JP2635621B2 - Resin composition for semiconductor device encapsulation - Google Patents

Description

Description: Object of the Invention (Industrial application field) The present invention relates to a resin composition used for encapsulating a semiconductor device, and in particular, a resin for encapsulating a semiconductor device containing a maleimide resin as a main component. Related to the composition.

(Prior Art) Resin encapsulation is widely used as a packaging technology for semiconductor devices such as ICs. In addition, a phenol novolac resin-curable epoxy resin is mainly used as a conventional sealing resin.

On the other hand, high integration of semiconductor devices in recent years has been remarkable, and accordingly, miniaturization of elements and increase in chip size have been rapidly progressing. In recent years, in the mounting technology of semiconductor devices, a method of mounting the semiconductor device by immersing it in a 260 ° C. solder bath has been used.

In this way, as core technologies and peripheral technologies change, more advanced properties are also required for sealing resins, and conventional epoxy resins satisfy the requirements for thermal shock resistance and high-temperature reliability. No longer. For example, it has become clear that encapsulating an LSI chip having a large and fine surface structure using the phenol novolak resin-curable epoxy resin composition causes the following problems.

The first problem is that cracks occur in the PSG film (phosphosilicate glass film) or SiN film (silicon nitride film) formed as a passivation film to protect the wiring layer on the chip surface, deteriorating device characteristics, In some cases, cracks occur in the entire chip, resulting in fatal failure. This is due to the stress applied to the chip from the mold layer of the sealing resin, and is particularly noticeable when a thermal cycle test is performed.

The second problem is that, when immersion treatment is performed in a solder bath at 260 ° C. during surface mounting, the resin mold layer is peeled off from the chip due to thermal shock, causing cracks in the resin layer, leading to fatal failure.

As measures against these problems, it is necessary to reduce the stress applied to the internal enclosure from the sealing resin and to improve the adhesion between the sealing resin layer and the passivation film on the chip surface. From this viewpoint, various low-stress epoxy resins have been studied in the field of epoxy resin sealing materials.

Also, without being limited to epoxy resin, for example, PPS
Various heat-resistant sealing materials such as (polyphenylene sulfide), polyhydroxyphenylene ether-based resin, maleimide-based resin, and liquid crystal polymer are also being studied. However, the following problems have been pointed out for these sealing materials.

High molding temperature Long molding time Poor releasability Bonding wire flow during resin molding (wire flow) Above all, maleimide resin-based sealing materials have good heat resistance and low thermal expansion coefficient, and Although it has excellent properties as an encapsulating material for use, it has the disadvantages described above, particularly inferior in releasability. Accordingly, various types of release agents have been studied in the field of maleimide resin-based sealing materials, but none of them exhibit sufficient release properties. For this reason, in the conventional maleimide resin-based sealing material, a large amount of an internal mold release agent has to be added, and there have been problems such as deterioration of the appearance of a molded product and severe contamination of a mold.

(Problems to be solved by the invention) In view of the above circumstances, an object of the present invention is to solve the problems in the conventional maleimide resin-based sealing material.

That is, the technical problem to be achieved by the present invention is to have an excellent mold release property and moldability by improving the internal mold release agent, and also to have an excellent heat resistance and a small thermal expansion characteristic of the maleimide resin. An object of the present invention is to provide a resin composition for encapsulating a semiconductor device which retains various advantages such as a rate.

[Constitution of the Invention] (Means for Solving the Problems and Their Functions) In order to achieve the above object, in the present invention, a maleimide resin is used in combination with a novolak-type phenol resin and / or an epoxy resin. An organic phosphine compound was used as a curing accelerator, and polyethylene wax was used as an internal release agent.

That is, the resin composition for encapsulating a semiconductor device according to the present invention comprises: A; a maleimide resin; B; a novolak-type phenol resin and / or an epoxy resin; C; an organic phosphine compound as a curing accelerator; It comprises a thermosetting resin composition containing a polyethylene wax as a mold agent.

The polyethylene wax used for the internal release agent in the present invention is a wax-like substance composed of polyethylene having a molecular weight of 500 to 4,000. This polyethylene wax greatly affects the moldability of the encapsulating resin composition according to the present invention, and is generally called polyethylene wax, or a carboxyl group introduced as a polar group by oxidation modification and acid modification. Can be used. Softening point is 65
C. to 140C are particularly preferred.

The amount of the polyethylene wax to be added is in the range of 0.2 to 19 parts by weight, preferably 0.4 to 5 parts by weight, based on 100 parts by weight of the resin component. In order to further improve the appearance of the molded article, an ester wax, a fatty acid wax, a fatty acid amide wax, or the like may be used in combination.

The maleimide resin which is a main component of the resin composition for sealing according to the present invention includes the following two types.

The first maleimide resin is a polymer of an N, N'-substituted bismaleimide compound represented by the following general formula (I).

