JPH05315473A - Semiconductor device - Google Patents

Abstract

PURPOSE:To manufacture a semiconductor device having excellent bond properties and reliability upon humidity resistance by a method wherein an epoxy resin composition is to contain a reactive product produced by preliminarily reacting an epoxy resin, novolak type phenol resin and a silane compound, etc., represented by a specific structural formula and an inorganic filler. CONSTITUTION:Semiconductor elements such as IC, LSI, etc., are resin-sealed with epoxy resin composition using plastic package, etc., to be formed into a semiconductor device. As for said epoxy resin composition, an epoxy resin composition containing a reactive product produced by preliminarily reacting an epoxy resin, novolak type phenol resin, a silane compound represented by a righthand structural formula and a high grade fatty acid having carbon atoms exceeding 10 and an inorganic filler with one another is to be used. Within said structural formula, X and Y respectively represent a monadic organic group having at least one functional group selected from the groups comprising epoxy radical, amino radical, mercaptan radical and alkoxyl having hydrogen atoms or carbon atoms of 1-4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device which is excellent in adhesiveness with a lead frame and is also excellent in moisture resistance reliability.

[0002]

2. Description of the Related Art Semiconductor elements such as transistors, ICs, and LSIs are usually encapsulated in ceramic packages or plastic packages to form semiconductor devices. Since the ceramic package itself has heat resistance and excellent moisture permeation resistance, the ceramic package is highly resistant to temperature and humidity and can be sealed with high reliability. However, because the constituent materials are relatively expensive,
Due to the drawback of poor mass productivity, resin sealing using the above-mentioned plastic package has recently become the mainstream. An epoxy resin composition has been conventionally used for this type of plastic package material. Since the epoxy resin composition has excellent electrical characteristics, mechanical characteristics, chemical resistance, etc., it has high reliability and is widely used for resin encapsulation of semiconductor devices. As such an epoxy resin composition,
In particular, those which are composed of an o-cresol novolac epoxy resin, a phenol novolac resin as a curing agent, and a curing accelerator such as a tertiary amine and an organic phosphorus compound as an additive, and the like have sealing workability (especially transfer molding). Has been prized for its excellent workability.

[0003]

However, technological innovation in the semiconductor field has been remarkable, and recently, with the increase in integration degree, the device size has become larger and the wiring has become finer, while the package shape has become smaller and thinner. As the shape of the sealing material has been increasing, further improvement in reliability of the sealing material has been demanded. That is, a semiconductor device resin-sealed using a conventional epoxy resin composition,
Among the currently required reliability levels, it is particularly inferior in moisture resistance reliability, and defects mainly occur due to corrosion of aluminum wiring and electrodes on the element. Therefore,
At present, development of an epoxy resin composition for encapsulation, which has excellent moisture resistance reliability and good adhesiveness, is desired.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a semiconductor device having excellent adhesiveness to a lead frame and excellent moisture resistance reliability.

[0005]

In order to achieve the above object, the semiconductor device of the present invention seals a semiconductor element with an epoxy resin composition containing the following components (A) to (C). Take the configuration. (A) Epoxy resin. (B) A reaction product obtained by preliminarily reacting a novolac type phenol resin, a silane compound represented by the following general formula (1), and a higher fatty acid having 10 or more carbon atoms.

[Chemical 3] (C) Inorganic filler.

[0006]

That is, the present inventors have conducted a series of studies in order to obtain a sealing resin having excellent adhesion to a lead frame and moisture resistance. As a result, if a special reaction product obtained by pre-reacting a novolac-type phenol resin, a specific silane compound, and a higher fatty acid is used as a curing agent for the epoxy resin, excellent adhesion to the lead frame is obtained, As a result, they have found that the intrusion of water into the interface between the lead frame and the sealing resin is suppressed, and that a highly reliable one can be obtained even when used in a high temperature and high humidity atmosphere, and reached the present invention.

The epoxy resin composition used in the present invention comprises an epoxy resin (component A), a reaction product (component B) obtained by pre-reacting a specific component, and an inorganic filler (component C). Is obtained by using
Usually, it is in the form of powder or a tablet obtained by compressing it.

The above epoxy resin (component A) is 1
Examples of the epoxy resin having two or more epoxy groups in the molecule include cresol novolac type epoxy resin, phenol novolac type epoxy resin, bisphenol A type epoxy resin, and biphenyl type epoxy resin. These may be used alone or in combination. Among such epoxy resins, the epoxy equivalent is 1
Those having a softening point of 50 to 130 ° C. and a softening point of 00 to 300 are preferably used. Further, for these epoxy resins, it is preferable that the content of ionic impurities and hydrolyzable ions is small, and specifically, the concentration of free sodium ions,
It is preferable to use one having a chlorine ion concentration of 5 ppm or less and a hydrolyzable ion concentration of 600 ppm or less.

