JP2000248154A - Epoxy resin composition and semiconductor sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition improved in impurity characteristics and moisture resistance and excellent in moldability and reflow crack resistance by blending an o-cresol novolak epoxy resin, a specified combination of curing agents comprising phenolic resins, a specified combination of cure accelerators, and an inorganic filler as the essential constituents. SOLUTION: The composition contains an o-cresol novolak epoxy resin represented by formula I (wherein (n) is 0 or an integer of greater than 1); curing agents comprising phenolic resins, containing a dicyclopentadiene type phenolic resin (A) represented by formula II (wherein (n) is 0, or greater than 1) and a novolak phenolic resin (B) represented by formula III (wherein (n) is 0, or greater than 1) at a weight ratio of resin A to resin B of (0.2 to 10):1; a cure accelerator containing 1,2-trimethylenebenzimidazole (C) represented by formula IV and triphenylphosphine (D) represented by formual V at a weight ratio of compound C to compound D of (0.2 to 10):1; and an inorganic filler in an amount of 25-95 wt.% based on the total composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition and a semiconductor encapsulation device having excellent reliability such as moldability and reflow crack resistance in a semiconductor package.

[0002]

2. Description of the Related Art Conventionally, as a semiconductor encapsulating material, a method of curing an o-cresol novolak type epoxy resin with a novolak type phenol resin is often used. However, in recent years, in the field of semiconductor integrated circuits, while the size of chips has been increased due to higher integration, packages have become thinner, and higher reflow crack resistance has been required.

On the other hand, triphenylphosphine (TPP), 1,8-diazabicyclo [5,
[4,0] undecene-1 (DBU), imidazoles, and the like have been used, but since they each exhibit unique curability, they could not satisfy all the properties required for the sealing resin. Above all, imidazoles promote the reaction under relatively low temperature conditions and provide excellent heat resistance and curability, so in terms of moldability and reflow crack resistance,
It is superior to other curing accelerators. But,
Impurity characteristics and moisture resistance reliability were significantly inferior to other curing accelerators.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and has improved impurity characteristics and moisture resistance, excellent moldability and reflow crack resistance, and has a sealing resin and a semiconductor. There is no peeling between the chip or the sealing resin and the lead frame, and no occurrence of internal resin cracks.
An object of the present invention is to provide an epoxy resin composition and a semiconductor encapsulation device that can guarantee long-term reliability.

[0005]

Means for Solving the Problems As a result of diligent studies to achieve the above object, the present inventor has used dicyclopentadiene type phenol resin and novolak type phenol resin in combination as phenol resin curing agents, and The inventors have found that the above objects can be achieved by using 1,2-trimethylenebenzimidazole and triphenylphosphine in combination as curing accelerators, and have completed the present invention.

That is, the present invention provides (A) an o-cresol novolak type epoxy resin represented by the following general formula:

Embedded image (Where n represents an integer of 0 or 1 or more). (B) (a) a dicyclopentadiene-type phenol resin represented by the following general formula:

Embedded image (Where n represents 0 or an integer of 1 or more) (b) Novolak-type phenol resin represented by the following general formula

Embedded image (Where n represents an integer of 0 or 1 or more) and a phenolic resin curing agent containing (a) component / (b) component in a weight ratio of 0.2 to 10; c) 1,2-trimethylenebenzimidazole represented by the following general formula:

Embedded image (D) triphenylphosphine represented by the following general formula

Embedded image And a curing accelerator containing (c) component / (d) component in a ratio of 0.2 to 10 in weight ratio and (D) an inorganic filler as essential components. (D) An epoxy resin composition comprising an inorganic filler in a proportion of 25 to 95% by weight. A semiconductor sealing device is characterized in that a semiconductor chip is sealed with a cured product of the epoxy resin composition.

Hereinafter, the present invention will be described in detail.

As the (A) o-cresol novolak type epoxy resin used in the present invention, an epoxy resin represented by the general formula 6 is used.

As the phenol resin curing agent (B) used in the present invention, (a) a dicyclopentadiene type phenol resin represented by the general formula (7) and (b) a novolak type phenol resin represented by the general formula (8) are used in combination. Is what you do.
The dicyclopentadiene-type phenol resin (a) and the novolak-type phenol resin (b) have a weight ratio of the component (a) / component (b) of 0.2 to 10, preferably 0.5 to 5. Use in proportions. If the weight ratio is less than 0.2, the moisture absorption resistance is reduced, and if it exceeds 10, the molding workability is reduced. Therefore, it is better to limit to the above range.