(However, X in the formula is a divalent hydrocarbon group such as an alkylene group, a cycloalkylene group, a monocyclic or polycyclic arylene group, or -CH _2- , -CO-, -SO ₂ -,- CONH-
Represents a divalent hydrocarbon group bound by a divalent atomic group such as N) -N, N'-phenylenebismaleimide, N, N'- as a specific example of the monomer represented by the general formula (I). Hexamethylene bismaleimide, N, N'-diphenylmethane bismaleimide, N, N'-oxy-di-p-phenylenebismaleimide, N, N'-4,4'-benzophenone-bismaleimide, N, N'-p -Diphenylsulfonemaleimide, N, N '
-(3,3'-dimethyl) -methylene-di-p-phenylenebismaleimide, N, N'-4,4'-dicyclohexylmethanebismaleimide, N, N'-m-xylylene-bismaleimide, N, N '-P-xylylene-bismaleimide, N, N'
-(3,3'-diethyl) -methylene-di-p-phenylenebismaleimide and the like.

The second maleimide resin is a poly (phenylmethylene) polymaleimide represented by the following general formula (II).

(Where n in the formula is an integer of 1 to 5) In the present invention, any of the above maleimide resins may be used alone, or several types of maleimide resins may be used in combination.

In the encapsulating resin composition of the present invention, a novolak-type phenol resin and / or an epoxy resin are added in addition to the maleimide resin in order to improve the processability. That is, by adding the resin having a relatively low processing temperature, the drawback of a maleimide resin having a low processability due to a high processable temperature can be compensated.

The novolak-type phenol resin used for the above purpose has two or more hydroxyl groups per polymer molecule, and preferably has a softening point of 60C to 120C. The novolak type phenol resin includes a cresol novolak resin in addition to the phenol novolak resin.

Examples of the epoxy resin added for the above purpose include bisphenol A type epoxy resin, novolak type epoxy resin, alicyclic epoxy resin, and glycidyl ester type epoxy resin, and these may be used in combination. In particular, liquid or softening temperature at room temperature (25 ° C)
Those having a temperature of 120 ° C. or lower are preferred. When the novolak-type phenol resin and the epoxy resin are used in combination, the novolak-type phenol resin acts as a curing agent for the epoxy resin.

In the sealing resin composition of the present invention, it is desirable to add an organic phosphine compound as a curing accelerator (curing catalyst). Such organic phosphine compounds include, for example, trimethylphosphine, triethylphosphine, tributylphosphine, triphenylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, methyldiphenylphosphine, dibutylphenylphosphine, tricyclohexylphosphine, , 2-bis (diphenylphosphine) ethane, bis (diphenylphosphine) methane and the like, and one or more selected from these can be used.

The amount of the organic phosphine compound added is the resin component 100.
The amount is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 5 parts by weight based on parts by weight. If the amount is less than 0.01 part by weight, the curing speed is reduced and the moldability becomes poor. On the other hand, if it exceeds 20 parts by weight, heat resistance, moisture resistance and electrical properties deteriorate.

In the sealing resin composition of the present invention, in addition to the above components, if necessary, zircon, silica, alumina, aluminum hydroxide, glass, quartz glass, calcium silicate,
Asphalt, calcium carbonate, magnesite, clay, kaolin, talc, mica, asbestos, silicon carbide, boron nitride, molybdenum dioxide, lead compounds, lead oxide, zinc oxide,
An inorganic filler such as titanium white, carbon black, and antimony trioxide may be appropriately added.

Further, a similar optional component includes a silane coupling agent, and a thermal stress resistance may be improved by dispersing a low stress imparting material such as silicone oil or silicone rubber in an island shape.

Incidentally, the resin composition for encapsulating a semiconductor device according to the present invention,
Melt kneading by heating roll, kneader or extruder,
It can be easily produced by mixing using a special mixer after fine pulverization, or a method in which these are appropriately combined.

In addition, sealing of a semiconductor device using the resin composition of the present invention can be easily performed by using a normal sealing technique. The most common method is a low pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. When sealing, it is cured by heating,
Finally, a resin-sealed semiconductor device sealed with the cured resin composition is obtained. Heating for curing is preferably performed at 150 ° C. or higher.

EXAMPLES Hereinafter, the present invention will be described in more detail by describing Examples and Comparative Examples. In the following description, all “parts” indicate parts by weight.

Example 1 100 parts of poly (phenylmethylene) polymaleimide resin M-20 manufactured by Mitsui Toatsu Co., Ltd. and triphenylphosphine were used.
1.5 parts and fused silica powder GR-8 manufactured by Toshiba Ceramics Co., Ltd.
0 and 233 parts, carbon powder 1.8 parts, Nippon Unicar epoxy silane coupling agent A-187 2.4 parts,
Mix with polyethylene wax according to Table 1 and add 100
After kneading with a biaxial roll at 140140 ° C., the mixture was cooled. This was pulverized and then tableted to obtain a resin composition for encapsulating a semiconductor device of the present invention.

