JPH09221580A - Epoxy resin composition for semiconductor sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-performance resin composition excellent in adhesion and soldering resistance by using an epoxy resin, a phenolic resin curing agent, a cure accelerator, an inorganic filler and a reaction product of a specified aminosilane coupling agent with an acid anhydride as the essential components. SOLUTION: This composition essentially consists of an epoxy resin, a phenolic resin curing agent, a cure accelerator, an inorganic filler, an amide/imide/ dimer mixed type product obtained by reacting an aminosilane coupling agent represented by formula I with an acid anhydride represented by formula II. By virtue of the properties of the silane coupling agent, the composition has good adhesion to the surfaces of members (e.g. the surfaces of IC chips and the polyimide surfaces of IC chip coats), improved strengths, excellent ordinary temperature storage stability and can give packages having improved reliability.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition for semiconductor encapsulation, which has excellent adhesion to various members, high strength, and good room temperature storage characteristics.

[0002]

2. Description of the Related Art Epoxy resin-based semiconductor encapsulating 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. For example,
High solder resistance is required for surface-mountable devices that have great market needs. Therefore, in order to solve the problem, epoxy resin composition for encapsulation (hereinafter referred to as resin composition) is examined for high filling of inorganic filler, low viscosity epoxy resin, low water absorption curing agent, and high adhesion-imparting agent. And so on. What is important for improving the solder resistance is to improve the adhesion to various members inside the semiconductor package and the strength of the resin composition. Many methods for imparting adhesion to a resin composition have been reported. For example, Tokuhei 3-
In Japanese Patent Publication No. 119049, a vinyl group-containing silane coupling agent is said to be effective in improving adhesion, and is disclosed in JP-B-4-34.
JP-A No. 03-2003 discloses that methoxy-type mercaptosilane and epoxysilane are effective in improving the adhesiveness. However, in any of the methods, although adhesion is improved in some members, it is not possible to adhere well to all members, especially the IC chip surface or the IC chip coat (polyimide) surface, and the resin composition The strength of the product was not sufficiently improved. Therefore, it has been desired to develop a silane coupling agent capable of improving reliability, particularly solder resistance. Further, depending on the coupling agent, since the reactivity with the epoxy resin is too high, the room temperature storage characteristics of the resin composition before molding are deteriorated, which is a practical problem.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a resin composition suitable for surface mounting and a resin composition other than that having good adhesion to various members (particularly the IC chip surface or the polyimide surface of the IC chip coat). However, it was made as a result of studying a silane coupling agent which can further improve the strength of the resin composition and has excellent room temperature storage characteristics. The present invention provides a high-performance resin composition having good solder resistance and excellent moldability.

[0004]

Means for Solving the Problems The inventors of the present invention have made extensive studies as to a silane coupling agent in order to achieve the above object, and as a result, found that a resin composition having the following composition has excellent solder resistance and moldability. I found it. That is, the present invention provides a reaction product comprising an epoxy resin, a phenol resin curing agent, a curing accelerator, an inorganic filler, an aminosilane coupling agent represented by the following formula (1) and an acid anhydride represented by the following formula (2). It is an epoxy resin composition for semiconductor encapsulation as an essential component.

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[0005]

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Hereinafter, the present invention will be described in detail. The epoxy resin used in the present invention is a compound having an epoxy group in the molecule, and examples thereof include orthocresol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, triphenolmethane type epoxy resin, and naphthalene type. Examples thereof include epoxy resin and biphenyl type epoxy resin. The degree of polymerization of these resins and the epoxy equivalent are not particularly limited. However, in the case of a surface mountable resin composition, it is required to increase the blending amount of the inorganic filler, and therefore an epoxy resin having a viscosity when melted as low as possible is desirable. In order to improve the moisture resistance reliability, it is desirable that chlorine ions, sodium ions and other free ions contained in these epoxy resins be as small as possible.

The phenol resin curing agent used in the present invention is a compound having a phenolic hydroxyl group in the molecule, and examples thereof include phenol novolac resin, paraxylylene-modified phenol resin, triphenol methane type phenol resin and bisphenol A. To be There is no problem if these curing agents are modified with silicone. Further, the degree of polymerization, hydroxyl group equivalent, etc. are not particularly limited. Similar to the epoxy resin, a curing agent having a relatively low viscosity is desirable for the surface mounting resin composition. Further, in order to improve the reliability of moisture resistance, it is desirable that chlorine ions, sodium ions and other free ions contained in these phenolic resins are as small as possible.

The curing accelerator used in the present invention may be any one that promotes a chemical reaction between an epoxy group and a phenolic hydroxyl group. For example, 1,8-diazabicyclo (5,
4,0) undecene-7, 2-methylimidazole, triphenylphosphine, tetraphenylphosphine / tetraphenylborate, and the like. When a low-viscosity epoxy resin and a curing agent are blended, the hardness after molding will be low unless the reactivity of the curing accelerator is high, and mold release failure will occur, so that the curing reaction can proceed sufficiently under molding conditions. It is more desirable to properly select the type and amount of such a curing accelerator.

