JP2006104393A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition high in adhesive strength to lead frame and excellent in reliability after undergoing soldering treatment, and to provide a semiconductor device. <P>SOLUTION: The epoxy resin composition for semiconductor sealing use comprises (A) an epoxy resin, (B) a phenolic resin, (C) a curing promoter, (D) an inorganic filler, (E) a compound having a triazine thiol structure and represented by the general formula(1) and (F) an aromatic carboxylic acid. The semiconductor device obtained by sealing semiconductor elements with this resin composition is also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an epoxy resin composition for semiconductor encapsulation and a semiconductor device using the same.

  In recent years, semiconductor devices have been mainly sealed using an epoxy resin composition because of excellent balance of productivity, cost, reliability, and the like. Due to the surface mounting of the semiconductor device, the semiconductor device is suddenly exposed to a high temperature of 200 ° C. or higher in the solder dipping or solder reflow process, and the stress generated when the absorbed water vaporizes explosively causes the semiconductor element, lead frame, inner lead. There is a problem that peeling occurs at the interface between each of the above-mentioned various plated joint portions and the cured product of the epoxy resin composition, or cracks are generated in the semiconductor device and the reliability is remarkably lowered.

In order to improve reliability reduction due to solder processing, increase the amount of inorganic filler in the epoxy resin composition to achieve low moisture absorption, high strength, low thermal expansion, and improve solder resistance. A technique of maintaining low fluidity and high fluidity during molding using a low melt viscosity resin is becoming common.
On the other hand, in terms of reliability after soldering, the adhesiveness at the interface between a cured product of the epoxy resin composition and a substrate such as a semiconductor element or a lead frame existing inside the semiconductor device has become very important. If the adhesive force at the interface is weak, peeling occurs at the interface with the base material after the solder treatment, and further, cracks occur in the semiconductor device due to this peeling.
Conventionally, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane and γ- (methacryloxypropyl) trimethoxysilane have been added to epoxy resin compositions for the purpose of improving solder resistance. However, in recent years, in response to the increasingly demanding soldering resistance, such as an increase in reflow temperature during mounting and the appearance of pre-plating frames such as Ni-Pd and Ni-Pd-Au in correspondence with lead-free solder, These silane coupling agents alone are not sufficient.

As a countermeasure, a lead frame surface treatment with an alkoxysilane coupling agent (see, for example, Patent Document 1), a resin composition to which a triazine compound is added, and a resin-encapsulated semiconductor device (for example, Patent Document 2). And Patent Document 3). However, the former silane coupling agent has a drawback that the stability during heat is poor and the effect of improving adhesion in the solder-resistant treatment is lowered, and the latter compound has low reactivity with the resin, so that it serves as an adhesion imparting agent. I knew it was less effective.
In recent years, a method for improving the adhesion with a copper alloy lead frame or the like by containing a cyclic nitrogen compound has been proposed (for example, see Patent Document 4). It has been found that the effect of improving the adhesion with a pre-plating frame such as -Pd or Ni-Pd-Au is scarce and further improvement is necessary.

JP-A-6-350,000 (pages 2 to 5) JP-A-62-209170 (pages 2 to 4) Japanese Unexamined Patent Publication No. 2003-160643 (pages 2 to 4) JP 2001-106768 A (pages 2 to 6)

  The present invention provides an epoxy resin composition excellent in reliability after soldering and a semiconductor device that does not peel off from a lead frame during soldering.

The present invention
[1] (A) Epoxy resin, (B) Phenolic resin, (C) Curing accelerator, (D) Inorganic filler, (E) Compound represented by general formula (1), and (F) Aromatic carvone An epoxy resin composition for semiconductor encapsulation, comprising an acid,

（式中、Ｒ１、Ｒ２は炭素数１〜３のアルキル基であり、互いに同一でも異なっていてもよい。）

(In the formula, R1 and R2 are alkyl groups having 1 to 3 carbon atoms, which may be the same as or different from each other.)

[2] The epoxy resin composition for semiconductor encapsulation according to item [1], wherein the compound represented by the general formula (1) is 2-di-propylamino-4,6-dimercapto-s-triazine,
[3] The semiconductor encapsulation according to [1] or [2], wherein the compound represented by the general formula (1) is contained in a proportion of 0.004 to 2% by weight with respect to the entire resin composition. Epoxy resin composition for
[4] The semiconductor according to any one of [1], [2] or [3], wherein the aromatic carboxylic acid is contained in a proportion of 0.004 to 2% by weight based on the entire resin composition. Epoxy resin composition for sealing,
[5] The first [1], [2], [3], wherein the aromatic carboxylic acid is a compound having at least two phenolic hydroxyl groups per molecule and at least one carboxyl group per molecule. Or the epoxy resin composition for semiconductor encapsulation according to any one of [4],
[6] A semiconductor device comprising a semiconductor element sealed with the epoxy resin composition according to any one of [1], [2], [3], [4], and [5]. ,
It is.

