JPH08239453A - Semiconductor device - Google Patents

Abstract

PURPOSE: To obtain a semiconductor device which is excellent in not only humidity resistance but also corrosion resistance and the plastic package of which is excellent in mechanical properties. CONSTITUTION: This semiconductor device is prepared by sealing a semiconductor element with an epoxy resin composition comprising an epoxy resin, a reaction product of a silane compound having an epoxy group and at least either a methoxy group or an ethoxy group in the molecule and having a molecular weight of 220-278 with a phenolic resin, and an inorganic filler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable semiconductor device.

[0002]

2. Description of the Related Art Semiconductor elements such as transistors, ICs, and LSIs are usually sealed in ceramic packages or plastic packages to form semiconductor devices. The ceramic package itself has heat resistance and excellent moisture permeability, so it is resistant to temperature and humidity, and because of its hollow package, it has high mechanical strength and highly reliable sealing. It is possible. However, since the constituent materials are relatively expensive and have the disadvantage of being inferior in mass productivity, resin sealing using the plastic package has recently become mainstream. As such a resin for semiconductor encapsulation, an epoxy resin composition containing an epoxy resin, a novolak type phenol resin, an inorganic filler as a main component, and further containing a curing accelerator, a coloring agent, and a release agent has been awarded. .

[0003]

However, a semiconductor device sealed with such an epoxy resin composition is easier to seal than a conventional semiconductor device obtained by a hermetic sealing method using a metal or ceramic material. However, the aluminum wiring or aluminum electrodes of the encapsulated semiconductor device corrode due to moisture absorption, and this corrosion causes a disconnection of the aluminum wiring, resulting in defects. Had. This is because water enters the semiconductor device from the interface between the sealing resin and the lead frame or from the surface of the sealing resin, and the immersion water permeates through the sealing resin to remove ionic impurities in the sealing resin. It is believed that the ionic impurities act as carriers and cause corrosion of aluminum wiring or aluminum electrodes.

Therefore, water does not enter the semiconductor device.
Research on the development of semiconductor devices with excellent moisture resistance has been advanced, and those in which a silane coupling agent is contained in a resin composition or those in which an inorganic filler is subjected to a surface treatment have been proposed. The fact is that the effect has not been obtained.

The present invention has been made in view of such circumstances, and is excellent in moisture resistance and thus corrosion resistance.
An object of the present invention is to provide a semiconductor device in which a plastic package itself has excellent mechanical characteristics and the like.

[0006]

In order to achieve the above object, the semiconductor device of the present invention seals a semiconductor element using an epoxy resin composition containing the following components (A) to (C). Take the configuration to stop. (A) Epoxy resin. (B) Molecular weight 2 having an epoxy group in the molecule and at least one of a methoxy group and an ethoxy group
A reaction product of a silane compound of 20 to 278 and a phenol resin. (C) an inorganic filler.

That is, the inventors of the present invention aimed at obtaining a semiconductor device having excellent moisture resistance and, consequently, corrosion resistance. The void at the interface between the inorganic filler particles and the surrounding resin and the interface between the lead frame and the resin are confirmed to be the same, and the inorganic filler particles and the sealing resin for the lead frame are closed in order to close the path. A series of studies were conducted to improve the adhesion. As a result, when a reaction product of a phenolic novolak and a silane compound having an epoxy group in the molecule and having at least one of a methoxy group and an ethoxy group is used as a curing agent for an epoxy resin, the intended purpose is achieved. We found what we gained and arrived at this invention.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described.

The epoxy resin composition used in the present invention is
As described above, the epoxy resin (component A), the reaction product of the phenolic resin with a silane compound having an epoxy group in the molecule and at least one of a methoxy group and an ethoxy group (component B), and an inorganic filler It is obtained using the agent (component C) and is usually in the form of a powder or a tablet thereof.

