal resin cracking cause significant moisture resistance deterioration, which may cause wire breakage or moisture due to corrosion of the electrodes. A leak current is generated, and as a result, the semiconductor device has a drawback that it cannot guarantee long-term reliability.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks and has little influence of moisture absorption, and particularly excellent moisture resistance and solder heat resistance after immersion in a solder bath, and a sealing resin. Epoxy resin composition and semiconductor capable of ensuring long-term reliability without peeling between the semiconductor chip or the encapsulating resin and the lead frame and the occurrence of internal resin cracks, and without the occurrence of wire breakage due to electrode corrosion or leak current due to moisture. It is intended to provide a sealing device.

[0005]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above-mentioned object, the present inventor has obtained excellent moisture resistance and solder heat resistance by using a specific epoxy resin and a specific phenol resin. It was found that a resin composition having the above properties can be obtained, and the present invention has been completed.

That is, the present invention is (A) a polyfunctional epoxy resin represented by the following general formula,

[0007]

[Chemical 5] (However, in the formula, R ¹ , R ² and R ³ are a hydrogen atom, a methyl group,
Represents an ethyl group, a propyl group, a butyl group or a t-butyl group) (B) a polyfunctional phenol resin represented by the following general formula,

[0008]

[Chemical 6] (However, in the formula, n is an integer from 0 to 10, and R is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, and
Representing one or a combination of two or more of t-butyl groups) (C) An inorganic filler and (D) a curing accelerator are essential components, and the above-mentioned (C) inorganic filler is added to the resin composition. Epoxy resin composition containing 25 to 93% by weight, and a semiconductor encapsulation device characterized in that a semiconductor chip is encapsulated with a cured product of the epoxy resin composition. Is.

According to another aspect of the present invention, (A) a polyfunctional epoxy resin represented by the following general formula,

[0010]

[Chemical 7] (However, in the formula, R ¹ , R ² and R ³ are a hydrogen atom, a methyl group,
Represents an ethyl group, a propyl group, a butyl group or a t-butyl group) (B) a polyfunctional phenol resin represented by the following general formula,

[0011]

[Chemical 8] (However, in the formula, n is an integer from 0 to 10, and R is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, and
Representing one or a combination of two or more of t-butyl groups) (C) An inorganic filler and (D) a curing accelerator are essential components, and the above-mentioned (C) inorganic filler is added to the resin composition. The epoxy resin composition containing 25 to 93% by weight and having a molding shrinkage ratio of 0.1% or less, and a cured product of the epoxy resin composition for encapsulating a semiconductor chip. The semiconductor encapsulation device is characterized by the following.

The present invention will be described in detail below.

As the epoxy resin (A) used in the present invention, those represented by the above general formulas 5 and 7 are used. As a specific compound, for example,

[0014]

[Chemical 9]

[0015]

[Chemical 10] Etc. Further, as the epoxy resin, one kind or two or more kinds of novolac-based epoxy resin, epibis-based epoxy resin and other generally known epoxy resins can be used together.

As the polyfunctional phenol resin (B) used in the present invention, those represented by the above chemical formulas 6 and 8 are used. As a specific compound, for example,

[0017]

[Chemical 11] (However, in the formula, n represents an integer from 0 to 10)

[0018]

[Chemical 12] (However, in the formula, n represents an integer of 0 to 10.) In addition to the polyfunctional phenol resin, a novolac type phenol obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde. Resin and these modified resins
They can be used alone or in combination of two or more.

As the inorganic filler (C) used in the present invention, those generally used are widely used. Among them, silica powder having a low impurity concentration and an average particle size of 30 μm or less is preferably used. You can If the average particle size exceeds 30 μm, the moisture resistance and moldability are poor, which is not preferable. The content of the inorganic filler is 25 to 93% by weight, preferably 50 to 93% by weight in order to reduce the molding shrinkage to 0.1% or less.
If the proportion is less than 25% by weight, the resin composition has a high hygroscopicity and is inferior in moisture resistance after solder immersion, and if it exceeds 93% by weight, it is inferior in flowability and is inferior in moldability, which is not preferable.