  The semiconductor device obtained by using the epoxy resin composition of the present invention has high adhesion strength with various lead frames including those plated with Ni, Ni-Pd, Ni-Pd-Au, etc. Excellent in reliability.

The present invention includes an epoxy resin, a phenol resin, a curing accelerator, an inorganic filler, a compound having a triazine thiol structure such as 2-di-propylamino-4, 6-dimercapto-s-triazine, and an aromatic carboxylic acid. Thus, it is possible to obtain an epoxy resin composition for semiconductor encapsulation excellent in reliability after solder processing, in which peeling from the lead frame does not occur during solder processing.
Hereinafter, the present invention will be described in detail.

  The epoxy resins used in the present invention are monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule, and the molecular weight and molecular structure are not particularly limited. For example, hydroquinone type epoxy resins Bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, stilbene type epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy resin, naphthol novolak type epoxy resin, triphenolmethane type epoxy resin, alkyl modified Triphenolmethane type epoxy resin, dicyclopentadiene modified phenol type epoxy resin, phenol aralkyl type epoxy resin (having phenylene skeleton, biphenylene skeleton, etc.), naphthol aralkyl type epoxy resin Carboxymethyl resin (phenylene skeleton, a biphenylene skeleton, etc.), terpene-modified phenol type epoxy resins, triazine nucleus-containing epoxy resins. These epoxy resins may be used alone or in combination.

Examples of the phenol resin used in the present invention include monomers, oligomers, and polymers in general having two or more phenolic hydroxyl groups in one molecule, and the molecular weight and molecular structure thereof are not particularly limited. Resin, cresol novolak resin, phenol aralkyl resin (having phenylene skeleton, biphenylene skeleton, etc.), naphthol aralkyl resin (having phenylene skeleton, biphenylene skeleton, etc.), terpene modified phenol resin, dicyclopentadiene modified phenol resin, triphenolmethane type A phenol resin, a bisphenol compound, etc. are mentioned. These phenol resins may be used alone or in combination of two or more.
The equivalent ratio of epoxy groups of all epoxy resins to phenolic hydroxyl groups of all phenol resins is preferably 0.5 to 2.0, particularly preferably 0.7 to 1.5. If it is out of the above range, curability, moisture resistance reliability and the like may be lowered.

  The curing accelerator used in the present invention is not particularly limited as long as it can serve as a catalyst for a crosslinking reaction between an epoxy resin and a phenol resin, and those generally used for a sealing material can be used. For example, amine compounds such as tributylamine, 1,8-diazabicyclo (5,4,0) undecene-7, organic phosphorus compounds such as triphenylphosphine, tetraphenylphosphonium tetraphenylborate salts, 2-methylimidazole, etc. However, it is not limited to these. These curing accelerators may be used alone or in combination.

As the inorganic filler used in the present invention, those generally used for epoxy resin compositions for semiconductor encapsulation can be used, and examples thereof include fused silica, crystalline silica, alumina, silicon nitride, aluminum nitride and the like. It is done. These inorganic fillers may be used alone or in combination.
When increasing the content of the inorganic filler, it is common to use fused silica. The fused silica can be used in either crushed or spherical shape, but in order to increase the content of fused silica and to suppress the increase in the melt viscosity of the epoxy resin composition, it is better to mainly use the spherical one. preferable. Furthermore, in order to increase the blending amount of the fused spherical silica, it is desirable to adjust so that the particle size distribution of the fused spherical silica becomes wider. The inorganic filler that has been surface-treated with a silane coupling agent or the like in advance may be used. Although content of an inorganic filler is not specifically limited, 65 to 90 weight% is preferable in all the epoxy resin compositions. If the lower limit is not reached, sufficient solder resistance may not be obtained, and if the upper limit is exceeded, sufficient fluidity may not be obtained.

（式中、Ｒ１、Ｒ２は炭素数１〜３のアルキル基であり、互いに同一でも異なっていてもよい。） The compound represented by the general formula (1) and the aromatic carboxylic acid used in the present invention improve the adhesion between the cured product of the resin composition and the lead frame. It plays the role of improving the moisture resistance reliability and reflow crack resistance of the sealed semiconductor device.

(In the formula, R1 and R2 are alkyl groups having 1 to 3 carbon atoms, which may be the same as or different from each other.)

  R1 and R2 in the compound represented by the general formula (1) are alkyl groups having 1 to 3 carbon atoms, and may be the same as or different from each other. If the number of carbon atoms in the alkyl group exceeds the upper limit, steric hindrance due to the substituted alkyl group is increased, so that the adhesion to the lead frame is lowered and the reliability as a semiconductor device is also lowered. As an example of the compound represented by the general formula (1), 2-dipropylamino-4,6-dimercapto-s-triazine represented by the formula (2) can be preferably used.