Examples 2 to 5 100 parts of poly (phenylmethylene) polymaleimide resin M-20 manufactured by Mitsui Toatsu Co., and 42 parts of phenol novolak epoxy resin Ep-152 manufactured by Yuka Shell Epoxy Co., Ltd. Phenol novolak resin BRG-5
55 and 25 parts, triphenylphosphine 1.7 parts, and Toshiba Ceramics Co., Ltd. fused silica powder GR-80 424 parts,
1.8 parts of carbon powder, 2.4 parts of an epoxysilane-based coupling unit A-187 manufactured by Nippon Unicar, and polyethylene wax as an internal mold release agent were mixed at the ratio shown in Table 1, and mixed at 70 to 110 ° C. After kneading with an axis roll, it was cooled.
This was pulverized and then tableted to obtain a resin composition for encapsulating a semiconductor device of the present invention.

Example 6 Diphenylmethane bismaleimide MB- manufactured by Mitsubishi Yuka
With 100 parts of 3000, 42 parts of phenol novolak type epoxy resin Ep-152 manufactured by Yuka Shell Epoxy, and 25 parts of phenol novolak resin BRG-555 manufactured by Showa Polymer Co.,
1.7 parts of triphenylphosphine, 424 parts of fused silica powder GR-80 manufactured by Toshiba Ceramic Co., and carbon powder
1.8 parts, 2.4 parts of Nippon Unicar's epoxy silane coupling agent A-187, and polyethylene wax as an internal release agent were mixed at the ratio shown in Table 1, and 100-140
After kneading with a twin-screw roll at ℃, the mixture was cooled. This was pulverized and then tableted to obtain a resin composition for encapsulating a semiconductor device of the present invention.

Comparative Example 1 A resin composition for encapsulating a semiconductor device was obtained in the same manner as in Example 1 except that the internal release agent in Example 1 was changed to zinc stearate and the mixing ratio shown in Table 1 was used.

Comparative Example 2 A resin composition for encapsulating a semiconductor device was obtained in the same manner as in Example 1 except that the internal release agent in Example 2 was changed to carnauba wax and the compounding ratio shown in Table 1 was used.

For each of the example product and the comparative product obtained above,
The following tests were performed. The results of these tests are also shown in Table 1.

First, the molded product was molded using a mold for measurement of release weight, and the releasability of the molded product from the mold was measured with a push-pull gauge. At the same time, the appearance of the molded article and the stain on the mold were also observed.

Next, the volume resistivity, the glass transition point, the coefficient of thermal expansion, and the bending strength were measured as various characteristics of the molded and cured resin. In addition, these characteristic tests were performed by the following method.

<Volume Resistivity> A sample subjected to transfer molding at 175 ° C. for 3 minutes in accordance with JIS k-6911 and after-curing (175 ° C., 8 hours) was used. The measurement conditions were as follows: DC 500 V was applied, and the value of the volume resistivity at a measurement temperature of 150 ° C. in one minute was shown.

<Glass Transition Point, Thermal Expansion Coefficient> The same molding and after-curing treatment as described above was performed, and a sample of about 5 mm × 20 mm was cut out from the runner part. The glass transition point of this sample and the coefficient of thermal expansion from room temperature (25 ° C.) to 200 ° C. were calculated at a temperature rise of 5 ° C./min using a thermal expansion coefficient measuring device.

<Bending strength> This was performed using a sample molded and after-cured in the same manner as described above according to JIS k-6911.

As is evident from the results shown in Table 1, the resin compositions of the above Examples were more releasable than the Comparative Examples in a molding test using a molding die for weight measurement, and the stains of the molded product were reduced. And it is excellent in all the characteristic values. In the comparative example using carnauba wax or zinc stearate as the release agent, the releasability was poor even though the amount of the release agent added was larger than in the examples. In addition, it can be seen that the appearance of the molded product and the stain resistance of the mold are inferior, and the physical properties such as volume resistivity, water absorption, glass transition point, thermal expansion coefficient and bending strength are also reduced.

[Effects of the Invention] As described in detail above, according to the present invention, good moldability can be imparted without deteriorating the electrical and mechanical properties of the maleimide resin sealing material. Therefore, it is of great value in the field of semiconductor device sealing materials in which the importance of heat resistance and thermal shock resistance is increasing.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08L 61/10 LNB C08L 61/10 LNB 61/32 LNK 61/32 LNK LNM LNM LNP LNP H01L 23 / 29 H01L 23/30 R 23/31

Claims (2)

(57) [Claims] 1. A semiconductor encapsulating resin composition comprising a thermosetting resin composition containing the following components A to D: A; a maleimide resin, B; a novolak-type phenol resin and / or an epoxy resin, C; Organic phosphine compounds as accelerators; D; polyethylene waxes as internal mold release agents. 2. The resin composition for encapsulating a semiconductor device according to claim 1, wherein said polyethylene wax is an oxidized or acid-modified polyethylene wax.