JP3014970B2 - Epoxy resin composition for semiconductor encapsulation - Google Patents

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 for semiconductor encapsulation capable of producing a semiconductor device which maintains excellent reliability even in a high-temperature atmosphere and does not cause a memory malfunction due to a radioactive substance. Things.

[0002]

2. Description of the Related Art Semiconductor devices such as transistors, ICs, and LSIs are generally sealed with an epoxy resin composition to form semiconductor devices. The epoxy resin has been used for encapsulation of a semiconductor device because of its good electrical properties, moisture resistance, adhesiveness and the like, and has achieved good results.
However, in recent years, semiconductor devices have been used in large quantities in many outdoor devices such as automobiles,
In addition, as semiconductor devices become larger and more integrated, and higher power is required, higher heat resistance, especially high-temperature storage reliability, which was not a problem in the past, is required for many semiconductor devices. At the same time, there is an increasing demand for prevention of memory malfunction caused by radioactive materials.

[0003]

The improvement of the heat resistance has been conventionally performed by increasing the flame retardancy of an epoxy resin used for sealing. That is, by combining the brominated epoxy resin and antimony oxide into the epoxy resin composition, the flame retardancy of the cured epoxy resin composition is increased, thereby improving the heat resistance of the sealing resin. I have. The combination of the above brominated epoxy resin and antimony oxide shows good results in terms of flame retardancy. However, there is a problem in terms of storage stability at high temperatures. In other words, in a high temperature state, hydrogen bromide is generated by the thermal decomposition of the brominated epoxy resin, and the hydrogen bromide reacts with the bonding portion between the gold wire of the semiconductor element and the aluminum pad to promote the formation of an alloy. This causes an increase in the electric resistance value, resulting in poor conduction. In addition, with the recent increase in capacity and density of semiconductor memory, the inconvenience that the memory may malfunction due to α-rays emitted from radioactive substances such as U and Th contained in the sealing resin has arisen. I have.

As described above, the conventional semiconductor device has no problem in terms of flame retardancy, but has a problem in terms of reliability when left in a high temperature state, particularly when left for a long time. In addition, there is a problem that a memory malfunctions due to a radioactive substance present in the sealing resin.

The present invention has been made in view of such circumstances, and provides a semiconductor device which maintains excellent reliability even when left in a high-temperature atmosphere for a long time and does not cause a malfunction of a memory due to a radioactive substance. It is an object of the present invention to provide an epoxy resin composition for semiconductor encapsulation that can be used.

[0006]

Means for Solving the Problems To achieve the above object, the epoxy resin composition for semiconductor encapsulation of the present invention comprises the following components (A) to (F). (A) Epoxy resin. (B) a phenolic resin. (C) Brominated epoxy resin. (D) The content of U and Th is 10 ppb or less , and the average particle size is
In 0.1 to 30 [mu] m, antimony oxide powder outermost large diameter following 44 .mu.m. (E) A fused silica powder having a U and Th content of 10 ppb or less. (F) hydrotalcite analogue compound.

Namely, the present inventors have found that in order to achieve the above object, the results of extensive series of studies, the halogen ions generated during thermal decomposition of the brominated epoxy resin as a flame retardant, c Idorotaru It has been found that since the site compounds are effectively trapped, reliability under a high atmosphere is ensured. In addition, the present inventors have found that the cause of the malfunction of the memory is caused by radioactive substances in antimony oxide or fused silica, and that when the content is suppressed to 10 ppb or less, the malfunction of the memory disappears, and the present invention has been reached.

[0008]

Next, the present invention will be described in detail.

An epoxy resin composition for encapsulating a semiconductor according to the present invention comprises an epoxy resin (component A), a phenol resin (component B), a brominated epoxy resin (component C), and a content of U and Th of 10 ppb or less. With an average particle size of 0.1 to 30 μm
In using a maximum particle size antimony oxide powder 44 .mu.m (D component), U, and the following fused silica powder Th content 10 ppb (E component), hydrotalcite analogue compound and (F component) obtained And is usually in the form of a powder or a tablet thereof.

[0010] A of the epoxy resin composition for semiconductor encapsulation described above
The epoxy resin used as a component is not particularly limited, and various epoxy resins conventionally used, such as a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, and a bisphenol A type epoxy resin, can be used. These epoxy resins may be used alone or in combination.

Among the above epoxy resins, preferred epoxy resins are novolak epoxy resins having an epoxy equivalent of 170 to 300, such as phenol novolak epoxy resins and cresol novolak epoxy resins.

The component B phenol resin functions as a curing agent for the epoxy resin, and phenol novolak resins, cresol novolak resins, and the like are preferably used. These phenolic resins have a softening point of 5
The temperature is preferably 0 to 110 ° C and the hydroxyl equivalent is 70 to 150.

When one or both of the above epoxy resins or phenolic resins are reacted with an organopolysiloxane represented by the following general formula (2), the effect of improving crack resistance and temperature cycle resistance is obtained. Will be able to And, by using the F component, excellent heat resistance can be obtained.

