JP2000273285A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for semiconductor sealing use excellent in releasability, flowability, soldering resistance, and reliability. SOLUTION: This composition essentially comprises an epoxy resin, a phenolic resin curing agent, a curing promoter, an inorganic filler, an amino group- bearing silane coupling agent, and oxidized paraffin 5-80 in acid value.

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 moldability, soldering resistance after moisture absorption, and the like, and a semiconductor device using the same.

[0002]

2. Description of the Related Art In recent years, in the market trend of miniaturization, weight reduction and high performance of electronic equipment, semiconductor integration is progressing year by year, and surface mounting of semiconductor devices is promoted. Demands on materials are becoming more and more severe. In particular, in the current situation where surface mounting of semiconductor devices is becoming common, a semiconductor device that has absorbed moisture is exposed to high temperatures during soldering, and cracks occur in the package due to the explosive stress of vaporized water vapor, or semiconductor devices may be damaged. And the occurrence of peeling at the interface between the lead frame and the semiconductor encapsulating material causes defects that greatly impair electrical reliability. Prevention of these defects, that is, improvement of solder resistance, has become a major issue. To improve the solder resistance,
The semiconductor encapsulating material has been trying to reduce the moisture absorption, lower the thermal expansion, and increase the strength of the semiconductor device by blending a large amount of an inorganic filler. For this reason, low-viscosity epoxy resins and crystalline epoxy resins that are crystalline at room temperature but exhibit extremely low viscosity above the melting point are used. A method for preventing a decrease in fluidity during molding of a resin composition is generally adopted.

However, low-viscosity epoxy resins and crystalline epoxy resins are generally low-molecular-weight compounds, and therefore have a low cross-linking density in a cross-linked structure obtained by heating to three-dimensionality during molding. Therefore, since the molded product has low mechanical strength and elastic modulus after molding, the molded product adheres to the mold at the time of release from the mold, or the molded product has cracking or chipping. It has the disadvantage of being inferior. To improve the releasability, mixing a large amount of a release agent is mentioned as a countermeasure. On the other hand, a large amount of the release agent is present inside the semiconductor device at the time of molding, and a semiconductor element and a lead frame on which the semiconductor element is mounted. To the interface between the resin and the cured product of the resin composition, resulting in a significant loss of adhesion at these interfaces. As a result, when the semiconductor device is subjected to the soldering process after the moisture absorption, the interface may be peeled off, or the package may be cracked due to the peeling. For this reason, development of a resin composition having excellent releasability and solder resistance during molding has been desired.

[0004]

SUMMARY OF THE INVENTION The present invention provides a semiconductor epoxy resin composition which is excellent in mold releasability at the time of molding and is excellent in solder resistance of a semiconductor device, and a semiconductor device using the same. is there.

[0005]

The present invention provides (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator,
(D) an inorganic filler, (E) a silane coupling agent, particularly preferably a silane coupling agent having an amino group
And (F) an epoxy resin composition for semiconductor encapsulation containing paraffin oxide having an acid value of 5 to 80 as an essential component.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention refers to all monomers, oligomers and polymers having two or more epoxy groups in one molecule, such as bisphenol A type epoxy resin and phenol novolak type epoxy resin. , Ortho-cresol novolak type epoxy resin, naphthol novolak type epoxy resin, triphenol methane type epoxy resin, dicyclopentadiene modified phenol type epoxy resin, phenol aralkyl type epoxy resin, terpene modified phenol type epoxy resin,
Examples include, but are not limited to, biphenyl-type epoxy resins, hydroquinone-type epoxy resins, stilbene-type epoxy resins, and bisphenol-F-type epoxy resins. These epoxy resins may be used alone or as a mixture. In order to improve the solder resistance of the semiconductor device, the amount of the inorganic filler in the resin composition is increased to reduce the moisture absorption, lower the thermal expansion, and increase the strength of the cured product of the obtained resin composition. In order to achieve this, it is particularly preferable to use, as the epoxy resin, a crystalline epoxy resin which exhibits crystallinity at normal temperature and becomes a liquid having an extremely low viscosity when the melting point is exceeded.

The phenolic resin used in the present invention refers to all monomers, oligomers and polymers having two or more phenolic hydroxyl groups in one molecule.
Phenol novolak resin, cresol novolak resin, phenol aralkyl resin, terpene-modified phenol resin, dicyclopentadiene-modified phenol resin, naphthol novolak resin, triphenolmethane-type resin, bisphenol compound, and the like, but are not limited thereto. . Further, these phenol resins may be used alone or in combination.

