JPH09124901A - Epoxy resin composition for semiconductor sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for semiconductor sealing, which can give a cured product having good adhesion to various metallic materials and various organic substrates and improved in soldering resistance by using a crystalline epoxy resin, a specified flexible curing agent, a cure accelerator, an inorganic filler, a specified silane coupling agent and a specified mold release as the essential components. SOLUTION: This resin composition essentially consists of a crystalline epoxy resin of a melting point of 50-150 deg.C, a flexible curing agent represented by formula I; a cure accelerator, 75-92wt.%, based on the entire composition, inorganic filler, a double-bond-containing silane coupling agent represented by formula II (wherein R<1> is H or CH3 , R<2> is a group of formula V or null; and A is CH3 or C2 H5 ), and mold releases represented by formulas III (wherein R<3> is a 17C or higher alkyl) and/or formula IV (wherein R<4> is a 17C or higher alkyl; and R<5> is CH2 , C2 H4 , or the like).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to various metallic materials (4
2 alloys, copper, silicon, silver, gold) and organic base materials, especially polyimide and polymethylmethacrylate (hereinafter PMMA).
The present invention relates to an epoxy resin composition for semiconductor encapsulation, which has excellent moisture resistance reliability such as solder crack resistance and good moldability because it has excellent void resistance.

[0002]

2. Description of the Related Art Epoxy resin compositions have been developed and produced in order to protect IC bodies from mechanical and chemical effects. Items required for this change depending on the structure of the sealed IC package. Due to the trend toward lightness, thinness, shortness, and high pin count, the package structure is changing in a variety of ways. A list of various base materials that exist in the internal structure of the package is as follows: 42 alloy as a base material of the lead frame, copper, gold and silver as a base material necessary for assembly, aluminum and silicon as a base material of the chip. , Silicon nitride,
Silicon, polyimide as other organic constituent material,
It covers a wide range of areas such as PMMA. These materials and the encapsulating resin composition must exhibit good adhesion. However, the conventional methods for imparting adhesion have not been sufficient to improve the adhesion to these organic substrates. A method often used to improve adhesion is to add a coupling agent to the encapsulating resin composition. For example, Japanese Patent Publication No. 59-43
According to Japanese Patent Laid-Open No. 062, when an epoxy silane coupling agent and a mercapto silane coupling agent are used in combination, the adhesion to various substrates is improved and the moisture resistance reliability is also improved.

However, these coupling agents improve the adhesion to some metals, but have no effect on the adhesion to other metals and organic substrates. Although various attempts have been made to improve adhesion to these organic substrates,
No effective means has been found yet. However, these methods improve only a small part of the above-mentioned substrate, and a method capable of improving all of them has not been found.

[0004]

The present invention has good adhesion to various metal materials and organic substrates, improved solder resistance, improved voidability and curability, and good moldability. An epoxy resin composition for semiconductor encapsulation is provided.

[0005]

According to the present invention, (A) a melting point of 5
Crystalline epoxy resin at 0 to 150 ° C., (B) flexible curing agent represented by the formula (1), (C) curing accelerator, (D) inorganic composition in an amount of 75 to 92% by weight in the total composition. Material, (E) a silane coupling agent containing an unsaturated double bond represented by formula (2), and (F) a mold release agent of formula (3) and / or formula (4) as a semiconductor encapsulation which is an essential component It is an epoxy resin composition for use.

[0006]

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[0007]

[Chemical 6]

[0008]

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[0009]

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[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention is a crystalline epoxy resin having a melting point of 50 to 150 ° C.
A crystalline epoxy resin is an epoxy compound that has a low molecular weight and a planar structure skeleton in terms of molecular structure, and is a crystalline solid that is crystallized at room temperature. Then melts rapidly and has a low viscosity (0.
It changes to a liquid around 1 to 10 poises). When measuring the melting behavior with a differential scanning calorimeter, the crystalline epoxy resin develops a sharp melting peak. The melting point of the crystalline epoxy resin is 50 to 150 ° C. If it is lower than 50 ° C., the crystalline epoxy resin is melted at room temperature, and there is a concern that workability may be deteriorated and the room temperature storage property of the resin composition may be deteriorated. If it exceeds 150 ° C, it will not melt sufficiently during kneading, and it will not be possible to uniformly disperse, so the curability will decrease and the moldability will decrease, resulting in a non-uniform molded product, and the strength of each part will vary and the performance of the semiconductor package will decrease. To do. Examples of epoxy resins that satisfy these conditions include bisphenol A type epoxy resins, bisphenol F type epoxy resins, and naphthalene type epoxy resins. Chloride ion, sodium ion contained in these epoxy resins for improving moisture resistance reliability,
It is desirable that the number of other free ions is as small as possible. The epoxy equivalent is preferably 100 to 350. 100
If it is less than the above range, the number of reaction points increases, so that the water absorption rate of the resin composition becomes high and the solder crack resistance is deteriorated. 35
If it exceeds 0, the reactivity decreases and the moldability deteriorates.

