JPH10287793A - Epoxy resin composition for semiconductor sealing and semiconductor device sealed therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellent in humidity resistance and soldering reflow resistance by mixing an epoxy resin containing a specified or larger amount of an epoxy resin having a dicyclopentadiene skeleton with a compound having a plurality of phenolic hydroxyl groups, a phosphorus compound and an inorganic filler in a specified ratio. SOLUTION: The epoxy resin used contains at least 70 wt.% epoxy resin represented by formula I. The phosphorus compound used is one represented by formula II. The inorganic filler is used in an amount of 60-95 wt.% based on the total weight of the composition. The epoxy resin used may entirely consists of an epoxy resin represented by formula I or a combination thereof with another epoxy resin having at least two epoxy groups. The resin used in combination is one represented by formula III (wherein R is H or a 1-4C alkyl; and m is 0-6). The compound having a phenolic hydroxyl group is desirably a compound represented by formula IV (wherein p is 0-6). The inorganic filler used is exemplified by a fused silica powder.

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 which is excellent in moisture resistance and solder reflow resistance in surface mounting of a semiconductor element, and a resin-encapsulated semiconductor device using the same.

[0002]

2. Description of the Related Art Conventionally, diodes, transistors, I
Although semiconductor devices such as C and LSI are sealed with a thermosetting resin, heat resistance is particularly high in semiconductor devices such as IC and LSI.
An epoxy resin composition obtained by curing an orthocresol novolak type epoxy resin having excellent moisture resistance with a phenol novolak resin and blending an inorganic filler such as fused silica or crystalline silica as a filler is used. However, in recent years, as the integration of semiconductor devices such as ICs and LSIs has increased, the size of chips has gradually increased, and packages have become smaller and thinner QFPs, SOPs, TPSs, which are surface-mounted from conventional DIP types.
SOP, SOJ, TQFP, PLCC have been changed. That is, a large chip is sealed in a small and thin package, and cracks are generated by thermal stress, and problems such as a decrease in moisture resistance due to these cracks are greatly highlighted. In particular, in the process with soldering, since equipment such as IR reflow and VPS reflow is used, the moisture contained in the package is vaporized by being rapidly exposed to a high temperature of 200 ° C. or more, and this vapor pressure is reduced. It acts as peeling stress at the interface between the resin and the insert such as the element / lead frame, and peeling at these interfaces.
In the case of a thin package, there is a problem that blisters and cracks are generated and the moisture resistance is deteriorated. Various studies have been made to solve such problems.Investigations using various resins have revealed that the adhesive strength to the insert, the moisture absorption of the cured product, and the strength at high temperatures are important. I have. On the other hand, when a strong adhesive force is exhibited to the insert, there has been a problem that the releasability from a molding die is poor. Although increasing the amount of the filling material is effective for lowering the moisture absorption and increasing the strength, there is a problem in that the fluidity is reduced, which is also affected by the viscosity of the resin. For this reason, even in a system that can reduce the water absorption of a cured product of a resin, there is a problem that the viscosity of the system is high and a large amount of filler cannot be added. Further, some resin systems have a problem that the storage stability of the epoxy resin composition is extremely poor. Therefore, development of a highly reliable semiconductor sealing resin composition suitable for sealing these large chips is desired.

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to provide an epoxy resin composition used for semiconductor encapsulation which achieves both adhesion to an insert and release from a molding die. An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation which has significantly improved soldering stress resistance of a package when mounted on a substrate of a semiconductor package having excellent fluidity despite a large amount of filler. .