  Although the compounding quantity of the compound represented by General formula (1) is not specifically limited, It is preferable that it is 0.004 to 2 weight% with respect to the whole resin composition. Below the lower limit, the effect of improving the adhesion between the cured product of the resin composition and the lead frame becomes insufficient, and consequently the moisture resistance of the semiconductor device formed by sealing the semiconductor element with the cured product of the resin composition. This is not preferable because the effect of improving the reliability and reflow crack resistance may be insufficient. Moreover, when the above upper limit is exceeded, the fluidity of the resin composition may be lowered, which is not preferable.

Although it does not specifically limit as a compounding quantity of the aromatic carboxylic acid used by this invention, It is preferable to contain in the ratio of 0.004 to 2 weight% with respect to all the epoxy resin compositions. Below the lower limit, the effect of improving the adhesion between the cured product of the resin composition and the lead frame may be insufficient, which is not preferable. On the other hand, when the above upper limit is exceeded, the fluidity of the resin composition may be lowered, which is not preferable.
The aromatic carboxylic acid used in the present invention is not particularly limited in molecular structure, but a compound having at least two phenolic hydroxyl groups per molecule and at least one carboxyl group per molecule, It is more preferable from the viewpoint of improving adhesion. Examples of the compound having at least two phenolic hydroxyl groups per molecule and at least one carboxyl group per molecule include compounds represented by the following general formulas (3) and (4). be able to.

  The epoxy resin composition of the present invention includes an epoxy resin, a phenol resin, a curing accelerator, an inorganic filler, a compound represented by the general formula (1), and an aromatic carboxylic acid, and if necessary, a silane coupling. Agent, titanate coupling agent, aluminum coupling agent, coupling agent such as aluminum / zirconium coupling agent, flame retardant such as brominated epoxy resin, antimony oxide, phosphorus compound, inorganic ion exchanger such as bismuth oxide hydrate , Colorants such as carbon black and bengara, low stress agents such as silicone oil and silicone rubber, natural wax, synthetic wax, release agents such as higher fatty acids and their metal salts or paraffin, and various additives such as antioxidants May be appropriately blended.

The epoxy resin composition of the present invention contains an epoxy resin, a phenol resin, a curing accelerator, an inorganic filler, a compound represented by the general formula (1), an aromatic carboxylic acid, and other additives using a mixer. After mixing, the mixture is obtained by kneading with a kneader such as a roll, a kneader or an extruder, and pulverizing after cooling.
In order to seal an electronic component such as a semiconductor element and manufacture a semiconductor device using the epoxy resin composition of the present invention, it may be cured by a molding method such as a transfer mold, a compression mold, or an injection mold.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these. The blending unit is parts by weight.
Example 1

Epoxy resin 1: epoxy resin represented by formula (5) (softening point: 58 ° C., epoxy equivalent: 272) 8.2 parts by weight

Phenol resin 1: phenol resin represented by the formula (6) (softening point 107 ° C., hydroxyl group equivalent 200) 6.0 parts by weight

1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU)
0.2 part by weight Fused spherical silica (average particle size 28 μm) 84.9 parts by weight

2-dipropylamino-4,6-dimercapto-s-triazine (reagent) represented by the formula (2) 0.1 part by weight

0.1 part by weight of 2,5-dihydroxybenzoic acid represented by the formula (7)

Carnauba wax 0.2 parts by weight Carbon black 0.3 parts by weight was mixed using a mixer, then kneaded using two rolls with surface temperatures of 90 ° C. and 25 ° C., cooled and pulverized to obtain an epoxy resin composition. Got. The characteristics of the obtained epoxy resin composition were evaluated by the following methods. The results are shown in Table 1.

Evaluation method Spiral flow: Using a mold for spiral flow measurement according to EMMI-1-66, measurement was performed under conditions of a mold temperature of 175 ° C., an injection pressure of 6.9 MPa, and a curing time of 120 seconds. The unit is cm.

Adhesion strength: 2 mm x 2 mm x 2 mm adhesion on a 9 x 29 mm strip test lead frame using a transfer molding machine under conditions of a mold temperature of 175 ° C, an injection pressure of 9.8 MPa, and a curing time of 120 seconds Ten strength test pieces were molded per level. Two types of lead frames were used: a silver plated copper frame (frame 1) and a gold plated NiPd alloy frame (frame 2). Then, the shear strength of the cured product of the epoxy resin composition and the lead frame was measured using an automatic shear strength measuring device (manufactured by DAGE, PC2400). Table 1 shows the average value of the shear strength of 10 test pieces. The unit is N / mm ² .