The reaction product (component B) acts as a curing agent for the epoxy resin (component A) and comprises a novolac type phenol resin and a silane compound represented by the following general formula (1). And a higher fatty acid having 10 or more carbon atoms are preliminarily reacted.

[0010]

[Chemical 4]

That is, the above reaction product (component B) is
Organic group (X portion), hydroxyl group or alkoxy group (Y portion) of the specific silane compound represented by the general formula (1)
And a hydroxyl group in the novolac type phenolic resin and a carboxyl group in the higher fatty acid react with each other. Reaction product (component C) thus obtained
Has a softening point of 60 to 100 ° C. and a melt viscosity of 3 to 30 poise (according to a 150 ° C. cone plate method).

The novolac type phenol resin usually acts as a curing agent for the epoxy resin (component A), and examples thereof include phenol novolac resin and cresol novolac resin. As such novolac type phenolic resin, it is preferable to use one having a softening point of 50 to 110 ° C. and a hydroxyl group equivalent of 70 to 150. In addition to the production of the reaction product (component B), the above novolac type phenol resin may be used alone. The compounding ratio of the novolac type phenol resin (including the novolac type phenol resin in the reaction product) is such that the hydroxyl group in the novolac type phenol resin is 0.1% per equivalent of the epoxy group in the epoxy resin (component A). It is preferable to set it so as to be 5 to 2.0 equivalents. It is more preferably 0.8 to 1.2 equivalents.

As the silane compound represented by the above general formula (1), a silane coupling agent can be used,
Specifically, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N, N -Bis [(methyldimethoxysilyl) propyl] amine, N, N-bis [3- (methyldimethoxysilyl) propyl] ethylenediamine, N, N-bis [3- (trimethoxysilyl) propyl] amine, N, N- Bis [3- (trimethoxysilyl) propyl] ethylenediamine, 3- (N,
N-diglycidyl) aminopropyltrimethoxysilane, N-glycidyl-N, N-bis [3- (methyldimethoxysilyl) propyl] amine, N-glycidyl-
N, N-bis [3- (trimethoxysilyl) propyl]
Amine, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane,
3-mercaptotrimethoxysilane, 3-mercaptopropyltrimethoxysilane, N-[(3-trimethoxysilyl) propyl] diethylenetriamine, N-[(3
-Trimethoxysilyl) propyl] triethylenetetraamine, N-3-trimethoxysilylpropyl-m-phenylenediamine and the like. These may be used alone or in combination.

Examples of the higher fatty acid having 10 or more carbon atoms include palmitic acid, stearic acid, oleic acid, arachidic acid and behenic acid, which may be used alone or in combination.

The reaction product (component B) is obtained, for example, as follows. That is, the novolac type phenolic resin, the silane compound represented by the general formula (1), and a specific higher fatty acid are appropriately mixed in a reaction vessel equipped with a stirrer, and the temperature is 130 to 180 ° C., particularly preferably 130 to 1
The reaction is carried out at 50 ° C for 2 to 5 hours. Then, the low boiling point component obtained by this reaction is removed from the system by degassing under the condition of 130 to 150 ° C. In the production of this reaction product (component B), the above-mentioned respective blends are blended in an appropriate blending ratio, but the novolac type phenol resin is used in a large excess.

The amount of the reaction product (component B) blended is such that the total amount of the silane compound component and the higher fatty acid component in the reaction product (component B) is 0.05 based on the total amount of the epoxy resin composition.
It is preferable to set in the range of 1.0 wt% (hereinafter abbreviated as “%”). That is, if it is less than 0.05%, the adhesiveness to the lead frame deteriorates, and conversely, if it exceeds 1.0%, the curability of the epoxy resin composition tends to deteriorate.

The above-mentioned inorganic filler (component C) is not particularly limited and conventionally known ones can be used. For example, not only crystalline and fusible silica but also aluminum oxide, beryllium oxide, silicon carbide,
Examples include silicon nitride. The blending amount of the inorganic filler (C component) is 60 to 90 based on the whole epoxy resin composition.
It is preferable to set in the range of%.

In the epoxy resin composition used in the present invention, a curing accelerator, a flame retardant, a release agent, a pigment and the like are appropriately blended in addition to the components A to C as required.

Examples of the curing accelerator include imidazoles, tertiary amines, organic phosphorus compounds, aluminum compounds, titanium compounds and the like.

As the above flame retardant, compounds such as novolac type brominated epoxy resin, bis A type brominated epoxy resin, antimony trioxide and antimony pentoxide can be appropriately used alone or in combination.

Examples of the releasing agent include higher fatty acids, higher fatty acid esters, higher fatty acid calcium compounds, etc., which may be used alone or in combination.