The hardener used in the present invention is a flexible hardener represented by the formula (1). It has been found that this flexible curing agent significantly lowers the water absorption of the molded product as compared with the conventional phenol novolac resin curing agent and improves the solder crack resistance of the molded product. The molecular weight and the like are not particularly limited. Further, there is no problem even if this curing agent is modified with silicone. Furthermore, in order to improve the reliability of humidity resistance, it is desirable that chlorine ions, sodium ions, and other free ions contained as impurities are minimized. The content of the inorganic filler is preferably 75 to 92% by weight based on the total resin composition. If it is less than 75% by weight, the water absorption of the resin becomes high and the solder crack resistance is lowered. If it exceeds 92% by weight, the melt viscosity of the resin composition becomes too high and molding cannot be performed even if a spherical filler is used.

The inorganic filler used in the present invention includes:
Fused silica powder, spherical silica powder, crystalline silica powder, 2
Examples of the secondary agglomerated silica powder, alumina and the like are preferable, and spherical silica powder is particularly preferable from the viewpoint of improving the fluidity of the encapsulating resin composition. For the shape of the spherical silica powder, it is desirable that the shape of the particles themselves be infinitely spherical in order to improve the fluidity, and further that the particle size distribution is broad. Further, in order to improve the moisture resistance, it is desired that ionic impurities such as alkali metals, alkaline earth metals and halogens are not included as much as possible. The inorganic filler may be surface-treated in advance with an unsaturated double bond-containing silane coupling agent, another silane-based agent, a titanium-based agent, or another surface-treating agent without causing any problems. The curing accelerator used in the present invention is not particularly limited as long as it accelerates the chemical reaction between the epoxy group and the phenolic hydroxyl group. Commonly used ones include triphenylphosphine, 1,8-diazabicyclo (5,4,0) undecene-7, tetraphenylphosphonium tetraborate salt, 2-methylimidazole and the like. In order to improve the moisture resistance of the resin composition, it is desirable that the ionic impurities are as low as possible. Further, a curing accelerator that acts as a latent catalyst is more preferable.

The unsaturated double bond-containing silane coupling agent of the formula (2) used in the present invention is a technically important point of the present invention and will be described in detail below. C = in the molecule
Due to the presence of the C-bond, this coupling agent has a chemical affinity for the organic constituent materials inside the package. In particular, a large amount of C═C bonds remaining on the surface chemically reacts with the surface, and strong interfacial adhesion can be exhibited by the chemical bonds. In particular, it has been found that the use of this silane coupling agent improves the adhesion to general metals. Of course, the C = C bond is not reactive with the metal, and the silane coupling agent having this group was not considered to be effective in improving the adhesion to the metal. However, experiments have shown that it has a great effect on improving the adhesion to general metals. In addition, it was surprisingly found that it exhibits good adhesion to stable metals with extremely low reactivity such as gold and silver, which have been extremely difficult to adhere to. It is not clear whether the adhesion with metal is improved by blending this silane coupling agent, but it is presumed that this is because the hydrophilicity and the hydrophobicity are balanced. C
A silane coupling agent having a ═C bond can improve adhesion to a metal or an organic constituent material by dispersing it in a resin composition, but also by pretreating the surface of an inorganic filler such as silica. Effective in improving adhesion. The coupling agent of the present invention can be used in combination with other types of coupling agents in order to balance with other performance requirements. The silane coupling agent of the present invention is preferably 20% by weight or more based on all coupling agents. If it is less than 20% by weight, good adhesion cannot be obtained.

The release agent used in the present invention is represented by the formula (3) and the formula (4). In the present invention, since the silane coupling agent of the formula (2) is used to improve the adhesion to each substrate, the releasability is remarkably reduced. The formulas (3) and (4) are effective in improving the releasability and do not cause a decrease in adhesion. This mold release agent is composed of a hydrophobic group portion of an alkyl group, a -COO- bond or a -NHCO
The hydrophilic / hydrophobic balance with the hydrophilic group part of the bond is well balanced and the resin composition bleeds out appropriately, which is ideal for improving the releasability, and the adhesiveness of the formula (2) It has been found that when used in combination with a good coupling agent, a very excellent effect is exhibited.