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that an epoxy resin containing a specific resin and a specific compound as a curing agent in combination is contained. It has been found that the resin composition is excellent in low moisture absorption and high adhesion, and at the same time is effective against cracks during solder mounting on a substrate. Further, when the epoxy resin composition contains a specific phosphorus compound as a curing accelerator, it is possible to obtain an epoxy resin composition which is rich in fluidity, can be highly filled with a filler, and has excellent storage stability. This led to the completion of the present invention based on this finding. That is, the present invention provides the following (A) to (D)
The present invention relates to an epoxy resin composition for semiconductor encapsulation comprising components and a resin-encapsulated semiconductor device using the same. (A) an epoxy resin represented by the following structural formula 1,

Embedded image (B) a compound having two or more phenolic hydroxyl groups in one molecule, (C) a phosphorus compound represented by the following structural formula 2

Embedded image And (D) 60 to 95% by weight based on the total amount of the epoxy resin composition
Inorganic filler.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin of the component (A) may consist solely of the epoxy resin represented by the above structural formula 1, or may contain two or more epoxy groups in one molecule. Other epoxy resins may be used in combination up to 30% by weight of the total epoxy resin. Examples of the epoxy resin used in combination include orthocresol novolak type epoxy resin, phenol novolak type epoxy resin, bisphenol A type epoxy resin, and the like. Preferably, the epoxy resin represented by the following structural formula 3 is used as the total epoxy resin. On the other hand, when it is used at a ratio of 2 to 30% by weight, preferably 10 to 20% by weight, the fluidity can be further improved, which is preferable from the viewpoint of increasing the filling of the filler. In this case, 2% by weight
If the amount is less than 30%, the effect of improving the fluidity is poor. If the amount exceeds 30% by weight, the releasability may be deteriorated.

Embedded image (In the formula, R represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms, and m represents an integer of 0 to 6.) The epoxy resin represented by Structural Formula 3 is used singly. Or two or more of them may be used in combination.

Examples of the compound having two or more phenolic hydroxyl groups in one molecule of the component (B) used as a curing agent include a phenol novolak resin and a cresol novolak resin. It is preferable to use a compound represented by the following formulas from the viewpoint of increasing the adhesive strength and reducing the moisture absorption. Further, two or more of these may be used in combination.

Embedded image (In the formula, p represents an integer of 0 to 6.)

[0007] The phosphorus compound represented by the structural formula 2 of the component (C) is used as a curing accelerator. By using this phosphorus compound, an epoxy resin composition which is rich in fluidity and excellent in high filling of the filler. Things are obtained. Further, the epoxy resin composition of the present invention containing the phosphorus compound is also excellent in storage stability. The phosphorus compound represented by the structural formula 2 is obtained, for example, by the following method. 1. 41.6 g of triferniphosphine in acetone 12
Dissolve in 0 g. 2. 17.6 g of p-benzoquinone are dissolved in 120 g of acetone. 3. Mix the solutions of 1 and 2 at room temperature to 80 ° C. 4. The precipitated yellow-brown crystals were filtered out and taken out according to Structural Formula 2
Used as a phosphorus compound represented by Here, a mixed solvent of acetone and toluene or the like may be used as the solvent instead of the acetone. The proportion of the component (C) is usually 0.1 to 10 parts by weight, preferably 2 to 7 parts by weight, per 100 parts by weight of the total epoxy resin. Further, as a curing accelerator, a curing accelerator other than the phosphorus compound represented by the structural formula 2, for example, triphenylphosphine, 1,8-diazabicyclo (2.
4.6) Undecene-7 or the like may be used in combination.

Further, the epoxy resin composition of the present invention comprises:
A releasing agent may be added in order to have good releasability from the mold during molding. As the release agent, an oxidized or non-oxidized polyolefin is used in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the total epoxy resin.
It is preferable to add 5 parts by weight. This means that if it is less than 0.01 part by weight, sufficient release properties cannot be obtained, and
If it exceeds 10 parts by weight, the adhesiveness may be impaired. Examples of the oxidized or non-oxidized olefin include low molecular weight polyethylene having an average molecular weight of about 500 to 10,000 such as H4, PE, and PED series manufactured by Hoechst. Further, it may be used in combination with other release agents such as carnauba wax, montanic acid ester, montanic acid, and stearic acid. When these other release agents are used in addition to the oxidized or non-oxidized polyolefin, the mixing ratio thereof is usually 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the total epoxy resin.
A range of 5 to 3 parts by weight is suitable.