  Solder resistance: 176-pin LQFP package (package size is 24 x 24 mm, thickness is 2.0 mm, silicon chip size is 8.0 x 8.0 mm, lead frame is 176 pin pre-plating frame, NiPd alloy is Au plated Was molded by transfer molding under conditions of a mold temperature of 175 ° C., an injection pressure of 9.3 MPa, and a curing time of 120 seconds, and post-cured at 175 ° C. for 8 hours. The resulting package was humidified for 168 hours in an environment of 85 ° C. and a relative humidity of 60%. Thereafter, this package was immersed in a solder bath at 260 ° C. for 10 seconds. The soldered package was observed using an ultrasonic flaw detector, and the occurrence rate of peeling at the interface between the chip (SiN coated product) and the cured epoxy resin composition [(number of peeling occurrence packages) / (Total number of packages) × 100] is displayed in%.

Examples 2-7, Comparative Examples 1-3
According to the composition of Table 1, an epoxy resin composition was obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. These results are shown in Table 1. The details of the epoxy resin and phenol resin used are shown in Table 2.
Moreover, it shows below about the other component used except Example 1. FIG.

2-Dimethylamino-4,6-dimercapto-s-triazine represented by the formula (8)

4 ′, 4 ″ -dihydroxytriphenylmethane-2-carboxylic acid represented by the formula (9)

γ-Glycidoxypropyltrimethoxysilane An epoxy resin composition to which 2-dipropylamino-4,6-dimercapto-s-triazine and 2,5-dihydroxybenzoic acid of Example are added has an adhesion strength with a lead frame. As a result, the results were high and the solder resistance was excellent. Moreover, as shown in Example 2, even if the type of resin is changed, high adhesion strength and excellent performance can be obtained by adding 2-dipropylamino-4,6-dimercapto-s-triazine and 2,5-dihydroxybenzoic acid. Solder resistance was obtained. In Examples 3 and 4, the addition amounts of 2-dipropylamino-4,6-dimercapto-s-triazine and 2,5-dihydroxybenzoic acid were changed. Adhesion strength and solder resistance were obtained. Further, Example 5 uses 4 ′, 4 ″ -dihydroxytriphenylmethane-2-carboxylic acid in place of 2,5-dihydroxybenzoic acid in Example 1, but the same degree as in Example 1. Adhesive strength and solder resistance were obtained, and in Example 6, instead of 2-dipropylamino-4,6-dimercapto-s-triazine in Example 1, 2-dimethylamino-4,6-dimercapto- Although s-triazine was used, in this case as well, adhesion strength and solder resistance comparable to those of Example 1 were obtained.

  Although Comparative Example 1 is a system in which no aromatic carboxylic acid is added, the adhesion strength is moderately high, but the results are poor in solder resistance. Comparative Example 2 is a system in which a compound having a triazine thiol structure represented by the formula (1) is not added, but although the adhesion strength is moderately high, the result of inferior solder resistance was obtained. Comparative Example 3 uses γ-glycidoxypropyltrimethoxysilane, which has been conventionally used as an additive for improving solder resistance. The results of adhesion strength and solder resistance are expressed by equations. The result clearly inferior to Examples 1-5 which added the compound which has a triazine thiol structure represented by (1), and aromatic carboxylic acid was obtained.

  Since the semiconductor device obtained using the epoxy resin composition of the present invention has high adhesion strength with the lead frame and is excellent in reliability after soldering, the epoxy resin composition of the present invention is a variety of resins. It can be widely used for sealed semiconductor devices. In particular, it improves the adhesion between the cured resin composition and the plated copper lead frame (silver plated lead frame, nickel plated lead frame, nickel / palladium alloy gold preplated frame, etc.). Since the effect is remarkable, it can be suitably used for a semiconductor device using a plated lead frame.

Claims (6)

Including (A) epoxy resin, (B) phenol resin, (C) curing accelerator, (D) inorganic filler, (E) compound represented by general formula (1), and (F) aromatic carboxylic acid An epoxy resin composition for semiconductor encapsulation characterized by the above-mentioned.

(In the formula, R1 and R2 are alkyl groups having 1 to 3 carbon atoms, which may be the same as or different from each other.) The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the compound represented by the general formula (1) is 2-di-propylamino-4,6-dimercapto-s-triazine. The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2, wherein the compound represented by the general formula (1) is contained in a proportion of 0.004 to 2% by weight with respect to the entire resin composition. 4. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the aromatic carboxylic acid is contained in a proportion of 0.004 to 2% by weight with respect to the entire resin composition. 5. The compound according to claim 1, wherein the aromatic carboxylic acid is a compound having at least two phenolic hydroxyl groups per molecule and at least one carboxyl group per molecule. Epoxy resin composition for semiconductor encapsulation. A semiconductor device comprising a semiconductor element sealed with the epoxy resin composition according to claim 1.