JP2899096B2 - Semiconductor device - Google Patents

Description

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

[Conventional technology]

Conventionally, semiconductor devices such as transistors, ICs, and LSIs have been encapsulated with ceramic packages and the like to form semiconductor devices, but recently, from the viewpoint of cost and mass productivity,
Resin sealing using a plastic package has become mainstream. For this type of resin sealing, an epoxy resin has been conventionally used, and good results have been obtained. However, due to technological innovation in the field of semiconductors, the degree of integration has been increased, the device size has been increased, and the wiring has become finer, and the packages have also become smaller and thinner. On the other hand, there is a demand for further improvement in reliability (reduction of thermal stress of the obtained semiconductor device, reliability of humidity resistance, reliability against thermal shock test, etc.). In particular, in recent years, the size of semiconductor elements has been increasing in size, and there has been a demand for further improvement in performance over a thermal cycle test (TCT test), which is an accelerated test for evaluating the performance of a semiconductor sealing resin. In addition, surface mounting has become the mainstream as a mounting method for semiconductor packages. For this reason, even if the semiconductor package is immersed in a molten solder in a state of absorbing moisture, it is required that the package does not crack or swell. It has become so.

[Problems to be solved by the invention]

Conventionally, in response to the above request, the TCT test
In order to improve each property to be evaluated, it has been studied to modify an epoxy resin using a silicone compound and thereby reduce thermal stress. In addition, to improve the adhesion between the lead frame and the encapsulating resin has been studied to improve the crack resistance during solder immersion, but in fact, both have not yet achieved sufficient effects. It is.

As described above, the conventional epoxy resin materials for sealing do not satisfy both the results of the TCT test and the properties of crack resistance during solder immersion. For this reason, there is a strong demand for improvement of the above two characteristics so as to be able to cope with an increase in the size of the semiconductor element and surface mounting due to the above technical innovation.

The present invention has been made in view of such circumstances,
It is an object of the present invention to improve semiconductor characteristics evaluated by a TCT test and to provide a semiconductor device having excellent crack resistance during solder immersion.

[Means to solve the problem]

In order to solve the above-mentioned object, a semiconductor device of the present invention has a configuration in which a semiconductor element is sealed with an epoxy resin composition containing the following components (A) to (C).

(A) A novolak-type polyglycidyl ether containing one or more structural units derived from naphthol in one molecule.

(B) A novolak curing agent represented by the following general formula (I).

[In the above general formula (I), X is H or CH ₃ . Also, 2 ≦ m ≦ 50. (C) Inorganic filler.

[Action]

That is, the present inventors have conducted a series of studies in order to obtain a sealing resin having various properties evaluated by the TCT test and excellent crack resistance during solder immersion. As a result, when the novolak type polyglycidyl ether having the above-mentioned special skeleton structure and the novolak curing agent represented by the above general formula (I) are used, each property evaluated by the TCT test and the crack resistance during solder immersion are obtained. The present inventors have found that an excellent sealing resin can be obtained in both cases, and have reached the present invention.

 Next, the present invention will be described in detail.

The epoxy resin composition used in the present invention is obtained by using an epoxy resin having a special skeleton structure (component A), a special curing agent (component B), and an inorganic filler (component C). Yes, it is usually in the form of a powder or tablet.

Epoxy resin having the above special skeleton structure (component A)
Represents one unit of a structural unit derived from naphthol in one molecule.
Novolak-type polyglycidyl ether containing at least one such compound. Such a special novolak-type polyglycidyl ether is represented, for example, by the following general formula (IV). In the following general formula (IV), the mode of condensation between the phenol component represented by the number of repetitions n and the naphthol component represented by the number of repetitions m is not particularly limited, such as alternating, random, and block. It becomes an aspect of.

In the general formula (IV), the number of repetitions n is 0.
≦ n ≦ 10, and the number of repetitions m is preferably in the range of 1 ≦ m ≦ 20, and the value of n + m is preferably 2 ≦ n + m ≦ 20.
Is preferable. Among them, as a novolak type polyglycidyl ether, 3 represented by the following structural formula
It is preferable to use a nucleus.

This novolak-type polyglycidyl ether is obtained, for example, by reacting naphthol and cresol via an aldehyde component to produce a naphthol-cresol condensate and reacting it with epichlorohydrin. The condensation degree of the naphthol-cresol condensate is 2 to
A range of 5 is preferred. Examples of the naphthol include at least one of α-naphthol and β-naphthol, and cresols include p-cresol and o-naphthol.
And at least one of cresols. Examples of the aldehyde component include, but are not limited to, formaldehyde, and other aldehydes other than formaldehyde may be used. The use ratio of naphthol and cresol is preferably set to a ratio of 0.2 to 2 mol of cresol to 1 mol of naphthol, particularly preferably 0.4 to 0.6 mol. In the combination of naphthol and cresol, a combination of α-naphthol and p-cresol is preferable.