In addition to the above-mentioned raw materials, the composition of the present invention may optionally contain a coloring agent such as carbon black, a brominated epoxy resin, a flame retardant such as antimony trioxide, a low stress component such as silicone oil and rubber. can do. The epoxy resin composition of the present invention is an epoxy resin, a flexible curing agent, an inorganic filler, a curing accelerator, a silane coupling agent,
A mold release agent and other additives may be mixed at room temperature with a mixer, kneaded with a general kneader such as a roll or an extruder, cooled, and then pulverized to obtain a molding material.

The present invention will be specifically described below with reference to examples. Example 1 Epoxy resin (E-1) 8.45 parts by weight Paraxylylene-modified phenol novolac resin curing agent (H-1) 8.25 parts by weight Spherical silica (average particle size 15 μm) 80.0 parts by weight 1,8-diazabicyclo (5,4,0) Undecene-7 (DBU) 0.2 parts by weight carbon black 0.3 parts by weight Release agent (R-1) 0.3 parts by weight Brominated phenol novolac type epoxy resin 1.0 parts by weight 1.0 part by weight of antimony trioxide and 0.5 part by weight of a silane coupling agent (S-1) were mixed at room temperature with a mixer, kneaded with a biaxial roll at 100 ° C., cooled and pulverized to obtain a molding material. The adhesion of the obtained molding material to various substrates, solder crack resistance, fluidity, and mold fouling were evaluated.

Evaluation Method Adhesion to Substrate: A molded product shown in FIG. 1 is molded. Molding was performed at a mold temperature of 175 ° C. for a molding time of 2 minutes, and after that, post-curing was performed at 175 ° C. for 8 hours, and then evaluated by a tensile tester as shown in FIG. The evaluated base materials were those of 42 alloy, copper, and 42 alloy coated with a solder resist containing polymethylmethacrylate as a main component. The unit is kgf / mm ² . Solder crack resistance: 80 pQFP (thickness 2 mm, chip size 9 mm × 9 mm) is molded. Molding temperature 175
℃, curing time 2 minutes, post cure 175 ℃, 8 hours.
After treating eight packages at 85 ° C. and 85% relative humidity for 72 hours, IR reflow treatment (240 ° C.) is performed. The state of internal peeling and cracking after the treatment was observed with an ultrasonic flaw detector, and the number of defective packages was counted. Spiral flow: Measured at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² , and a curing time of 2 minutes using a mold for spiral flow measurement according to EMMI-I-66. The unit is cm. Mold stain: When 80 pQFP was molded, the surface condition of the molded product was visually observed. ○ If the molded product is clean,
If there is, it is marked as x.

Examples 2 to 12 Compounds were prepared according to the formulations shown in Tables 1 and 2, and molding materials were obtained in the same manner as in Example 1 and evaluated in the same manner. The treated silica A used in Example 9 was spherical silica (average particle size 15 μm).
80.0 parts by weight and silane coupling agent (S-1)
After mixing 0.5 parts by weight with a high speed mixer, 125
Treated at ℃ for 10 hours. The treated silica B used in Example 10 is treated with 80.0 parts by weight of spherical silica (average particle size 15 μm) and 0.5 parts by weight of the silane coupling agent (S-2) under the same conditions as above. Comparative Examples 1 to 7 Compounding was performed according to the formulation shown in Table 3, molding materials were obtained in the same manner as in Example 1, and evaluated in the same manner. The materials used in Examples and Comparative Examples are as follows.

[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

EFFECTS OF THE INVENTION According to the present invention, it adheres well to various metals and organic base materials, and also exhibits good adhesion to a package having a complicated shape having various base materials. A good semiconductor package with excellent strength can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of a molded article obtained by integrally molding a base material and a sealing material.

FIG. 2 is a schematic diagram showing a tensile test of a molded product.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 5/17 NLB C08K 5/17 NLB 5/54 NLC 5/54 NLC H01L 23/29 H01L 23 / 30 R 23/31

Claims (1)

[Claims] 1. A crystalline epoxy resin having a melting point of 50 to 150 ° C., (B) a flexible curing agent represented by the formula (1), and (C).
Curing accelerator, (D) Inorganic filler contained in the total composition in an amount of 75 to 92% by weight, (E) Unsaturated double bond-containing silane coupling agent represented by formula (2), and formula (F) An epoxy resin composition for semiconductor encapsulation, which comprises (3) and / or a release agent of the formula (4) as an essential component. Embedded image Embedded image Embedded image Embedded image