The epoxy resin composition used in the present invention may be blended with a silicone oil and a rubber component such as a silicone rubber or a synthetic rubber in order to reduce the stress in addition to the above-mentioned other additives, and the moisture resistance reliability may be improved. For the purpose of improving the reliability in the property test, an ion trap agent such as hydrotalcite may be added.

The epoxy resin composition used in the present invention can be manufactured, for example, as follows. That is, first, the novolac type phenol resin, the silane compound represented by the general formula (1), and a higher fatty acid having 10 or more carbon atoms are preliminarily reacted according to the above conditions to prepare a reaction product (component B). .. Next, this reaction product (component B), epoxy resin (component A), inorganic filler (component C) and, if necessary, other additives, and optionally also a novolac type phenol resin as a curing agent. Are blended in appropriate proportions and premixed. Then, the mixture is put into a kneading machine such as a mixing roll machine and kneaded in a heated state to be melt-mixed. Then, it can be manufactured by a series of steps in which it is cooled to room temperature, pulverized by a known means, and tableted 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 known molding method such as ordinary transfer molding.

The semiconductor device thus obtained has excellent adhesion to the lead frame due to the action of the special reaction product (component B) obtained by the preliminary reaction, and the interface between the lead frame and the sealing resin. Infiltration of water into the body is suppressed.

[0026]

As described above, the semiconductor device of the present invention is resin-sealed with the epoxy resin composition containing the special reaction product (component B). Therefore, it has excellent adhesiveness with the lead frame, suppresses the infiltration of water into the interface between the lead frame and the sealing resin, and has excellent moisture resistance reliability, so it can be used in a high temperature and high humidity atmosphere. However, it has high reliability. Therefore, the semiconductor device of the present invention has a high reliability in which the problem occurrence rate is significantly reduced as compared with the conventional device even when used under severe conditions.

Next, examples will be described together with comparative examples.

First, prior to the Examples, the reaction product (B
Ingredients) were produced according to the following production method.

[Production Method of Reaction Product] Each component shown in the following Table 1 was blended in the ratio shown in the same table, charged into a reaction vessel equipped with a stirrer, and preliminarily reacted under the reaction conditions shown in the same table. Then, four kinds of reaction products were produced by degassing (150 ° C.).

[0030]

[Table 1] * 1: Hydroxyl equivalent 105, softening point 83 ° C. * 2: γ-glycidoxypropyltrimethoxysilane. * 3: 3-aminopropyltrimethoxysilane.

[0031]

Examples 1 to 6 and Comparative Examples The above reaction products a to d, the epoxy resin shown in Table 2 below, the inorganic filler and the other additives were blended in the ratio shown in the same table, and the mixture was mixed with a mixing roll machine to obtain 100. The mixture was kneaded at 5 ° C. for 5 minutes to obtain a sheet-shaped composition. Then, the obtained sheet-shaped composition was pulverized to obtain a target powdery epoxy resin composition.

[0032]

[Table 2]

Using the powdery epoxy resin compositions of the examples and comparative examples thus obtained, a humidity resistance test device was sealed to evaluate the moisture resistance reliability, and a semiconductor device was obtained. A pressure cooker test (121 ° C. × 2 atm × 100% RH) was performed using the obtained semiconductor device, and the number of defective conduction (in 100) was determined after 300 hours. The results are shown in Table 3 below.

In order to measure the adhesive force with the lead frame, as shown in FIGS. 1A and 1B, a metal plate 1 made of the same material as the lead frame (alloy-42 or copper) is used. , Upper surface diameter a = 9 mm, lower surface diameter b = 1
A truncated cone-shaped cured product 2 having a height of 1 mm and a height h = 10 mm was prepared, and the shear adhesive force between the truncated cone-shaped cured product 2 and the metal plate 1 was measured. The results are also shown in Table 3 below.

[0035]

[Table 3]

From the results shown in Table 3 above, each of the example products has a high adhesive force, and the number of defects is extremely smaller than that of the comparative example product. From this, it can be seen that the example product has high adhesiveness to the lead frame and excellent moisture resistance reliability.

[Brief description of drawings]

1A and 1B are explanatory diagrams showing a method for measuring a shear adhesive force between a metal plate and a cured product of an epoxy resin composition.

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Claims (2)

[Claims] 1. A semiconductor device obtained by encapsulating a semiconductor element with an epoxy resin composition containing the following components (A) to (C). (A) Epoxy resin. (B) A reaction product obtained by preliminarily reacting a novolac type phenol resin, a silane compound represented by the following general formula (1), and a higher fatty acid having 10 or more carbon atoms. [Chemical 1] (C) Inorganic filler. 2. An epoxy resin composition for semiconductor encapsulation containing the following components (A) to (C). (A) Epoxy resin. (B) A reaction product obtained by preliminarily reacting a novolac type phenol resin, a silane compound represented by the following general formula (1), and a higher fatty acid having 10 or more carbon atoms. [Chemical 2] (C) Inorganic filler.