The epoxy resin serving as the component A is not particularly limited as long as it has two or more epoxy groups in one molecule, and has been conventionally used such as cresol novolak type, phenol novolak type, bisphenol A type and the like. Various epoxy resins used as sealing resins for semiconductor devices can be given. Among these resins, those having a melting point over room temperature and exhibiting a solid state or a high-viscosity solution state at room temperature bring about good results.
As the novolac type epoxy resin, those having an epoxy equivalent of 160 to 250 and a softening point of 50 to 130 ° C. are generally used, and as the cresol novolac type epoxy resin, those having an epoxy equivalent of 180 to 210 and a softening point of 60 to 110 ° C. are generally used. Used.

The reaction product of the silane compound having an epoxy group in the molecule and having at least one of a methoxy group and an ethoxy group of the component B, which is used together with the above-mentioned epoxy resin, and the phenol resin is a cured product of the above-mentioned epoxy resin It acts as an agent and is obtained by reacting any of the following phenolic resins and silane compounds in combination.

Here, phenol novolak, o-cresol novolak, m-cresol novolak, p-cresol novolak, o-ethylphenol novolak, m-ethylphenol novolak, p-ethylphenol novolak, etc. are used as the phenol resin. On the other hand, as silane compounds, 3-glycidoxypropyltrimethoxysilane (MW236),
Glycidoxypropylmethyldimethoxysilane (MW2
20), 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (MW246), 3-glycidoxypropylmethylmethoxyethoxysilane (MW23
4), 3-glycidoxypropyltriethoxysilane (MW278) and the like can be used.

The reaction between the phenol resin and the silane compound can be represented by the following chemical formula (1) when the silane compound is 3-glycidoxypropyltrimethoxysilane, for example.

[0014]

Embedded image

The reaction rate of such a phenol resin and a silane compound is preferably 85% or more, and particularly 9%.
It is preferably 5% or more. Further, the blending ratio of the silane compound to the phenol resin is preferably 0.1 to 10% by weight (hereinafter abbreviated as "%").

As the C component inorganic filler, generally used quartz glass powder, talc, crystalline silica powder,
Alumina powder, clay, calcium carbonate, zirconium oxide, zirconium silicate, beryllium oxide, glass fiber and the like are used as appropriate, but quartz glass powder and crystalline silica powder are particularly preferable.

In the present invention, a curing accelerator, a release agent, and the like can be used, if necessary, in addition to the components A, B, and C. As the curing accelerator, any one that can be used as a catalyst for the curing reaction of the phenol-cured epoxy resin can be used, and examples thereof include 2,4,6-tri (dimethylaminomethyl) phenol and 2-methylimidazole. it can. As the release agent, use may be made of conventionally known long-chain carboxylic acids such as stearic acid and palmitic acid, metal salts of long-chain carboxylic acids such as zinc stearate and calcium stearate, and waxes such as carnauba wax and montan wax. Can be.

The epoxy resin composition used in the present invention comprises:
For example, it can be manufactured as follows. That is, the above components, and optionally other additives such as a pigment and a coupling agent, are appropriately blended, and the blend is melted and mixed in a kneading machine such as a mixing roll machine in a heated state, and cooled to room temperature. Then, the desired epoxy resin composition can be obtained by a series of steps of crushing by known means and tableting if necessary.

The encapsulation of the semiconductor element using such an epoxy resin composition is not particularly limited and can be carried out by a usual method, for example, a known molding method such as transfer molding.

The semiconductor device thus obtained contains a reaction product of a silane compound having an epoxy group in the molecule and at least one of a methoxy group and an ethoxy group and a phenol resin as a curing agent for the epoxy resin. It is sealed with an epoxy resin composition to improve the adhesive state of the resin at the interface between the inorganic filler particles and the resin, the interface between the lead frame and the resin, etc. Therefore, it is extremely excellent in moisture resistance (corrosion resistance). Further, the mechanical strength of the sealed plastic package itself is also excellent.