As the curing accelerator (D) used in the present invention, a phosphorus curing accelerator, an imidazole curing accelerator, D
BU-based curing accelerators and other curing accelerators are widely used. These may be used alone or in combination of two or more. The mixing ratio of the curing accelerator is 0.01 with respect to the resin composition.
It is desirable that the compounding amount be 5% by weight. If the proportion is less than 0.01% by weight, the gel time of the resin composition will be long and the curing characteristics will be poor, and if it exceeds 5% by weight, the fluidity will be extremely poor and the moldability will be poor, and the electrical characteristics will also be poor and the moisture resistance will be poor. It is inferior in sex and is not preferable.

The epoxy resin composition of the present invention contains the above-mentioned specific epoxy resin, specific phenolic resin, inorganic filler and curing accelerator as essential components, but is necessary within the range not deviating from the object of the present invention. Depending on, for example, natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, release agents such as paraffins, flame retardants such as antimony trioxide, carbon black,
A colorant such as red iron oxide, a silane coupling agent, a rubber-based or silicone-based low stress imparting agent, and the like can be appropriately added and blended.

As a general method for preparing the epoxy resin composition of the present invention as a molding material, the above-mentioned specific epoxy resin, specific phenol resin, inorganic filler, curing accelerator and other components are prescribed. After blending the raw material components selected in the composition ratio and mixing them sufficiently uniformly with a mixer or the like, melt mixing treatment with a hot roll or mixing treatment with a kneader etc. is further performed, followed by cooling and solidifying, and crushing to an appropriate size. It can be a molding material. When the molding material thus obtained is applied to sealing, coating, insulation, etc. of electronic parts or electric parts such as semiconductor devices, excellent properties and reliability can be imparted.

The semiconductor encapsulation device of the present invention can be easily manufactured by encapsulating a semiconductor chip using the molding material described above. The semiconductor chip to be sealed is not particularly limited to, for example, an integrated circuit, a large scale integrated circuit, a transistor, a thyristor, a diode and the like. The most general method of sealing is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. The molding material is heated and cured at the time of sealing, and finally a semiconductor sealing device sealed with this cured product is obtained. Curing by heating is 150 ° C
It is desirable to heat and cure the above.

[0024]

The epoxy resin composition and semiconductor encapsulation device of the present invention use the above-mentioned specific epoxy resin and specific phenol resin to reduce the water absorption of the resin composition and to improve the thermomechanical properties and low The stress resistance is improved, the occurrence of resin cracks after solder immersion and solder reflow is eliminated, and the deterioration of moisture resistance is reduced.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, “%” means “% by weight”.

Example 1 6.2% of the above-mentioned epoxy resin of chemical formula 9, 4.8% of the above-mentioned chemical resin of chemical formula 11, 4.8% of silica powder, curing accelerator
0.3%, ester wax 0.3% and silane coupling agent 0.4% were mixed at room temperature, further kneaded at 90 to 95 ° C., and cooled and ground to produce a molding material (A).

Example 2 6.6% of the epoxy resin of Chemical formula 9 used in Example 1, Example 1
3.1% of the phenol resin of Chemical formula 11, 1.3% of phenol novolac resin, 88% of silica powder, 0.3% of hardening accelerator
%, Ester wax 0.3%, and silane coupling agent 0.4% were mixed at room temperature, further kneaded at 90 to 95 ° C., and cooled and ground to prepare a molding material (B).

Comparative Example 1 o-Cresol Novolak type epoxy resin 17%, novolac type phenol resin 8%, silica powder 74%, curing accelerator 0.3%, ester wax 0.3% and silane coupling agent 0.4% were mixed, and further mixed. The mixture was kneaded at 90 to 95 ° C., cooled and ground to obtain a molding material (C).

Comparative Example 2 20% of epibis type epoxy resin, 5% of novolac type phenol resin, 74% of silica powder, 0.3% of curing accelerator, 0.3% of ester wax and 0.4% of silane coupling agent were mixed, and further 90 to 95 were mixed. The mixture was kneaded at 0 ° C. and cooled and ground to obtain a molding material (D).

Molding materials (A) to (D) thus produced
Was used to transfer-inject into a mold heated to 175 ° C. and cure to seal a semiconductor chip to manufacture a semiconductor sealing device. Various tests were conducted on these semiconductor encapsulation devices, and the results are shown in Table 1. The epoxy resin composition and the semiconductor encapsulation device of the present invention are excellent in moisture resistance and solder heat resistance. The remarkable effect of the invention could be confirmed.