[0014]

Embedded image

As the brominated epoxy resin of the component C, those having an epoxy equivalent of 420 or more, preferably 420
It is desirable to use those of ~ 550. In particular, the use of a brominated bisphenol-type epoxy resin as the above-mentioned brominated epoxy resin gives good results. If the epoxy equivalent is less than 420, not only does the resin have a tendency to be inferior in heat resistance, but also a hydrogen halide gas is easily generated. The amount of the brominated epoxy resin used is determined by the resin component (A + B + C) of the epoxy resin composition.
Component), it is preferable to set within the range of 1 to 10% by weight (hereinafter abbreviated as "%"). That is, if the amount of the brominated epoxy resin is less than 1%, the effect of improving the flame retardancy becomes insufficient, and if it exceeds 10%, the generation of hydrogen halide gas tends to increase, which tends to adversely affect the semiconductor element. Because it can be done.

The mutual use ratio of the phenol resin and the epoxy resin (including the brominated epoxy resin) is appropriately selected depending on the relationship with the epoxy equivalent of the epoxy resin. The equivalent ratio of the phenolic hydroxyl group to the epoxy group is used. Is preferably set in the range of 0.5 to 1.5. If the equivalent ratio is out of the above range, the heat resistance of the cured epoxy resin composition obtained tends to decrease.

The antimony oxide powder as the component D is as follows:
U and Th content must be 10 ppb or less.
You. That is, if it exceeds 10 ppb, it causes a malfunction of the memory . Also like this
Antimony oxide powder improves the fluidity of the epoxy resin composition.
From the viewpoint of increasing the height and shortening the burr during molding
The average particle size is 0.1-30 μm and the maximum particle size is 44
It is necessary to use one having a size of μm or less.

The fused silica powder as the component E is also U,
Th content needs to be 10 ppb or less.
Such a compound can be produced by various methods known as a method for producing fumed silica, for example, thermal decomposition or hydrolysis of silicon compounds such as silicon tetrachloride, trichlorosilane, methylchlorosilane, and methylmethoxysilane. In this case, if the compound as a raw material is purified in advance, a fused silica powder in which the radioactive substance is reduced to 10 ppb or less can be easily produced. In such a fused silica powder, in order to increase the fluidity of the epoxy resin composition and to reduce burrs during molding, spherical silica is contained in an amount of 5 to 100%, and the average particle diameter of the fused silica is 1 to 1. ~ 30μm, maximum particle size is 96μ
m or less. The spherical silica has an aspect ratio (major axis / minor axis) of 1 to 1.3.
Are preferred. Such materials are obtained, for example, by melting synthetic or natural quartz powder in a flame using a combustible gas 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 represented by the following general formula (1)
In the represented Ruha hydrotalcite analogue compound is Ru mentioned.
This compound captures the above-mentioned impurity ions by substituting or coordinating a halogen ion and an organic acid ion in the epoxy resin composition with its own CO ₃ ^- ion,
It is considered that this has an effect of preventing the generation of hydrogen bromide due to the thermal decomposition of the brominated epoxy resin. Type of the hydrotalcite compound, x in the general formula (1), y, by distinction due ratio of the number of z, are divided into many types. Such hydrotalcite compounds are used alone or in combination of two or more.

[0020]

Embedded image

Such a compound has an average particle size of 5 μm or less from the viewpoint of dispersibility in the epoxy resin composition.
It is preferable that the maximum particle size is 30 μm or less. The content of the F component is preferably set to be 0.1 to 5% with respect to the resin component (A + B + C) of the epoxy resin composition. That is, when the amount is less than 0.1%, the effect of improving the high-temperature storage characteristics is not sufficiently exhibited, and when it exceeds 5%, a phenomenon of a decrease in moisture resistance is observed.

The epoxy resin composition for encapsulating a semiconductor of the present invention contains, if necessary, other additives conventionally used in addition to the above-mentioned components A to F.

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

Examples of the curing accelerator include tertiary amines, quaternary ammonium salts, imidazoles, organic phosphorus compounds and boron compounds. These compounds are used alone or in combination.

Examples of the releasing agent include 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 used.

The epoxy resin composition for semiconductor encapsulation of the present invention can be produced, for example, as follows. That is, the above-mentioned A to F components and the above-mentioned other additives are appropriately blended, the mixture is melted and mixed in a kneading machine such as a mixing roll machine in a heated state, cooled to room temperature, and then pulverized by a known means. The desired epoxy resin composition can be obtained by a series of steps of tableting as required.

The sealing of the 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 obtained in this way has an excellent performance of maintaining the reliability when left at high temperatures and also preventing the malfunction of the memory.

