JPH06151479A - Conductive resin paste and semiconductor device - Google Patents

Abstract

PURPOSE:To provide conductive resin paste which does not generate any void when it hardens, can be hardened within one minute on a hot plate, has an excellent adhesive strength against the surfaces of various kinds of substrates, and can be reduced in thermal stress after hardening. CONSTITUTION:The title paste is composed of an epoxy resin having two or mote epoxy groups in one molecule, phenolated polybutadiene having two or more phenolic hydroxyl groups in one molecule, and conductive filler. This invention also relates to a semiconductor device using the paste.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive resin paste used for adhering semiconductor integrated circuit elements such as ICs and LSIs to base materials such as lead frames and printed circuit boards, and a semiconductor device using the same.

[0002]

2. Description of the Related Art A semiconductor integrated circuit device is provided with a lead frame,
As a method for adhering to a substrate such as a printed circuit board, Au-S
A method using an i-eutectic alloy, solder, a conductive resin paste, or the like is known. The bonding method using the Au-Si eutectic alloy is performed by forming a gold (Au) plating film on a base material in advance, mounting a gold foil ribbon, and further mounting a semiconductor integrated circuit element on the substrate.
It is melt-pressed at a high temperature of 00 ° C. This Au-Si eutectic alloy method is excellent in electric conductivity, but is expensive because gold is used, and in order to bond a semiconductor integrated circuit element which becomes large in size with the high integration of the semiconductor integrated circuit, The thermal stress after the high temperature pressure bonding is high, which causes cracks in the semiconductor integrated circuit element, which is not preferable. In the method using solder, a gold plating film is previously formed on the back surface of the semiconductor integrated circuit element and the front surface of the base material, and the melting point of the solder (26
(0 to 300 ° C.) or higher and melt-pressed. This soldering method also has excellent electrical conductivity, but is expensive because gold plating on the back surface of the semiconductor integrated circuit element is essential.

In the method using a conductive resin paste, a paste prepared by adding a conductive filler and a diluent to an epoxy resin, a polyimide resin or the like as a base is applied on a substrate, and a semiconductor integrated circuit element is pressure-bonded. It is cured by heating. Although this conductive resin paste method is inferior in electric conductivity to the Au-Si eutectic alloy method and the solder method, it is the cheapest and has a low curing temperature of 150 to 200 ° C and a low thermal stress. Most widely used. on the other hand,
The required characteristics for conductive resin paste are becoming more sophisticated as the market for semiconductor integrated circuits expands and the integration becomes higher. In particular, voids do not occur in the conductive resin paste, and curing within 1 minute on the hot platen is possible. It is required that it is possible, has sufficient adhesive strength to various substrate surfaces, and can reduce thermal stress after curing. However, conventional conductive resin pastes have not yet met all these requirements.

[0004]

SUMMARY OF THE INVENTION The present invention provides a conductive resin paste capable of satisfying the characteristics required for the above-mentioned conductive resin paste and a semiconductor device using the same.

[0005]

The present invention provides (A) an epoxy resin having two or more epoxy groups in one molecule,
(B) A conductive resin paste containing a phenolized polybutadiene having two or more phenolic hydroxyl groups in one molecule and (C) a conductive filler, and a semiconductor integrated circuit element and a substrate are bonded with this paste. , A semiconductor device formed by sealing.

Epoxy resins having two or more epoxy groups in one molecule include polyphenol compounds such as bisphenol A, bisphenol AD, bisphenol F, bisphenol S, phenol novolac resin, cresol novolac resin and alkylated biphenol. And an epoxy resin derived from epichlorohydrin, a polyfunctional epoxy resin as described below,

[Chemical 1]

[Chemical 2]

[Chemical 3]

[Chemical 4]

[Chemical 5] An epoxy resin having the following dihydroxynaphthalene skeleton,

[Chemical 6]

[Chemical 7] Alicyclic epoxy resin, for example, EHPE-3150 (trade name, manufactured by Daicel Chemical Industries, Ltd.)

[Chemical 8] Etc. can be used. These epoxy resins are used alone or in combination of two or more.

Examples of polybutadiene having two or more phenolic hydroxyl groups in one molecule include Nisseki polybutadiene phenol compound P-type (trade name, manufactured by Nippon Petrochemical Co., Ltd.). In addition, a part of the polybutadiene having a phenolic hydroxyl group is a phenol novolac resin (for example, manufactured by Meiwa Kasei Co., Ltd., trade name H-
It can be used instead of 1).

As the conductive filler, metal powder such as gold, silver, copper, nickel and stainless can be used. Among these, silver is the most excellent in terms of conductivity, purity and handleability. The shape of the conductive filler may be spherical, scaly, dendritic, or amorphous, and the conductive fillers of these various shapes may be used alone or in combination of two or more. In addition, an insulating filler may be mixed and used within a range where the conductivity is not lost.

The compounding ratio of the epoxy resin and the phenolized polybutadiene is preferably in the range of 0.01 to 20.0 equivalents of the phenolic hydroxyl group of the phenolized polybutadiene with respect to 1 equivalent of the epoxy group of the epoxy resin. Further, the compounding amount of the conductive filler is preferably in the range of 50 to 2000 parts by weight with respect to 100 parts by weight of the total of the epoxy resin and the phenolized polybutadiene.

The conductive resin paste of the present invention may further contain a curing accelerator, a diluent and various additives. Examples of the curing accelerator include imidazole derivatives (for example, Shikoku Chemicals Co., Ltd., trade name Cureazole), tetraphenyl borate salts (for example, Kitako Chemical Co., Ltd.,
Trade name TPP-K, EMZ-K, San-Apro Co., Ltd., trade name U-CAT5002), dicyandiamide,
A dibasic acid dihydrazide compound (for example, products manufactured by Japan Hydrazine Industry Co., Ltd., products ADH, SDH, IPDH) can be used. These may be used alone or in combination of two or more.

