JPS606383B2 - Coating resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating resin composition, and more particularly to a resin composition suitable for coating a member containing woven aluminum.

Hereinafter, the case of semiconductor device encapsulation, which is a typical application, will be explained as an example.

Semiconductor devices are often entirely encapsulated in resin to protect them from the external environment, and methods of resin encapsulation include transfer molding, casting, potting, dipping, and powder molding. There are painting methods, etc., and the appearance shape of the object to be sealed,
An appropriate method is selected depending on the production volume and other factors. For example, transfer molding methods are used for mass production of integrated circuits and transistors. On the other hand, as resins for semiconductor encapsulation, epoxy resins or silicone resins, which have excellent electrical and mechanical properties and especially good heat resistance, are used in most semiconductor devices, and epoxy resins are cheaper than silicone resins. Therefore, epoxy resin is usually used unless silicone resin is required due to particular temperature requirements. Generally, bisphenol-type epoxy resins, cycloaliphatic-type epoxy resins, and novolak-type epoxy resins are used for semiconductor encapsulation, but as the heat resistance of semiconductors improves, encapsulation resins are also required to have high heat resistance. Recently, novolac type epoxy resins have been widely used.

By the way, the curing agents for the above-mentioned epoxy resins are roughly divided into two types: saddle anhydride curing agents and amine curing agents, but acid anhydride curing agents have good workability and good resin properties. Moreover, it is more advantageous in terms of safety and health, so it is used more often than amine-based curing agents.

In the process of sealing mass-produced semiconductor devices, using only the above-mentioned epoxy resin and curing agent causes resin curing to be slow and has problems with workability, so it is generally recommended to use an amine-based catalyst to accelerate curing. It is customary. When a semiconductor device sealed with such a sealing resin is exposed to a high temperature environment, moisture permeates through the resin layer and reaches the aluminum A electrode, which is an essential component of the semiconductor device.

The acid anhydride of the resin component dissolves in this water, making it acidic, or the amine catalyst dissolves, making it alkaline. By the way, since aluminum is an amphoteric element, it dissolves in both acid and alkali, causing the A electrode to disappear and the semiconductor device to lose its functionality. This invention was made in view of the above-mentioned drawbacks of the encapsulating resin, and aims to provide a resin for encapsulating a semiconductor device that does not cause corrosion of the A terminal electrode of the semiconductor device even in a high-temperature atmosphere. be.

As a result of research conducted by the inventors, it has been found that alkali is a greater cause of the disappearance of the AZ electrode than acid.

This invention was made based on the above findings, and uses an amine catalyst salted with an acid as a curing accelerator (catalyst). That is, as the epoxy resin, a bisphenol type epoxy resin, a cycloaliphatic type epoxy resin, or a novolak type epoxy resin is used, and as the bisphenol type epoxy resin, there are Epicoat 828, Epicoat 815, etc. (product name of Shell Chemical Co., Ltd.), GY250, GY252, etc. (Ciba product name), and cycloaliphatic epoxy resins include Epikot 192, Epicoat 190, Epicoat 172 (Shell Chemical Company product name), CY185, CY183, C
Y182, CY180, CY179, CY178, CY
175 (Ciba product name), and novolac type epoxy resins include Epikot 154 and Epikot 152.
etc. (Shell product name), EPNI139, EPNI1
38 etc. (Ciba product name), DEN438DEN431
(Dow Chemical Company product name).

However, as mentioned above, nopolac type epoxy resin exhibits the most favorable characteristics. Examples of the curing agent for this epoxy resin include methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, and tetrahydride.

Phthalic anhydride, methylenephthalic anhydride,
Examples include chlorendic anhydride, pyromellitic anhydride, dodecenyl succinic anhydride, and among them, methylhexahydrothermal phthalic acid and hexahydrophthalic anhydride provide particularly preferred cured products. Catalysts for the combination of the above epoxy resin and curing agent include {a-imidazole type (e.g. 2-ethylimidazole, 2-methylimidazole,
2-phenylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecyl imidazole, 1-vinyl-2-methylimidazole, 1-vinyl-2-ethylimidazole , 1,3-bis[imidazolyl-2']benzole, 1,4-bis[imidazolyl-2']
'] Benzol, 2-phenyl-4-methylimidazole, 1-vinyl-2,4-dimethylimidazole, 1
-vinyl-2-ethyl-4-methylimidazole, 1-
{b) tertiary amines (e.g. triethylamine, 2,4,6-dimethylaminomethylphenol, penzyldimethylamine, a- methylbenzylmethylamine, piverizine, etc.),
and {c} latent curing agents (eg, boron trifluoride and its tsuba compounds).

Aliphatic carboxylic acids (e.g., formic acid, acetic acid, propionic acid, n-butyric acid, isobutyric acid, n-valeric acid, trimethylacetic acid, caproic acid, n-heptanoic acid, caprylic acid) are used as acids for forming salts of the above amine catalysts. , belargonic acid, fluoroacetic acid, chloroacetic acid, promic acid, iodoacetic acid, dichloroacetic acid, trichloroacetic acid, a-chloropropionic acid,
B-chloropropionic acid, glycolic acid, lactic acid, methoxyacetic acid, thioglycolic acid, cyanacetic acid, glyoxylic acid, malonic acid, acrylic acid, vinylacetic acid, phenylacetic acid, etc.).

Examples of the present invention will be shown below in comparison with comparative examples, and the effects of the present invention will be demonstrated by sealing an actual semiconductor integrated circuit and performing a pressure cooker test (unless otherwise specified, 120 oo
, 2 atm, and high temperature), and the failure rate is shown as the failure rate at that time.

Example 1 The epoxy resins and acid anhydride curing agents used, as well as the combinations of amine catalysts and carboxylic acids, are shown in Tables 1 and 2, respectively.