[0029]

As described above, the epoxy resin composition for semiconductor encapsulation of the present invention comprises a brominated epoxy resin (component (C)).
And the content of U and Th is 10 ppb or less and the average particle size is
In 0.1 to 30 [mu] m, and maximum particle size antimony oxide powder 44 .mu.m (D component), U, Th containing organic weight 10ppb or less
It contains a lower fused silica powder (component E) and a hydrotalcite compound (component F),
Since the component captures a halogen ion generated in a high-temperature atmosphere for a long period of time, a semiconductor device in which a semiconductor element is sealed using the component has excellent reliability in a high-temperature environment. In addition, the content of radioactive material,
Since it is greatly reduced, no malfunction of the memory occurs. Moreover, the above antimony oxide powder (D component)
The average and maximum particle size of the
Therefore, the fluidity of the epoxy resin composition for semiconductor encapsulation is high.
In addition, there is an advantage that burrs during molding are shortened.

Next, examples will be described together with comparative examples.

[0031]

Examples 1 to 10 and Comparative Examples 1 to 4 First, raw materials as shown in Table 1 below were prepared.

[0032]

[Table 1]

Next, the above-mentioned raw materials were blended in the proportions shown in Tables 2 to 4 below, kneaded with a mixing roll machine, cooled and pulverized to obtain a desired powdery epoxy resin composition.

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

The properties of the cured product of the powdered epoxy resin composition obtained as described above were examined and are shown in Tables 5 to 9 below.

[0038]

[Table 5]

[0039]

[Table 6]

[0040]

[Table 7]

[0041]

[Table 8]

[0042]

[Table 9]

In Tables 5 to 9, the spiral flow is EMMI-66 and the gel time is JIS-K-
It was measured according to 5966. The linear expansion coefficient and the glass transition temperature were measured by TMA (manufactured by Rigaku Corporation). The flexural modulus and flexural strength were measured with a Tensilon universal tester (manufactured by Toyo Baldwin Co., Ltd.). Volume resistivity is JIS-K-69
11 was measured. The measurement of element failure in a high temperature state was performed by assembling a semiconductor device by sealing a semiconductor element with a resin, exposing a total of 20 devices to a high temperature, and evaluating the number by which the number of conductive defects was determined. In the TCT test, a semiconductor element is sealed with a resin, and a semiconductor device is assembled.
A temperature cycle test was performed 2000 times at 150 ° C./5 minutes, and the number of cracks generated was measured. The α-ray dose was measured using an α-ray counter (Sumitomo Chemical Co., Ltd.).

From the results shown in Tables 5 to 9, it can be seen that the example product has higher reliability of the element when left in a high temperature state than the comparative example product, and also has a small α dose that causes memory malfunction.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08K 3/36 C08K 3/36 C08L 61/04 C08L 61/04 C09J 163/00 C09J 163/00 C09K 3/10 C09K 3/10 L H01L 23/29 H01L 23/30 R 23/31 (72) Inventor Tatsushi Ito 1-2-1 Shimohozumi, Ibaraki-shi, Osaka Nitto Electric Industry Co., Ltd. (72) Inventor Minoru Nakao Ibaraki-shi, Osaka 1-1-2 Shimohozumi Nitto Electric Industry Co., Ltd. (72) Inventor Fujio Kitamura 1-1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Electric Industry Co., Ltd. (72) Inventor Kazuo Ika Osaka 1-1-2 Shimohozumi, Ibaraki-shi Nitto Electric Industry Co., Ltd. (56) References JP-A-61-19625 (JP, A) JP-A-58-151318 (JP, A) JP-A 61-111569 (JP, ) Patent Akira 62-136860 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) C08G 59 / 20,59 / 40,63 / 00 C08K 3 / 20,3 / 22,3 / 36 C09J 163/00 C09K 3/10 H01L 23 / 29,23 / 31 C08L 61/04

Claims (6)

(57) [Claims] An epoxy resin composition for encapsulating a semiconductor, comprising the following components (A) to (F): (A) Epoxy resin. (B) a phenolic resin. (C) Brominated epoxy resin. (D) The content of U and Th is 10 ppb or less , and the average particle size is
In 0.1 to 30 [mu] m, antimony oxide powder outermost large diameter following 44 .mu.m. (E) A fused silica powder having a U and Th content of 10 ppb or less. (F) hydrotalcite analogue compound. 2. A hydrotalcite compound of the component (F).
The product is represented by the following general formula (1).
2. The epoxy resin composition for semiconductor encapsulation according to 1. Embedded image Wherein (C) equivalent of brominated epoxy resin component is 420 or more according to claim 1 or 2 semiconductor encapsulating epoxy resin composition. The content of wherein component (C) of the brominated epoxy resin, epoxy resin resin component (A + B + C component) of the composition, 1 to 10 claims set in wt% 1-3
The epoxy resin composition for semiconductor encapsulation according to any one of the above. 5. The fused silica of component (E) contains 5 to 100% by weight of spherical silica.
5. The epoxy resin composition for semiconductor encapsulation according to any one of 4. 6. The fused silica of component (E) has an average particle size of 1
The epoxy resin composition for semiconductor encapsulation according to any one of claims 1 to 5, wherein the epoxy resin composition has a maximum particle size of 96 µm or less.