[0031]

[Table 1] * 1: A molded product with a diameter of 50 mm and a thickness of 3 mm was made by transfer molding, left to stand in saturated steam at 127 ° C and 2.5 atm for 24 hours, and measured by the increased weight. * 2: A molded product similar to that for water absorption was prepared, post-cured at 175 ° C for 8 hours, and a test piece of appropriate size was measured using a thermomechanical analyzer. * 3, * 4: Tested according to JIS-K-6911. * 5: Using a molding material, a silicon chip with two aluminum wirings is bonded to a normal 42 alloy frame, transfer molded at 175 ° C for 2 minutes, and then post-cured at 175 ° C for 8 hours. It was The molded product thus obtained was previously subjected to moisture absorption treatment at 40 ° C., 90% RH for 100 hours, and then immersed in a solder bath at 250 ° C. for 10 seconds. After that, a humidity resistance test was conducted in saturated steam at 127 ° C and 2.5 atm to evaluate the time at which 50% disconnection (defect occurrence) due to aluminum corrosion occurred. * 6: An 8x8mm dummy chip was placed in a QFP (14x14x1.4mm) package, transfer molding was performed for 2 minutes at 175 ° C using the molding material, and post-curing was performed at 175 ° C for 8 hours. . The semiconductor encapsulation device thus manufactured was subjected to moisture absorption treatment at 85 ° C, 85% for 24 hours, and then immersed in a solder bath at 240 ° C for 1 minute. Then, the package surface was observed with a stereoscopic microscope to evaluate the presence or absence of external resin cracks.

[0032]

As is clear from the above description and Table 1, the epoxy resin composition and the semiconductor encapsulation device of the present invention have excellent moisture resistance and solder heat resistance, are less affected by moisture absorption, and are less susceptible to electrode corrosion. It is possible to remarkably reduce the occurrence of leakage current due to disconnection and moisture, and it is possible to guarantee the reliability for a long time.

Front page continued (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 23/29 H01L 23/30 R 23/31 F term (reference) 4J002 CC05X CC07X CD04W CD06W DJ016 EU117 EU207 FD016 FD090 FD130 FD157 FD160 GQ05 4J036 AC02 DC41 DC46 DD07 FA05 FB08 JA07 4M109 AA01 BA01 CA21 EA03 EA06 EB03 EB04 EB06 EB07 EB08 EB09 EB12 EB19 EC01 EC03 EC05

Claims (4)

[Claims] 1. A multifunctional epoxy resin represented by the following general formula (A): (However, in the formula, R ¹ , R ² and R ³ are a hydrogen atom, a methyl group,
Represents an ethyl group, a propyl group, a butyl group or a t-butyl group) (B) a polyfunctional phenol resin represented by the following general formula: (However, in the formula, n is an integer from 0 to 10, and R is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, and
Representing one or a combination of two or more of t-butyl groups) (C) An inorganic filler and (D) a curing accelerator are essential components, and the above-mentioned (C) inorganic filler is added to the resin composition. An epoxy resin composition comprising 25 to 93% by weight. 2. A semiconductor encapsulation device, which is obtained by encapsulating a semiconductor chip with the cured product of the epoxy resin composition according to claim 1. 3. (A) a polyfunctional epoxy resin represented by the following general formula: (However, in the formula, R ¹ , R ² and R ³ are a hydrogen atom, a methyl group,
Represents an ethyl group, a propyl group, a butyl group or a t-butyl group) (B) a polyfunctional phenol resin represented by the following general formula: (However, in the formula, n is an integer from 0 to 10, and R is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, and
Representing one or a combination of two or more of t-butyl groups) (C) An inorganic filler and (D) a curing accelerator are essential components, and the above-mentioned (C) inorganic filler is added to the resin composition. An epoxy resin composition comprising 25 to 93% by weight and having a molding shrinkage of 0.1% or less. 4. A semiconductor encapsulation device, wherein a semiconductor chip is encapsulated with the cured product of the epoxy resin composition according to claim 3.