As the inorganic filler used in the present invention,
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 preferable from the viewpoint of improving the fluidity of the resin composition. Regarding the shape of the spherical silica powder, in order to improve the fluidity, it is desirable that the shape of the particles themselves be infinitely spherical and that the particle size distribution be broad.
Further, this inorganic filler is a silane coupling agent of the present invention,
The surface may be previously treated with another silane-based, titanium-based, or other surface-treating agent. The compounding amount of the inorganic filler, the average particle size, and the maximum particle size are not particularly limited.

The silane coupling agent used in the present invention includes the aminosilane coupling agent of the formula (1) and the formula (2).
Is a reaction product with an acid anhydride of. The silane coupling agent, which is the reaction product, is an important technical point in the present invention and will be described in detail. The silane coupling agent used in the present invention is obtained through the reactions shown below.

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The reaction product is an amide of the formula (3-1),
The imide type of formula (3-2), formula (3-3) and formula (3-
The dimer type of 4) is used as a basic structure and is obtained as a single structure or as a mixture of these types depending on the reaction conditions. Further, some of those having a higher molecular weight than the dimer type can be obtained. These three types of structures of amide type, imide type, and dimer type are useful for improving the adhesion and strength with various members.

[Chemical 6]

The silane coupling agent used in the present invention is
The reason why it is effective in improving adhesion and strength will be described below. This silane coupling agent first contains an amide bond. The amide bond is hydrophilic and the hydrophilic functional group improves the adhesion to the metal surface. This is because the metal surface has hydrophilicity due to the presence of free electrons of the metal. Therefore, it is known that a resin composition containing a hydrophilic silane coupling agent adheres well to metals, particularly 42 alloys and copper alloys used in lead frames, aluminum wiring existing on the IC chip surface, and metallic silicon. Has been. Further, the amide bond is easily decomposed to generate an amino group, and this amino group reacts strongly with the epoxy group, so that the adhesive strength between the inorganic filler and the epoxy resin is improved. Further, since the amino group and the epoxy group are very likely to react with each other, the reaction proceeds even at room temperature, and the room temperature storage property of the resin composition before molding is deteriorated. However, when the amide group caps the amino group as in the silane coupling agent of the present invention, the reaction rate between the amino group and the epoxy group at room temperature becomes low, and the room temperature storage property is also greatly improved. At the temperature during molding, the amide bond is broken and an amino group is generated, and reactivity with the epoxy group is first expressed. The reaction between the amino group and the epoxy group has a high temperature dependency, and the silane coupling agent of the present invention can be said to be a reactive coupling agent having potential properties. The silane coupling agent used in the present invention has extremely preferable properties for use as a resin composition, imparts good adhesion and high strength to the resin composition, and as a result, improves solder resistance, Preferable characteristics such as improved reliability can be obtained.

The method for synthesizing the silane coupling agent used in the present invention is not particularly limited as long as the reaction between the silane coupling agent having an amino group and various acid anhydrides can be favorably carried out. The solvent, reaction temperature, reaction time and catalyst used in the reaction are not particularly limited. An example of the synthesis method is shown below. Aminopropyltrimethoxysilane: 43.27 g Anhydrous maleic acid: 28.50 g Acetone 100 g After mixing the above three components in a reaction vessel, the mixture is reacted at 80 to 100 ° C. for 2 hours while stirring. After completion of the reaction, acetone is removed by an evaporator to obtain a reaction product.
Although acetone was removed in this reaction, it may not be necessary depending on the method of use.

The silane coupling agent in the present invention is
It may be simply dispersed in each raw material, a method of reacting / fixing on the surface of the inorganic filler in advance, or a combination of both. It is more preferable to react / immobilize on the surface of the inorganic filler in advance, because the problem of mold fouling due to bleed-out of the silane coupling agent is less likely to occur. The silane coupling agent of the present invention is preferably 0.02 to 1.0 part by weight with respect to 100 parts by weight of the total resin composition. If it is less than 0.02 part by weight, the amount of addition is too small and the characteristics of the silane coupling agent are not exhibited. On the other hand, if the amount exceeds 1.0 part by weight, excessive silane coupling agent bleeds out at various interfaces during molding, and the adhesiveness decreases, which is not preferable.
The silane coupling agent used in the present invention may be used in combination with other silane coupling agents and other coupling agents.

In addition to the components described above, 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, other silane coupling agents, silicone oil, A low stress component such as rubber can be added. The epoxy resin composition of the present invention is an epoxy resin, a curing agent, a curing accelerator, an inorganic filler,
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 ground to obtain a molding material.