By the way, when the epoxy resin represented by the structural formula 1 is used, the flame retardancy of the epoxy resin composition decreases. For this reason, it is preferable to add a flame retardant in an epoxy resin composition using a conventional orthocresol type epoxy resin in a larger amount than that used. Examples of the flame retardant suitably used in the present invention include an organic flame retardant such as a brominated epoxy resin and an inorganic flame retardant such as antimony trioxide. Further, when more of these flame retardants are blended, ionic impurities increase, and the reliability of the semiconductor device may be impaired. For this reason, it is preferable to blend an inorganic ion scavenger (synthetic hydrotalcite) represented by the following formula 5 into such an epoxy resin composition. The mixing ratio of the inorganic ion scavenger is usually from 0.1 to 30 parts by weight, preferably from 1 to 5 parts by weight, based on 100 parts by weight of the total epoxy resin. Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3.5H ₂ O As the inorganic filler of the formula 5 (D) component, for example, fused silica powder, crystalline silica powder, alumina, aluminum nitride, silicon nitride and the like are used. . As the shape, a spherical shape, an irregular shape, an elliptical shape, or the like is used. The mixing ratio is 60 to 95% by weight based on the total amount of the epoxy resin composition. If it is less than 60% by weight, sufficient reflow crack resistance cannot be maintained, and if it exceeds 95% by weight, sufficient fluidity for molding cannot be maintained. Further, the epoxy resin composition used in the present invention may optionally contain a pigment such as carbon black, a coupling agent such as a silane coupling agent, and additives such as silicone.

The above-mentioned raw materials are appropriately blended, and the blends are kneaded in a kneading machine such as a mixing roll machine to form a semi-molten resin composition, which is cooled to room temperature and pulverized by a known means. The desired epoxy resin composition for encapsulating a semiconductor can be obtained through a series of steps of tableting as required. The epoxy resin composition for semiconductor encapsulation of the present invention is usually used for encapsulating semiconductors as a powder or as a material for tablet tablets obtained by compressing it.
When a semiconductor element is sealed using the epoxy resin composition of the present invention, a target semiconductor device is obtained. The method for encapsulating the semiconductor element is not particularly limited, and a normal method,
For example, it can be performed by a known molding method such as transfer molding. The semiconductor device obtained in this way has excellent adhesiveness between the insert and the sealing material, has a small amount of moisture absorption into the sealing material, and has excellent crack resistance when soldering the device to a substrate, It has excellent sealing workability without sticking to the mold side when transfer molding a semiconductor device.

[0011]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to these examples. First, after mixing and pre-mixing each material in parts by weight shown in Tables 1 and 2, using a biaxial roll having a diameter of 10 inches, at a kneading temperature of 80 to 90 ° C. and a kneading time of 7 to 12 minutes. Then, the mixture was cooled and pulverized to obtain an epoxy resin composition for semiconductor encapsulation. Using the epoxy resin composition for sealing, a transfer molding machine was used to mold at a mold temperature of 180 ° C., a molding pressure of 70 kgf / cm ² , and a curing time of 90 seconds to prepare a test piece. Post cure 175
C. for 6 hours. Spiral flow is EMMI1-
66 was measured. The hardness at the time of heating measured the Shore hardness of the molded article molded under the above conditions. The adhesive strength of the Al peel is a width of 1 on an aluminum foil with a thickness of about 0.03 mm.
It was measured on a 0 mm molded product. The water absorption was determined by molding a disk of φ50 × 3 mmt under the above molding conditions and determining the water absorption after 20 hours of PCT. Reflow crack resistance is QFP14 × 2
After molding under the above conditions using a package of 0 × 2.0 mmt, and left in an atmosphere of 85 ° C./85 RH% for X hours,
Heating in IR reflow furnace (furnace temperature: MAX 245 ° C)
Then, the presence or absence of cracks was observed with an ultrasonic microscope. Table 1
And B / A in Table 2, A indicates the number of packages subjected to the test, and B indicates the number of packages in which cracks were observed. The releasability was determined by continuously forming a molded product of 20 mmφ on the surface of the Cr-plated stainless steel plate, and changing the shear adhesive force between the metal plate and the sealing material. ◎ indicates 0 kgf within 5 shots, ○ indicates 0 kgf within 5 to 10 shots, and x indicates 0 kgf after molding 10 shots. In Table 2, high temperature storage (175 ° C.)
This represents the time when the package was left at 175 ° C. and the device became defective. Table 1 shows Examples 1 to 4 and Comparative Example 1.
The results of No. to No. 4 are shown. Table 2 shows Examples 5 and 6 and Comparative Examples 5
6 shows the results. As can be seen from these results, the epoxy resin composition for semiconductor encapsulation of the present invention is excellent in reflow crack resistance, high-temperature storage properties, mold release properties, and the like.