[0021]

As described above, the semiconductor device of the present invention uses a special epoxy resin composition containing a reaction product of a silane compound having at least one of a methoxy group and an ethoxy group in the molecule and a phenol resin. Since the encapsulating plastic package is different from the one made of the conventional epoxy resin composition, the adhesion state between the resin component and the inorganic filler such as silane powder, the resin component and the lead frame, etc. Has a good adhesion state and blocks the water infiltration route, and has excellent moisture resistance. Therefore,
Corrosion of aluminum wiring and aluminum electrodes does not occur, and reliability is greatly improved. Moreover, the above-mentioned sealed plastic package has excellent mechanical properties and can be widely used not only in semiconductor devices such as transistor elements and integrated circuits, but also in VLSIs (ultra high-density integrated circuits) such as memories and microcomputers. It is.

Next, examples will be described together with comparative examples.

[0023]

Examples 1 to 8 First, a phenol resin was reacted with a silane compound to obtain a curing agent (component B). Next, the above curing agent and other raw materials are mixed, melt-kneaded in a mixing roll machine (roll temperature: 80 to 90 ° C.) for 10 minutes, cooled, solidified, and then pulverized to obtain a desired powdery epoxy resin composition. Was. The composition of each raw material was in accordance with Tables 1 and 2 below.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

Comparative Examples 1 to 4 Instead of the reaction product of the phenol novolac resin and the silane compound, a simple phenol novolac resin was used. Otherwise in the same manner as in Examples 1 to 8, a powdery epoxy resin composition (Comparative Example 1) was obtained.

Further, in place of the reaction product of the phenol novolac resin and the silane compound, 90 parts by weight of the phenol novolac resin and 2 parts by weight of 3-glycidoxylopropyltrimethoxysilane were used as they were without reaction. Otherwise in the same manner as in Examples 1 to 8, a powdery epoxy resin composition (Comparative Example 2) was obtained.

Further, the same amount of gamma-mercaptotriethoxysilane was used in place of 3-glycidoxypropyltriethoxysilane of Example 1. Otherwise, Example 1
A powdery epoxy resin (Comparative Example 3) was obtained in the same manner as.

In place of 3-glycidoxypropyltriethoxysilane of Example 1, silicone oil represented by the following chemical formula (2) having a glycidyl group in the molecule was used. A powdery epoxy resin (Comparative Example 4) was obtained in the same manner as in Example 1 except for the above.

[0030]

Embedded image

Using the powdery epoxy resin compositions obtained in the above Examples and Comparative Examples, semiconductor elements were molded by transfer molding (170 ° C., 2 minutes) to obtain semiconductor devices. With respect to the semiconductor device thus obtained, boiling ρv characteristics, flexural modulus, water absorption, corrosion resistance, etc. were measured. The bending elastic modulus is JIS-K
According to -6911, the water absorption was 50 mm in diameter and 1 mm in thickness for the epoxy resin compositions used in the examples and comparative examples.
After forming into a disc of 40 ° C / 95% RH, 60 ° C /
It was determined by measuring the change in weight by leaving it for 50 hours under the conditions of 95% RH and 80 ° C./95% RH. The corrosion resistance was evaluated by measuring the disconnection time due to corrosion of aluminum wiring or electrodes at 145 ° C., 95% RH, and 4 atm atmosphere.

The results of these measurements are shown in Tables 3 to 5 below.

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Table 5]

From the results shown in Tables 3 to 5, it can be seen that the product of Example has a lower water absorption rate of the plastic package than that of the product of Comparative Example, the corrosion resistance is excellent, and the mechanical properties are excellent. Recognize.

In addition, it is clear from the reaction mechanism of the curing reaction that the silane compound reacts with the phenol resin and is incorporated as a reaction product in the epoxy resin composition which is an example product.

Claims (1)

[Claims] 1. A semiconductor device comprising a semiconductor element encapsulated with an epoxy resin composition containing the following components (A) to (C). (A) Epoxy resin. (B) Molecular weight 2 having an epoxy group in the molecule and at least one of a methoxy group and an ethoxy group
A reaction product of a silane compound of 20 to 278 and a phenol resin. (C) an inorganic filler.