The present invention will be specifically described below with reference to examples. << Example 1 >> The following composition Biphenyl type epoxy resin: Formula (E-1) 8.3 parts by weight Phenol aralkyl resin: Formula (H-1) 8.1 parts by weight Spherical silica powder (15 μm) 80 parts by weight Silane cup Ring agent A: Formula (S-1) 0.5 part by weight 1,8-diazabicyclo (5,4,0) undecene-7 (DBU) 0.2 part by weight Carbon black 0.3 part by weight Carnauba wax 0.3 Parts by weight Brominated phenol novolac type epoxy resin 1.0 parts by weight Antimony trioxide 1.3 parts by weight is mixed at room temperature with a mixer, kneaded with a twin-screw roll at 100 ° C., cooled and pulverized to obtain a molding material. . The obtained molding material was evaluated for solder resistance and room temperature storage characteristics.

<Evaluation method> -Soldering resistance: using a tablet of the prepared resin composition,
80 pQFP (1.5 mm thick) is cured at 175 ° C. for 2 minutes and molded. After the molded product was post-cured at 175 ° C. for 8 hours, a semiconductor package was obtained. The obtained package is treated under conditions of 85 ° C. and relative humidity of 85% for 168 hours, and then treated at 240 ° C. in an IR reflow furnace. External cracks are visually observed, and the state of peeling inside the package (the number of chip surface peelings, the number of lead frame peelings, and the number of silver plating portions peeled) is confirmed with an ultrasonic flaw detector. For each resin composition, the number of defectives (external cracks and peeling of each part) out of the 5 packages was counted and evaluated. Room temperature storage characteristics: 2 using the prepared resin composition powder
Leave at 5 ° C for 1 week. Spiral flow after leaving (E
Using a mold according to MMI-I-66, the flow at the time of molding at 175 ° C., pressure 70 Kg / cm ² , and 2 minutes) is measured. The measured value before standing was set as 100%, and the measured value after standing for 1 week was shown by an index.

<< Examples 2 to 14 >> 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. << Comparative Examples 1 to 4 >> Compounded according to the formulation in Table 3 and Example 1
A molding material was obtained in the same manner as above and evaluated in the same manner.

Except for Example 1, the type and blending amount of the epoxy resin, the phenol resin curing agent and the silane coupling agent were changed, and the addition amount of the spherical silica was changed. Further, other additives such as DBU, carbon black, carnauba wax, brominated phenol novolac type epoxy resin and antimony trioxide were always added, and the addition amounts were the same as in Example 1. The epoxy resin, phenol resin curing agent and silane coupling agent used are as follows. -Biphenyl type epoxy resin: Formula (E-1) -Orthocresol novolac type epoxy resin: Formula (E
-2) -Triphenolmethane type epoxy resin: Formula (E-3) -Phenol aralkyl resin: Formula (H-1) -Phenol novolac resin: Formula (H-2) -Triphenolmethane resin: Formula (H-3) ) -Spherical silica powder (average particle size 15 μm) -Processed silica: Spherical silica powder (average particle size 15 μm) 8
0 part by weight and 0.5 part by weight of the silane coupling agent A are mixed in a mixer, and then placed on an aluminum vat for 125
Heat-treated at ℃ for 4 hours

Silane coupling agent A: (formula (S-
Reaction product obtained by reacting the raw material of 1) at a molar ratio (acid anhydride / aminosilane coupling agent) = 1/1. Silane coupling agent B: (the raw material of formula (S-2) is at a molar ratio (acid anhydride Substance / aminosilane coupling agent) = 1 /
Reaction product of 1) Silane coupling agent C: (Raw material of formula (S-3) in molar ratio (acid anhydride / aminosilane coupling agent) = 1 /
Reaction product reacted in 1) Silane coupling agent D: (molar ratio of raw materials of formula (S-4) (acid anhydride / aminosilane coupling agent) = 1 /
Reaction product reacted with 1) Silane coupling agent E: (Raw material of formula (S-5) in molar ratio (acid anhydride / aminosilane coupling agent) = 2 /
Reaction product reacted in 1): Silane coupling agent F: (raw material of formula (S-6) in molar ratio (acid anhydride / aminosilane coupling agent) = 2 /
Reaction product reacted with 1) Silane coupling agent G: (Raw material of formula (S-7) in molar ratio (acid anhydride / aminosilane coupling agent) = 1.
Reaction product reacted at 5/1) Silane coupling agent E: (Raw material of formula (S-8) in molar ratio (acid anhydride / aminosilane coupling agent) = 0.
7/1 reaction product) Silane coupling agent F: Formula (S-9)

Raw materials for the epoxy resin, phenol resin and silane coupling agent used in Examples and Comparative Examples are shown below.

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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]

According to the present invention, it is possible to obtain a high-performance epoxy resin composition for semiconductor encapsulation, which has high adhesion to various members, excellent solder resistance, and high performance. Therefore, a dry pack-less surface-mountable resin composition is obtained, and the reliability of the package is improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 23/31

Claims (1)

[Claims] An epoxy resin, a phenol resin curing agent,
An epoxy for semiconductor encapsulation, which comprises a reaction product consisting of a curing accelerator, an inorganic filler, an aminosilane coupling agent represented by the following formula (1) and an acid anhydride represented by the following formula (2) as essential components. Resin composition. Embedded image Embedded image