JPH01206656A - Semiconductor device - Google Patents

Abstract

PURPOSE:To enhance incombustibility and preservation stability in a hightemperature atmosphere by a method wherein a specified hydrotalsite compound is added to an epoxy resin composition containing a brominated epoxy resin. CONSTITUTION:A semiconductor element is sealed in an epoxy resin composition composed of an epoxy resin (component A), phenolic resin (component B), brominated epoxy resin (component C), antimony oxide powder (component D) containing 10ppb or less of U and Th, fused silica powder (component E) containing 10ppb or less of U and Th, and a hydrotalsite compound (component F) represented by a formula I. The component-C brominated epoxy resin should preferably be 420 or more in epoxy equivalence. Halogen ions generated in the thermal decomposition of the brominated epoxy resin employed as a flame retarder are effectively entrapped by the special hydrotalsite compound of the formula I, which ensures high reliability in a high-temperature atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device that maintains excellent reliability even in a high-temperature atmosphere and does not cause memory malfunctions due to radioactive substances.

[Conventional technology]

Semiconductor elements such as transistors, RCs, and LSIs are generally sealed using epoxy resin compositions to form semiconductor devices. The above epoxy resin is characterized by its electrical properties, moisture resistance,
Because it has good adhesive properties, it is used for sealing semiconductor devices and has achieved good results. however,
In recent years, semiconductor devices have come to be used in large quantities in many outdoor equipment such as automobiles, and as semiconductor devices have become larger and have higher output due to higher integration, they have become more heat resistant than ever before. At the same time, many semiconductor devices are now required to have reliability, especially storage reliability at high temperatures, which was not an issue in the past, and at the same time, there is also a need to prevent memory malfunctions caused by radioactive materials. .

(Problems to be Solved by the Invention) Such improvements in heat resistance have conventionally been achieved by increasing the flame retardance of the epoxy resin used for sealing.

That is, by blending a combination of brominated epoxy resin and antimony oxide into an epoxy resin composition, the flame retardance of the cured epoxy resin composition is increased, thereby improving the heat resistance of the sealing resin. There is. The combination of the above-mentioned brominated epoxy resin and antimony oxide shows good results in terms of flame retardancy. However, a problem arises in terms of storage stability at high temperatures. In other words, under high temperature conditions, hydrogen bromide is generated due to thermal decomposition of the brominated epoxy resin, and this hydrogen bromide reacts with the joint between the gold wire and aluminum pad of the semiconductor element, promoting the formation of an alloy. This causes an increase in electrical resistance, resulting in poor continuity.

In addition, with the recent increase in capacity and density of semiconductor memories, the inconvenience of memory malfunctions has arisen due to alpha rays emitted from radioactive substances such as U and Th contained in the sealing resin. ing.

As described above, conventional semiconductor devices have no problems in terms of flame retardancy, but have problems in terms of reliability when left in high temperature conditions, especially when left unused for long periods of time.

There is also the problem of memory malfunctions caused by radioactive substances present in the sealing resin.

This invention was made in view of these circumstances, and its purpose is to provide a semiconductor device that maintains excellent reliability even when left in a high-temperature atmosphere for a long period of time, and that does not cause memory malfunctions due to radioactive substances. do.

[Failure to solve the problem]

In order to achieve the above object, the semiconductor device of the present invention includes:
A configuration is adopted in which a semiconductor element is sealed using an epoxy resin composition containing the following components (A) to (F).

(A) Yuboxiki JJ.

(B) Phenol resin.

(C) Brominated epoxy resin.

(D) Antimony oxide powder having a U and Th content of 10 pph or less.

(E) Fused silica powder having a U and Th content of 10 ppb or less.

(F) A hydrotalcite compound represented by the following formula (1).

MgxAny(Ofl)2x-3y-zz(Co:+)
z・mlzo −・(1) [Operation] That is, the present inventors, in order to achieve the above object,
As a result of a series of studies, we have found that a special hydrotalcin compound represented by the above general formula (1) can effectively remove halogen ions generated during thermal decomposition of brominated epoxy resin as a flame retardant. It was found that reliability under high atmosphere conditions was ensured due to the fact that the Also, memory
This invention was achieved by discovering that malfunctions are caused by radioactive substances in antimony oxide and fused silica, and that if the content is suppressed to 10 ppb or less, memory malfunctions will disappear.

The epoxy resin composition used in this invention includes an epoxy resin (component A), a ferrule resin (component B), a brominated epoxy resin (component C), and tJ.

Antimony oxide powder (D
component), a fused silica powder (component E) having a U and Th content of toppb or less, and a hydrotalcite compound represented by the above general formula (1) (component F). It is usually in powder form or compressed tablet form.