The curing accelerator used in the present invention includes:
A substance that can serve as a catalyst for a crosslinking reaction between the epoxy resin and the phenol resin. Specific examples include amine compounds such as tributylamine and 1,8-diazabicyclo (5,4,0) undecene-7, and triphenylphosphine. ,
Examples include organic phosphorus compounds such as tetraphenylphosphonium / tetraphenylborate salts, and imidazole compounds such as 2-methylimidazole, but are not limited thereto. These curing accelerators may be used alone or as a mixture.

The inorganic filler used in the present invention includes, for example, fused silica, crystalline silica, alumina, silicon nitride, aluminum nitride and the like. When the amount of the inorganic filler is particularly large, it is common to use fused silica. Fused silica can be used in either crushed or spherical form. However, in order to increase the blending amount of the fused silica and suppress an increase in the melt viscosity of the molding material, it is preferable to mainly use a spherical form. In order to further increase the blending amount of the spherical silica, it is desirable to adjust the particle size distribution of the spherical silica to be wider.

The silane coupling agents used in the present invention include γ-glycidoxypropyltrimethoxysilane, β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane In addition to compounds such as silane and γ- (methacryloxypropyl) trimethoxysilane,
γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N
-A silane coupling agent having an amino group, such as phenyl-γ-aminopropyltrimethoxysilane, has excellent mechanical strength of the cured product, and also has an improved interfacial adhesive force between the semiconductor device or lead frame and the cured product of the epoxy resin composition. It has the following characteristics. For this reason, it is particularly preferable because it has excellent soldering resistance in a soldering process after moisture absorption and a temperature cycle test.

The oxidized paraffin wax having an acid value of 5 to 80 used in the present invention is a general term for an oxide obtained by, for example, oxidation of paraffin wax by air or addition of an acid. be introduced. The paraffin wax as the raw material is obtained by separating and purifying a distillate oil or a residual oil obtained by distilling a petroleum wax which is a natural wax under reduced pressure, and usually has 20 to 60 carbon atoms.
The molecular weight is about 300-900. In general, examples of the release agent used in the epoxy resin composition for semiconductor encapsulation include carnauba wax, montanic acid esters, stearic acid and metal salts thereof, and polyolefin oxide such as polyethylene and polyethylene oxide. However, an epoxy resin composition using a low-viscosity epoxy resin, a crystalline epoxy resin, or the like has insufficient mold releasability during molding even when a conventional mold release agent is used. In particular, when a silane coupling agent having an amino group is used, the releasability is further deteriorated due to the good adhesion of the silane coupling agent.
On the other hand, when an oxidized paraffin having an acid value of 5 to 80 is used, the releasability from a mold can be improved with a small amount of addition. In particular, even when a silane coupling agent having an amino group is used, there is a characteristic that the releasability is good. Furthermore, unlike oxidized polyolefin compounds such as oxidized polyethylene having a similar structure, the addition of paraffin oxide significantly reduces the melt viscosity at the molding temperature of the epoxy resin composition by addition, thereby providing excellent fluidity during molding. There is. The acid value of oxidized paraffin can be determined by neutralization titration with a potassium hydroxide solution by a conventional method. The unit is expressed in mgKOH / g.

The acid value of the oxidized paraffin wax used in the present invention is in the range of 5-80. If the acid value is less than 5, the compatibility with the resin is low, and bleeding easily occurs on the surface of the molded product or the mold during molding, so that the surface of the molded product or the surface of the mold is contaminated when molded continuously. Furthermore, the adhesiveness at the interface between the semiconductor element or the lead frame and the cured product of the epoxy resin composition is also reduced, and as a result, the solder resistance is poor. on the other hand,
If the acid value exceeds 80, the compatibility with the resin becomes too good, the reaction with the epoxy resin is likely to occur, the viscosity at the time of molding increases, and the fluidity decreases. The gold wire connected to the element is easily deformed. In particular, when aminosilane is used as the silane coupling agent, the acid value is preferably 80 or less because the reaction between the paraffin oxide and the amino group is more likely to occur. As long as the properties of the oxidized paraffin of the present invention having an acid value of 5 to 80 are not impaired, it can be used in combination with the above-mentioned other release agent.

The epoxy resin composition of the present invention comprises (A)
The component (F) is an essential component, but if necessary, a brominated epoxy resin, a flame retardant such as antimony trioxide, a coloring agent such as carbon black, a low stress additive such as silicone oil, silicone rubber, and synthetic rubber. May be appropriately compounded. The epoxy resin composition of the present invention is obtained by mixing the components (A) to (F), other additives, and the like, kneading with heat using a heating kneader or a hot roll, and then cooling and pulverizing. This resin composition is generally used in powder form or as a tablet. In order to manufacture a semiconductor device by encapsulating an element such as a semiconductor using the epoxy resin composition of the present invention, it is sufficient to cure and mold by a conventional molding method such as transfer molding, compression molding, injection molding and the like.