In the present invention, the mixing ratio of (B) the phenolic resin curing agent is such that [(A) the epoxy group of the epoxy resin / (B) the phenolic hydroxyl group of the phenolic resin] has an equivalent ratio of 0.1 to 10; , Preferably 0.5 to 2.
Use in the range of 0. Equivalent ratio is less than 0.1 or 10
If it exceeds 300, the curability, heat resistance, moisture resistance, molding workability, and electrical properties of the cured product will be poor, and any case is not preferable. Therefore, it is better to limit to the above range.

The (C) curing accelerator used in the present invention comprises (c) 1,2-trimethylenebenzimidazole represented by the above general formula (9) and (d) triphenyl represented by the above general formula (10). It is a combination of phosphine.
(C) 1,2-trimethylenebenzimidazole and (d) triphenylphosphine are in a weight ratio of [(c)
Component / (d) component] is 0.1 to 10, preferably 0.5.
Use at a rate of ~ 5. If the weight ratio is less than 0.1,
(C) The effect of 1,2-trimethylenebenzimidazole is not exhibited, and if it exceeds 10, the workability of molding decreases. Therefore, it is better to limit to the above range.

The mixing ratio of the curing accelerator (C) in the present invention is 0.01 to 5.0 based on the whole resin composition.
It is desirable to contain it in the range of weight%. If this ratio is less than 0.01, it will not function as a curing agent and will not function as a curing agent.
If the content is more than 10% by weight, the curing of the sealing resin is too fast, which is not suitable for practical use and is not preferred.

The inorganic filler (D) used in the present invention has a low impurity concentration, a maximum particle size of 100 μm or less,
An inorganic filler having an average particle size of 30 μm or less is preferably used. If the average particle size exceeds 30 μm, the moisture resistance and the moldability are poor, which is not preferable. Specific examples of the inorganic filler include, for example, silica powder, silicon nitride powder, alumina powder, aluminum nitride, antimony trioxide, antimony pentoxide, antimony pentoxide, talc, calcium carbonate, titanium white, clay, mica, Bengala, glass fiber and the like can be mentioned, and these can be used alone or in combination of two or more. Among these, silica powder and alumina powder are particularly preferable and are often used. The mixing ratio of the inorganic filler is 2 to the entire resin composition.
Desirably, the content is 5 to 95% by weight. If the proportion is less than 25% by weight, heat resistance, moisture resistance, solder heat resistance, mechanical properties and moldability deteriorate, and if it exceeds 95% by weight, burrs become large and the moldability is poor and not suitable for practical use.

The epoxy resin composition of the present invention comprises the aforementioned o-cresol novolak type epoxy resin, dicyclopentadiene type phenol resin, novolak type phenol resin, 1,2-trimethylenebenzimidazole, triphenylphosphine and an inorganic filler. Is an essential component, but as far as it does not violate the purpose of the present invention, and if necessary, for example, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, paraffins, etc. Release agents, flame retardants such as chlorinated paraffin, brominated toluene, and hexabromobenzene, low-stress components such as elastomers, coloring agents such as carbon black and red iron, coupling agents such as silane, and silicone oil It can be added and blended.

The general method for preparing the epoxy resin composition of the present invention as a molding material is as follows: o-cresol novolak type epoxy resin, dicyclopentadiene type phenol resin, novolak type phenol resin,
Blending 2-trimethylenebenzimidazole, triphenylphosphine, inorganic filler and other ingredients,
After sufficiently mixing by a mixer or the like, a melt-mixing process using a hot roll or a mixing process using a kneader or the like is performed, and then the mixture is solidified by cooling and pulverized to an appropriate size to obtain a molding material. If the molding material thus obtained is applied to sealing, coating, insulating, etc. of electronic parts or electric parts such as semiconductor devices, excellent properties and reliability can be imparted.

Further, the semiconductor sealing device of the present invention can be easily manufactured by sealing 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 common sealing method is a low pressure transfer molding method, but sealing by injection molding, compression molding, casting, or the like is also possible. After sealing with a molding material, it is heated and cured, and finally a semiconductor sealing device sealed with a cured product of this composition is obtained. Curing by heating is 1
It is desirable to cure by heating to 50 ° C. or higher.

[0017]

The epoxy resin composition and the semiconductor encapsulation device of the present invention use a specific combination of a phenolic resin curing agent and a specific combination of a curing accelerator to reduce impurities in the resin composition and reduce the amount of impurities in the semiconductor package. In the above, the reliability of the moisture resistance was able to be improved.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described specifically 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 16% of an o-cresol novolak type epoxy resin represented by the above formula 6, and a phenol resin 4.5 represented by the above formula 7
%, Phenol resin 4.5% shown in Chemical formula 8, 0.15% curing accelerator shown in Chemical formula 9, 0.15% curing accelerator shown in Chemical formula 10, 74% fused silica powder, silane 0.4% of a coupling agent and 0.3% of an ester wax are blended and mixed at room temperature, and further mixed at 90 to 95 ° C.
After kneading and cooling, the mixture was pulverized to produce a molding material. This molding material was transfer-injected into a mold heated to 175 ° C. and cured to form a molded product. The molded article was tested for impurity concentration and moisture resistance, and the results are shown in Table 1. The remarkable effect of the present invention was confirmed.