The epoxy resin serving as component A of the above epoxy resin composition is not particularly limited (phenol novolac type epoxy resin, cresol novolac type epoxy resin,
Examples include various epoxy resins that have been used conventionally, such as bisphenol A epoxy resin. These epoxy resins may be used alone or in combination.

Among the above epoxy resins, preferred epoxy resins are novolac type epoxy resins having an epoxy equivalent of 170 to 300, such as phenol novolac type epoxy resins, Talesol novolac type epoxy resins, and the like.

The phenol resin of component B acts as a curing agent for the epoxy resin, and phenol novolak resin, cresol novolac resin, etc. are preferably used. These phenolic resins have a softening point of 50 to 110°
It is preferable that the C1 hydroxyl equivalent is 70 to 150.

When one or both of the above epoxy resins or phenol resins is reacted with an organopolysiloxane represented by the general formula (1) below, crack resistance and temperature cycle resistance can be improved. You will be able to do it. However, it is somewhat disadvantageous in terms of heat resistance. However, by using the above-mentioned F component, the disadvantage of heat resistance is eliminated and excellent heat resistance can be obtained.

As the above-mentioned brominated epoxy resin of component C, it is desirable to use one having an epoxy equivalent of 420 or more, preferably 420 to 550. Particularly good results can be obtained by using a brominated bisphenol type epoxy resin as the brominated epoxy resin. If the epoxy equivalent is less than 420, the heat resistance of the resin tends to be poor (and hydrogen halide gas is also likely to be generated).The amount of brominated epoxy resin used is Resin component of resin composition (A+B10C sufficient component, 1~
It is preferable to set it within the range of 10% by weight (hereinafter abbreviated as "%"). That is, if the amount of brominated epoxy resin used is less than 1%, the effect of improving flammability will be insufficient, whereas if it exceeds 10%, hydrogen halide gas will be generated in large quantities, which tends to have a negative effect on semiconductor devices. This is because it will be done.

The mutual usage ratio of the above-mentioned phenol resin and epoxy resin (including brominated epoxy resin) is appropriately selected from the relationship with the epoxy equivalent of the epoxy resin, but the equivalent ratio of the phenolic hydroxyl group to the epoxy group is 0. 5-1.5
It is preferable to set it within the range of . This is because if the equivalent ratio is out of the above range, the heat resistance of the resulting cured epoxy resin composition tends to decrease.

The antimony oxide powder used as the above component is U.

Th content is 10, ppb or less. Such antimony oxide powder has an average particle size of 0.1
It is preferable to use particles having a maximum particle size of 44 μm or less in the range of 30 μm or less from the viewpoint of increasing the fluidity of the epoxy resin composition and shortening firmness during molding. Further, it is necessary that the U and Th contents are 10 pl)b or less. If it exceeds 10 ppb, it will cause memory malfunction.

The fused silica powder, which is the above component E, also needs to have a U and Th content of 10 ppb or less.

Such materials can be manufactured by various methods known as dry silica manufacturing methods, such as thermal decomposition or hydrolysis of silicon compounds such as silicon tetrachloride, trichlorosilane, methylchlorosilane, and methylmethoxysilane. . In this case, if the above-mentioned compound as a raw material is purified in advance, it is possible to easily produce fused silica powder with a radioactive substance content of 10 ppb or less. In order to improve the fluidity of the epoxy resin composition and shorten firmness during molding, the fused silica powder should contain 5 to 100% spherical silica, and the average particle size of the fused silica should be 1. ~301! m, the maximum particle size is 96μ
It is preferable to set it to m or less. The above spherical silica has an ashesto ratio (major axis/minor axis) of 1 to 1.3.
Preferably.

Such materials are obtained, for example, by melting synthetic or natural quartz powder in a flame with combustible gases such as hydrogen or propane and oxygen gas, or by hydrolyzing tetraethoxysilane or tetramethoxysilane. or by sintering or melting it after hydrolysis.

The F component is a special hydrotalcite compound represented by the general formula (1). This compound captures impurity ions by substituting or coordinating halogen ions and organic acid ions in the epoxy resin composition with its own CO,- ions, and thermally decomposes the brominated epoxy resin. This is thought to have the effect of preventing the generation of hydrogen bromide caused by. The hydrotalzite compound can be divided into many types depending on the ratio of the numbers of x, y, and z in the general formula (1).

Such hydrotalcite compounds may be used alone or in combination of two or more.

From the viewpoint of dispersibility in the epoxy resin composition, such compounds should have an average particle size of 5 μm or less and a maximum particle size of 3 μm.
It is suitable that it is 0 μm or less. The content of such F component is the resin component of the epoxy resin composition (
A+B+C) is preferably set to 0.1 to 5%. That is, if the blending amount is less than 0.1%, the effect of improving high-temperature storage properties will not be sufficiently exhibited, whereas if it exceeds 5%, a phenomenon of deterioration of moisture resistance will be observed.