[0014]

EXAMPLES Example 1 Epoxy resin containing 3,3 ′, 5,5′-tetramethylbiphenol diglycidyl ether as a main component (YX4000H, manufactured by Yuka Shell Epoxy Co., Ltd., melting point 105 ° C., epoxy equivalent) 195; hereinafter referred to as biphenyl epoxy resin) 7.9 parts by weight Phenol aralkyl resin (manufactured by Mitsui Chemicals, Inc., XL225-LL, softening point 75 ° C., hydroxyl equivalent 175; hereinafter referred to as phenol aralkyl resin) 7.1 parts by weight Spherical melting Silica 84.0 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 0.2 part by weight γ-aminopropyltrimethoxysilane 0.3 part by weight Paraffin oxide A (acid value) 15, softening temperature 85 ° C) 0.2 parts by weight of carbon black 0.3 parts by weight were mixed using a mixer, and then mixed. 90 ℃ and 2
The mixture was kneaded 20 times using a biaxial roll at 5 ° C., and the obtained kneaded material sheet was cooled and pulverized to obtain an epoxy resin composition. The properties of the obtained epoxy resin composition were evaluated by the following methods. Table 1 shows the results.

Evaluation method Spiral flow: Using a mold for spiral flow measurement in accordance with EMMI-I-66, a mold temperature of 175 ° C.
The measurement was performed at an injection pressure of 70 kg / cm ² and a curing time of 2 minutes. Heat strength: Flexural strength at 240 ° C. is determined according to JIS-K6911.
It measured according to. The unit is kgf / mm ² . Gold wire deformation: 144pQFP package (package size 20 × 20 × 1.4mm, chip size 9 × 9m
m, gold wire: 25 μm diameter, lead frame: copper) were molded at a mold temperature of 175 ° C. and a molding pressure of 75 kgf / cm ² for 2 minutes. The obtained package was observed with a soft X-ray fluoroscope, and the deformation rate of the gold wire was represented by (flow amount) / (gold wire length) (unit%). Solder resistance: The 144pQFP package whose gold wire deformation was measured was post-cured at 175 ° C. for 8 hours. The obtained semiconductor package is placed in an environment of 85 ° C. and 85% relative humidity for 7 minutes.
It was left for 2 hours and 168 hours, and then immersed in a 240 ° C. solder bath for 10 seconds. Observe external cracks with a microscope,
The number of cracks ((the number of packages in which cracks occurred) / (the number of all packages) × 100) was expressed in%. Releasability: A package of 144 pQFP whose gold wire deformation was measured was molded 10 times in a row. In these 10 moldings, the number of times of adhesion to the mold at the time of release from the mold and the occurrence of cracks / chips in the molded product was 5 or more times, Δ was 1 to 4 times, and 発 生 was not generated.

Examples 2 to 5, Comparative Examples 1 to 5 An epoxy resin composition was obtained in the same manner as in Example 1 except that the composition of Example 1 was used as a basic compound and the types of the release agent and the silane coupling agent were changed. Evaluation was performed in the same manner as in Example 1. The properties of the oxidized paraffin and polyethylene oxide used in Examples and Comparative Examples are as follows. Acid value (mg KOH / g) Softening point (° C.) Oxidized paraffin B 72 88 Oxidized paraffin C 8 102 Oxidized paraffin D 94 97 Oxidized paraffin E 4 86 Oxidized polyethylene 17 105 Formulations and results are shown in Tables 1 and 2.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

The epoxy resin composition of the present invention has a releasability,
Because of its excellent fluidity, continuous moldability and gold wire deformation do not occur, so that the moldability is excellent, and the semiconductor device sealed with this is excellent in solder resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01L 23/29 H01L 23/30 R 23/31 F term (Reference) 4J002 AE033 CC03X CC04X CC05X CC06X CD01W CD02W CD03W CD05W CD06W CD07W CE00X DE147 DF017 DJ007 DJ017 EN026 EU096 EU106 EW016 EX038 EX068 EX078 EX088 EY016 FD017 FD156 FD160 GQ05 4J036 AA01 AB01 AB07 AC01 AC02 AD01 AD07 AD08 AE05 AF06 AF08 AF19 AJ02 AJ05 FA07 DD07 FA04 AA01 BA01 CA21 EA02 EB03 EB04 EB06 EB07 EB08 EB09 EB12 EB19 EC01 EC03

Claims (3)

[Claims] (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, (E)
An epoxy resin composition for semiconductor encapsulation comprising a silane coupling agent and (F) paraffin oxide having an acid value of 5 to 80 as essential components. 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the silane coupling agent is a silane coupling agent having an amino group. 3. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1 or 2.