The special curing agent (component B) is represented by the following general formula (I)
Is a novolak curing agent having a structure represented by the formula: In the following general formula (I), the mode of condensation between the phenol component and the xylene component is the mode of alternate condensation.

[In the above general formula (I), X is H or CH ₃ . Also, 2 ≦ m ≦ 50. In the general formula (I), the number m of repetitions is in the range of 2 ≦ m ≦ 50. Among them, a curing agent represented by the above general formula (I) is preferably a curing agent represented by the following structural formula.

Such a special novolak type curing agent can be obtained, for example, by condensing a phenolic compound with xylene. The degree of condensation of the novolak curing agent is preferably in the range of 2 to 100. Particularly preferably, it is 2 to 50. Examples of the phenolic compound include phenol and cresol. Examples of the xylene include p-xylene and o-xylene, and particularly preferred is p-xylene. The curing agent thus obtained preferably has a hydroxyl equivalent of 170 to 200 and a softening point of 60 to 150 ° C.

The mixing ratio of the special epoxy resin (component A) and the special curing agent (component B) is such that the hydroxyl group in the curing agent is 0.1 per equivalent of epoxy group in the special epoxy resin.
It is preferable to mix them in an amount of 8 to 1.2 equivalents.

The inorganic filler (component C) used together with the component A and the component B is not particularly limited.
Conventionally known materials are used, and examples thereof include quartz glass powder, talc, silica powder, and alumina powder.
Particularly preferred is silica powder. In the case of silica powder, the content of such an inorganic filler is preferably set to 50% by weight (hereinafter abbreviated as “%”) or more of the entire epoxy resin composition. It is particularly preferably at least 70%, and more preferably at least 80%. That is, when the content of the inorganic filler is less than 50%, the effect of improving each property by the TCT test and the effect of improving the body cracking property at the time of solder immersion are significantly reduced.

Further, in the epoxy resin composition used in the present invention, it is preferable to use a silicone compound in addition to the components A to C in order to reduce internal stress. Examples of the silicone compound include the following general formulas (II) and (III)
And used alone or in combination.

When such a silicone compound is blended, the blending amount is preferably set so as to be 5% or less of the entire epoxy resin composition. Particularly preferably, 0.5 to 3
%.

In addition to the above components, the epoxy resin composition used in the present invention may further comprise, if necessary, other additives such as a conventionally known curing accelerator such as a tertiary amine, a quaternary ammonium salt, imidazoles and boron. Compounds and the like are appropriately compounded. These are used alone or in combination.
Further, flame retardants and pigments such as antimony trioxide and phosphorus compounds, and coupling agents such as silane coupling agents can be blended.

The epoxy resin composition used in the present invention can be produced, for example, as follows. That is, first, the above-mentioned components A to C, and in some cases, a silicone compound and other additives are used, and these are blended at a predetermined ratio. Then, the mixture is subjected to a kneading machine such as a mixing roll machine, melt-kneaded in a heated state, cooled to room temperature, then ground by a known means, and subjected to a series of steps of tableting as necessary. This makes it possible to produce the desired epoxy resin composition. Prior to compounding each component, the above-mentioned A
The component or the component B may be modified, and the modified product and the remaining components may be blended.

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 obtained in this manner uses the epoxy resin composition containing the epoxy resin (A component) having the special skeleton structure and the novolak-type curing agent represented by the general formula (I). Therefore, the properties evaluated in the TCT test are improved, and the steel has excellent crack resistance during solder immersion.

〔The invention's effect〕

As described above, the semiconductor device of the present invention uses the epoxy resin (component A) having a special skeleton structure and the special epoxy resin composition containing the novolak type curing agent represented by the general formula (I). TCT
The characteristics evaluated by the test are improved and the life is extended.
Also, no package crack occurs during solder immersion after moisture absorption. In particular, high reliability as described above is obtained in a large semiconductor device having 8 pins or more, especially 16 pins or more, or a semiconductor element having a long side of 4 mm or more by sealing with the special epoxy resin composition. To be able to
This is a major feature.

 Next, examples will be described together with comparative columns.

First, prior to Examples, silicone compounds a to f shown in Table 1 below were prepared.