The epoxy resin composition used in the present invention contains other conventionally used additives in addition to the components A to F, if necessary.

Examples of the other additives include a curing accelerator, a mold release agent, a coloring agent, and a silane coupling agent.

Examples of the curing accelerator include tertiary amines, quaternary ammonium salts, imidazoles, organosun compounds, and boron compounds. These compounds may be used alone or in combination.

As the mold release agent, 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 are used. be able to.

The epoxy resin composition used in this invention can be produced, for example, as follows. That is, the above A-
Ingredient F and other additives described in Section 2 are appropriately blended, this mixture is melt-mixed in a heated state by applying it to a kneading machine such as a mixing roll machine, and after cooling to room temperature, it is pulverized by known means, and the necessary The desired epoxy resin composition can be obtained through a series of steps of tabletting according to the conditions.

The encapsulation of a semiconductor element using such an epoxy resin composition is not particularly limited, and can be performed by a known molding method such as ordinary transfer molding.

The semiconductor device thus obtained has excellent performance in that it maintains reliability when left at high temperatures and can also prevent memory malfunctions.

(Effects of the Invention) As described above, the semiconductor device of the present invention comprises a brominated epoxy resin (component C), an antimony oxide powder (component D) having a U and Th content of 10 ppb or less, and a fused silica powder (component E). ) and a hydrotalcite compound (F component). Because it captures ions, it has excellent reliability even when left at high temperatures.

Furthermore, since the content of radioactive substances is significantly reduced, memory malfunctions will not occur.

Next, examples will be described together with comparative examples.

[Examples 1 to 11, Comparative Examples 1 to 4] First, raw materials as shown in Table 1 below were prepared.

Next, the above raw materials were blended in the proportions shown in Table 2 below, kneaded with a mixing roll machine, cooled and pulverized to obtain the desired powdered epoxy resin composition.

(Hereinafter, blank spaces) The properties of the cured product of the powdered epoxy resin composition obtained as described above were investigated and shown in Table 3 below.

(Left below) In Table 3 above, spiral flow is EMM
I-66 and gel time were measured in accordance with JIS-5966. Linear expansion coefficient and glass transition temperature are TMA
(manufactured by Rigaku Denki Co., Ltd.). Bending elastic modulus 1 Bending strength was measured using a Tensilon universal testing machine (manufactured by Toyo Baldwin). The volume resistivity was measured in accordance with JIS-6911. In addition, to measure element failure in high-temperature conditions, the semiconductor element is sealed with resin and the semiconductor device is assembled.
A total of 20 pieces were exposed to high temperature and evaluated by determining the number of pieces with poor conductivity. The TCT test involves sealing the semiconductor element with resin, assembling the semiconductor device, and heating it at -50'C for 15 minutes to 150°.
Conducted a temperature 4I cycle test of 2000 times of C15 minutes,
The number of ticks produced was measured.

In addition, the α-ray dose can be measured using an α-ray counter (Jumin Chemical Co., Ltd.
! It was measured using

From the results in Table 3, it can be seen that the Example product has higher element reliability when left in a high temperature state than the Comparative Example product, and the amount of alpha radiation that causes memory malfunction is also lower.

Claims (5)

[Claims] (1) A semiconductor device in which a semiconductor element is sealed using an epoxy resin composition containing the following components (A) to (F). (A) Epoxy resin. (B) Phenol resin. (C) Brominated epoxy resin. (D) Antimony oxide powder having a U and Th content of 10 ppb or less. (E) Fused silica powder having a U and Th content of 10 ppb or less. (F) A hydrotalcite compound represented by the following formula (1). MgxAly(OH)_2x_+_3y_-_2z(C
O_3)_2·mH_2O (1) In formula (1), x, y, and z have the relationships of 0<y/x≦1 and 0≦z/y<1.5, respectively, and m represents an integer. (2) The semiconductor device according to claim 1, wherein the fused silica contains 5 to 100% by weight of spherical silica. (3) The semiconductor device according to claim 1 or 2, wherein the fused silica has an average particle size of 1 to 30 μm and a maximum particle size of 96 μm or less. (4) At least one of the epoxy resin or phenol resin has the following general formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼……(1) In formula (1), R is a monovalent organic group. , may be the same or different from each other. However, in one molecule, at least two of the above R are an amino-substituted organic group, an epoxy-substituted organic group, a hydroxyl-substituted organic group, a vinyl-substituted organic group, a mercapto-substituted organic group, and a carboxyl-substituted organic group. A group selected from the group consisting of m
is an integer from 0 to 500. 4. The semiconductor device according to claim 1, wherein the semiconductor device is reacted with an organopolysiloxane represented by: (5) The compound of component (F) above has an average particle size of 5.0 μm
5. The semiconductor device according to claim 1, wherein the maximum particle size is 30 μm or less.