[0012]

[Table 1] Other Compositions (Common to Examples and Comparative Examples) Silane coupling agent 6 parts Carnauba wax 2 parts Antimony trioxide 15 parts Carbon black 2 parts The epoxy resin of structural formula 1 is ZX manufactured by Meiwa Kasei Co., Ltd. having an epoxy equivalent of 257. -1257 (trade name) was used as the epoxy resin of structural formula 3 with an epoxy equivalent of about 192.
YX-4000H (trade name) manufactured by Yuka Shell Co., Ltd .; orthocresol novolak (OCN); ESCN-195 (trade name) manufactured by Sumitomo Chemical Co., Ltd. having an epoxy equivalent of about 200; About 3
75, ESB-4 manufactured by Sumitomo Chemical Co., Ltd. containing about 50% by weight of bromine
00T (trade name) was used. As a phenol novolak resin as a curing agent, HP-850N (trade name) manufactured by Hitachi Chemical Co., Ltd. having a hydroxyl equivalent of about 106 was used.

[0013]

[Table 2] Oxidation 15-30 mg KOH / g, number average molecular weight about 200
Branched polyethylene wax of 0 Other composition (common to Examples and Comparative Examples) Silane coupling agent 6 parts Antimony trioxide 15 parts Carbon black 2 parts

[0014]

The epoxy resin composition for semiconductor encapsulation of the present invention has excellent heat resistance during soldering, and other excellent reliability and moldability. Therefore, the epoxy resin composition for encapsulation with the encapsulation resin composition. The resulting semiconductor device also has excellent heat resistance and other reliability during soldering.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 3/22 C08K 3/22 3/26 3/26 5/524 5/524 H01L 23/29 H01L 23/30 R 23/31 // (C08L 63/00 23:00) (72) Inventor Terumi Tsukahara 172-1, Okakabo, Yuki-shi, Ibaraki Hitachi Chemical Co., Ltd. Shimodate Plant (72) Inventor Masanobu Fujii 1772- Okakabo, Yuki-shi, Ibaraki 1 Hitachi Chemical Industries Co., Ltd. Shimodate Plant (72) Inventor Hiroki Yukishima 172-1 Okakubo, Yuki City, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Shimodate Plant

Claims (7)

[Claims] An epoxy resin composition for semiconductor encapsulation comprising the following components (A) to (D): (A) an epoxy resin containing 70% by weight or more of an epoxy resin represented by the following structural formula 1: (B) a compound having two or more phenolic hydroxyl groups in one molecule; (C) a phosphorus compound represented by the following structural formula 2: And (D) 60 to 95% by weight based on the total amount of the epoxy resin composition
Inorganic filler. 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the component (A) is an epoxy resin containing 2 to 30% by weight of an epoxy resin represented by the following structural formula 3. Embedded image (In the formula, R represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms, and m represents an integer of 0 to 6.) 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the component (B) is a compound represented by the following structural formula 4. Embedded image (In the formula, p represents an integer of 0 to 6.) 4. An oxidized or non-oxidized polyolefin is added to 100 parts by weight of the total epoxy resin as the component (A).
The epoxy resin composition for semiconductor encapsulation according to claim 1, which contains 0.01 to 10 parts by weight. 5. The epoxy resin composition for semiconductor encapsulation according to claim 1, which comprises a brominated epoxy resin or antimony trioxide as a flame retardant. 6. The epoxy resin composition for semiconductor encapsulation according to claim 1, further comprising an inorganic ion scavenger represented by the following formula (5). Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3.5H ₂ O Formula 5 7. A resin-encapsulated semiconductor device, which is encapsulated with the epoxy resin composition for encapsulating a semiconductor according to any one of claims 1 to 6.