[Examples 1 to 26, Comparative Examples 1 to 3] The silicone compounds shown in Table 1 above and the components shown in Table 2 below were blended in the proportions shown in Table 2 and mixed on a mixing roll machine (temperature (100 ° C.) for 3 minutes. Next, this was cooled and solidified, and then pulverized to obtain a desired powdery epoxy resin composition.

Using the powdered epoxy resin compositions obtained according to the above Examples and Comparative Examples, a semiconductor device is formed by transfer forming a semiconductor element (conditions: 175 ° C. × 2 minutes, 175 ° C. × 5 hours post-curing). I got This package is 80-pin QF
P (quad flat package, size: 20 x 14 x 2m
m) and the die pad size is 8 × 8 mm.

The semiconductor device obtained in this manner was subjected to −50 ° C.
The TCT test was performed while changing the number of cycles from / 5 minutes to 150 ° C./5 minutes, and the number of package cracks was measured. 85 ℃ / 8
After leaving it in a 5% RH constant-temperature bath for various periods of moisture absorption to allow it to absorb moisture, a test was conducted in which it was immersed in a 260 ° C. solder melt for 10 seconds, and the number of package cracks generated was measured. The results are shown in Table 3 below.

From the results in Table 3, the package cracks occur in the comparative example product as the number of cycles increases in the TCT test.
In the crack resistance test during solder immersion, the moisture absorption time was 48
All packages cracked over time. On the other hand, in the example product, the number of generated cracks was smaller than in the comparative example product in both the TCT test and the crack resistance test during solder immersion. From this, the example product is TC
It can be seen that both the T test and the crack resistance during solder immersion are excellent.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 23/31 (72) Inventor Nakamura ▲ Yoshi ▼ Shin 1-2-1 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Tsukasa Yoshida 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (56) References JP-A-2-235918 (JP, A) JP-A-2-189326 (JP, A) JP-A-4-96929 (JP, A) JP-A-4-96928 (JP, A) JP-A-3-220219 (JP, A) JP-A-3-21627 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) C08L 63/00-63/10 H01L 23/29 C08G 59/20-59/32 C08G 59/62

Claims (10)

(57) [Claims] 1. A semiconductor device comprising a semiconductor element encapsulated with an epoxy resin composition containing the following components (A) to (C). (A) A novolak-type polyglycidyl ether containing one or more structural units derived from naphthol in one molecule. (B) A novolak curing agent represented by the following general formula (I). [In the above general formula (I), X is H or CH ₃ . Also, 2 ≦ m ≦ 50. (C) Inorganic filler. 2. An epoxy resin composition for encapsulating a semiconductor, comprising the following components (A) to (C). (A) A novolak-type polyglycidyl ether containing one or more structural units derived from naphthol in one molecule. (B) A novolak curing agent represented by the following general formula (I). [In the above general formula (I), X is H or CH ₃ . Also, 2 ≦ m ≦ 50. (C) Inorganic filler. 3. The novolak-type polyglycidyl ether as the component (A) is a novolak-type polyglycidyl ether represented by the following general formula (IV).
The epoxy resin composition for semiconductor encapsulation according to the above. 4. In the above formula (IV), the number of repetitions n
Is in the range of 0 ≦ n ≦ 10, the repetition number m is in the range of 1 ≦ m ≦ 20, and the sum of the repetition number n and the repetition number m (n
The epoxy resin composition for semiconductor encapsulation according to claim 3, wherein (+ m) is set in a range of 2 ≦ (n + m) ≦ 20. 5. The epoxy resin composition for semiconductor encapsulation according to claim 3, wherein the novolak type polyglycidyl ether as the component (A) is represented by the following structural formula. 6. The novolak type glycidyl ether as the component (A) is obtained by reacting naphthol and cresol via an aldehyde component to produce a naphthol-cresol condensate and reacting it with epichlorohydrin. Wherein the degree of condensation between the naphthol and cresol is in the range of 2 to 5.
The epoxy resin composition for semiconductor encapsulation according to any one of (5). 7. The naphthol is α-naphthol,
The epoxy resin composition for semiconductor encapsulation according to claim 6, wherein the cresol is p-cresol. 8. The novolak curing agent as the component (B) is represented by the following structural formula:
The epoxy resin composition for semiconductor encapsulation according to any one of (7). 9. The semiconductor device according to claim 1, wherein said semiconductor element has a size of 8 pins or more or a long side of 4 mm or more. 10. The semiconductor device according to claim 1, wherein the size of the semiconductor element is 16 pins or more or its long side is 4 mm or more.
13. The semiconductor device according to claim 1.