Table 1 Table 2 A 14-pin integrated circuit was sealed using a combination of the compositions shown in Tables 1 and 2 above, and a high-temperature test was conducted to determine the corrosion of the electrodes. The results of the investigation are shown in Table 3.

Note to Table 3 *...×/20 indicates that out of 20 samples, X pieces were internally corroded.

Each test composition shall contain 65% silica filler.

Comparative Example 1 For comparison with Example 1 above, the compositions of the epoxy resin and curing agent were the same as A, B, C, and D shown in Table 1, and the amine catalyst was Using compositions G and 1, which are the same as E and F shown in Table 2 but do not contain carboxylic acid, samples similar to those in Table 3 were prepared and subjected to high temperature high temperature tests. Table 4 shows the results. .

The results of Tables 3 and 4 are illustrated in FIG.
Table 4 Example 2 Next, a cycloaliphatic epoxy resin was also used as the epoxy resin, and a saddle anhydride different from that in Example 1 was used as the curing agent.
A combination of tables was used.

Table 5 Samples were prepared by combining the composition prepared as shown in Table 5 above with an imidazole catalyst, a tertiary amine catalyst, and various carboxylic acids prepared as shown in Table 6. did.

Table 6 As mentioned above, the same tests as in Example 1 were conducted on Examples in which the compositions shown in Tables 5 and 6 were combined and prepared.

The results are shown in Table 7. Table 7 Comparative Example 2 For comparison with Example 2 above, the composition of the epoxy resin and curing agent was the same as 1, J, K, and L shown in Table 5, and the amine catalyst was M, N, 0 shown in Table 6
, P, respectively. Samples similar to those in Table 7 were prepared using compositions Q, R, S, and T that do not contain carboxylic acid, and a high temperature and high humidity test was conducted. Table 8 shows the results.

The results of Tables 7 and 8 are illustrated in FIG. 2.
Comparing the Examples and Comparative Examples in Table 8 and above, the effect of adding carboxylic acid to the amine catalyst according to the present invention is extremely clear.

Next, the water absorption of the cured product, which is an important property for a resin for encapsulating semiconductor devices, was measured for all the samples of the above-mentioned Examples and Comparative Examples.

The shape of the sample was a cube with 6 sides x 20 willows x 4 sides, which was immersed in water of 120 qo and 2 atm, and the change in weight was measured at predetermined intervals. The results are shown in FIG. 3 for samples 1 to 16 and in FIG. 4 for samples 17 to 24. From this point as well, it is clear that the embodiments of the present invention are significantly superior. Incidentally, FIG. 3 also shows for reference the results of similar measurements on one type of commercial product that is said to have good characteristics as a resin for encapsulating semiconductor devices. Regarding the catalyst compositions that have a large relationship with the sealing resin A Yugiri extreme corrosion rate, the conventional amine catalyst-only compositions G, JP, Q, R, S and T shown in Comparative Examples 1 and 2. and compositions E, F, M, shown in Examples 1 and 2 of this invention.
The acidity and basicity (PH value) of N, 0 and P were each dissolved in pure water for 100 days and measured at 250 degrees.

The results are shown in Table 9. Table 9 As is clear from Table 9, the conventional amine catalyst alone has a basic pH value of 8.5 to 9.0, whereas the pH value of the example of the present invention is 8.5 to 9.0. Value is 6.0-7.0
and is close to neutrality, which clearly corresponds to the corrosion results of the A〆 electrode mentioned above.

Furthermore, the change in pH value depending on the amount of carboxylic acid added to the amine catalyst was determined by changing the blending ratio of 2-ethyl-4-methylimidazole to acetic acid for Composition E in Table 2 used in Example 1. Table 1: Make changes as shown in Table 1, dissolve the 100% pure water composition in the same way as above, and adjust the pH to 25%.
The results measured by the meter and the first scale table are also listed here.

Table 10 Samples 25 to 30 prepared by combining the catalyst composition thus obtained with composition A shown in Table 1 were subjected to the same tests as in Examples 1 and 2. Shown in the table.

Table 11 As can be seen from the experimental results, the higher the basicity of the composition, the higher the corrosion rate of A Yuka Goku.

In the above explanation, it was described that the amine catalyst is used in advance as a salt with a carboxylic acid, but both may be separately blended into the epoxy resin.

Further, the resin of the present invention is not limited to use for semiconductor encapsulation, but is effective for use in resin encapsulation and coating of aluminum metal coatings and other devices containing aluminum metal.
Furthermore, although the above embodiments have been described only when the composition is neutral or alkaline, the effects of the present invention can be expected even if the composition is somewhat acidic. That is, if the pH value is more than 4 and less than 9, it is effective. As detailed above, in this invention, since an acid that forms a salt with an amine catalyst is added, corrosion of the aluminum metal contained in the member to be coated is suppressed, and a highly reliable coating resin composition can be obtained. .

[Brief explanation of drawings]

Fig. 1 is a diagram showing the test results of the product shown as Example 1 of the present invention and the subordinate product shown as Comparative Example 1, and Fig. 2 is a diagram showing the test results of the product shown as Example 2 of the present invention and Comparative Example 2. Figure 3 shows the water absorption test results for Example 1 and Comparative Example 1, and Figure 4 shows the test results for Example 2 and Comparative Example 2. FIG. 5 is a diagram showing the results of a water absorption test, and FIG. 5 is a diagram showing the test results for resins whose pH values were changed with specific composition combinations. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1 100 parts by weight of epoxy resin, 80 parts by weight of acid anhydride curing agent
~140 parts by weight, and a coating resin composition comprising 0.42 to 0.55 parts by weight of an amine catalyst and a carboxylic acid that accelerate the reaction of the curing agent.