Comparative Example 1 16% of o-cresol novolak epoxy resin shown in Chemical formula 6, 9% of phenol resin shown in Chemical formula 8, 0.15% of curing accelerator shown in Chemical formula 9, and 0.15% of the indicated hardening accelerator, 74% of fused silica powder, 0.4% of silane coupling agent and 0.3% of ester waxes were blended, mixed at room temperature, and further 90-95 ° C.
After kneading and cooling, the mixture was pulverized to produce a molding material. This molding material was transfer-injected into a mold heated to 175 ° C. and cured to form a molded product. The molded article was tested for impurity concentration and moisture resistance, and the results are shown in Table 1.

Comparative Example 2 16% of an o-cresol novolak type epoxy resin represented by the above formula 6, and a phenol resin 4.5 represented by the above formula 7
%, 4.5% of the phenolic resin shown in Chemical formula 8, 0.3% of the curing accelerator shown in Chemical formula 10, and fused silica powder 74
%, A silane coupling agent 0.4% and an ester wax 0.3%, and mixed at room temperature.
After kneading and cooling at ~ 95 ° C, the mixture was pulverized to produce a molding material. This molding material was transfer-injected into a mold heated to 175 ° C. and cured to form a molded product. The molded article was tested for impurity concentration and moisture resistance, and the results are shown in Table 1.

Comparative Example 3 16% of the o-cresol novolak type epoxy resin shown in the above formula 6, 9% of the phenol resin shown in the above formula 8, 0.3% of a curing accelerator shown in the above formula 10, and fused silica powder 74%, 0.4% of a silane coupling agent and 0.3% of an ester wax were blended, mixed at room temperature, kneaded and cooled at 90 to 95 ° C, and then pulverized to produce a molding material. This molding material was transfer-injected into a mold heated to 175 ° C. and cured to form a molded product. Since this molded article was tested for impurity concentration and moisture resistance,
The results are shown in Table 1.

[0023]

[Table 1] * 1: A molded product was prepared by transfer molding, and after post-curing at 175 ° C. for 8 hours,
Extraction with hot water was performed at 80 ° C. for 2 hours, and measurement was performed by ion chromatography.

* 2: A molded article was prepared by transfer molding, post-cured at 175 ° C. for 8 hours, and measured by a thermomechanical analyzer.

* 3: Using a molding material, a silicon chip (test element) having two or more aluminum wirings was bonded to a frame, transfer molded at 175 ° C. for 2 minutes, and QFP-208P, 2.8 mmt And a post-curing was carried out at 175 ° C. for 8 hours. The molded article thus obtained was previously subjected to 85 ° C., 40% RH, 168
After the moisture absorption treatment for a time, the mixture was passed through an IR reflow furnace at Max 240 ° C. four times. Thereafter, PCT is performed in saturated steam at 127 ° C. and 2.5 atm.
The time at which 0% disconnection (occurrence of a defect) occurred was evaluated.

[0026]

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 impurity characteristics, do not peel off even after IR reflow, and have excellent moisture resistance. As a result, disconnection due to electrode corrosion and occurrence of leak current due to moisture can be significantly reduced, and reliability can be guaranteed for a long period of time.

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Claims (2)

[Claims] (A) an o-cresol novolak type epoxy resin represented by the following general formula: (Where n represents 0 or an integer of 1 or more) (B) (a) a dicyclopentadiene-type phenol resin represented by the following general formula: (Where n represents 0 or an integer of 1 or more) (b) Novolak-type phenol resin represented by the following general formula: (Where n represents an integer of 0 or 1 or more) and a phenolic resin curing agent containing (a) component / (b) component in a weight ratio of 0.2 to 10; c) 1,2-trimethylenebenzimidazole represented by the following general formula: (D) triphenylphosphine represented by the following general formula: And a curing accelerator containing (c) component / (d) component in a ratio of 0.2 to 10 in weight ratio and (D) an inorganic filler as essential components. (D) An epoxy resin composition comprising an inorganic filler in a proportion of 25 to 95% by weight. 2. A semiconductor sealing device, wherein a semiconductor chip is sealed with a cured product of the epoxy resin composition according to claim 1.