The diluent is added to dissolve the epoxy resin and the phenolized polybutadiene so as to facilitate the formation of a paste. Such diluents include ethyl cellosolve, butyl cellosolve, carbitol, butyl carbitol, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate,
Organic solvents having a boiling point of 100 ° C. or higher such as N-methylpyrrolidone and α-terpineol, compounds having one epoxy group such as phenylglycidyl ether and alkylphenylglycidyl ether in one molecule, and γ-glycidoxypropyltrimethoxysilane The epoxy silane compound and the like can be used.

[0012] Various additives are added to improve the adhesive strength, wettability, dispersibility of the conductive filler, and the like. As such additives, various silane-based, titanium-based, aluminum-based coupling agents, various surfactants, fluorine-containing compounds, organometallic compounds and the like can be used.

[0013] Dissolving and dispersing devices such as a stirrer, raker, three rolls, ball mill, planetary mixer, etc. are appropriately combined, and the above-mentioned components are collectively or divided and heated, mixed and dissolved as necessary. A uniform conductive resin paste can be obtained by combining operations such as pulverization, dispersion, and kneading.

The conductive resin paste of the present invention is applied on a substrate such as a lead frame or a printed wiring board by a dispensing method,
Apply using stamping method, transfer method, screen printing method, and other coating methods as appropriate, place semiconductor integrated circuit elements on and press-bond, and use hot air circulating dryer, hot plate curing device, belt curing device as appropriate. Hardened. Further, a semiconductor device is manufactured through a wire bonding process and a sealing process.

[0015]

EXAMPLES The present invention will be described below with reference to examples. Examples 1 to 3 YDF-170 (manufactured by Tohto Kasei Co., Ltd., trade name bisphenol F type epoxy resin, epoxy equivalent = 170), T
ACTIX-742 (manufactured by Dow Chemical Company, trade name polyfunctional epoxy resin, epoxy equivalent = 165), YDCN-7
02 (manufactured by Tohto Kasei Co., Ltd., trade name cresol novolac type epoxy resin, epoxy equivalent = 220), BP-7
00-300 (Nippon Petrochemical Co., Ltd., trade name phenolated polybutadiene, phenolic hydroxyl group equivalent = 33)
0), ED-509 (manufactured by Asahi Denka Co., Ltd., trade name: alkylphenyl glycidyl ether) dicyandiamide (reagent), 2P4MHZ (manufactured by Shikoku Chemicals Co., Ltd., trade name: 2-phenyltimethylimidazole), TC-20.
Using E (manufactured by Tokuriki Kagaku Kenkyusho Co., Ltd., trade name, scaly silver powder), a conductive resin paste was obtained with the composition shown in Table 1. As a result of investigating the characteristics of this conductive resin paste, as shown in Table 1, it is possible to cure by heating at 200 ° C. for 60 seconds using a hot plate type curing device, and sufficient adhesive strength at room temperature. Can be obtained. In addition, the shear adhesive strength at the time of heating at 350 ° C. was 1.0 MPa, which was a sufficient value for all of the lead frames plated with gloss, semi-gloss, and matte silver.

Comparative Examples 1-2 In Examples 1 to 3, H-1 (made by Meiwa Kasei Co., Ltd., trade name: phenol novolac resin, phenolic hydroxyl group equivalent = 107) was used in place of BP-700-300. , A conductive resin paste was prepared. Comparative Examples 1 and 2
Shows a shear adhesive strength at 350 ° C heat of 1.0 MPa or more to the lead frame plated with semi-gloss or matte silver, but to the lead frame plated with gloss silver Showed a low value of 0.5 to 0.7 MPa. Also, in terms of chip warpage, Examples 1 to 3
Comparative Examples 1 and 2 are larger than that of Comparative Example 1, and it is shown that Comparative Example generates higher thermal stress.

[0017]

[Table 1]

[Characteristic Evaluation Method] Adhesive Strength (1): Two 0.4 mm thick silicon wafers were used.
Chips cut out to 2 mm were crimped to a semi-glossy silver-plated copper frame using a conductive resin paste of each formulation, and left on a 200 ° C hot plate for 60 seconds Shear adhesion of test pieces Force was measured at room temperature using a push-pull gauge. Adhesive force (2): The shear adhesive force of the test piece prepared in the same manner as the adhesive force (1) was allowed to stand on a heating plate at 350 ° C. for 20 seconds and measured at that temperature. Adhesive force (3): The same measurement as the adhesive force (2) was performed using a 42 alloy frame plated with glossy silver. Adhesive force (4): The same measurement as the adhesive force (2) was performed using a matte silver-plated copper frame. Void: Apply the conductive resin paste of each formulation to a matte silver-plated copper frame and apply 5 x 5 x
When a 0.6 t (mm) glass chip was pressure-bonded and left on a heating plate at 200 ° C. for 60 seconds, the occurrence of voids was observed with an optical microscope, and one having a silver paste occupancy of 80% or more was regarded as good. . Chip warp: Apply the conductive resin paste of each formulation to a matte silver plated copper frame and apply 5 x 13
X 0.4t (mm) silicon chip is crimped to 200
The size of the warp when left for 60 seconds on a hot plate of ° C was measured by a surface roughness meter. Viscosity: The viscosity at 25 ° C was measured using an E-type viscometer manufactured by Tokyo Keiki Co., Ltd.

[0019]

EFFECTS OF THE INVENTION By using the conductive resin paste of the present invention, voids are not generated in the cured product of the conductive resin paste, and it is possible to cure within 1 minute on the hot platen, and it is glossy, semi-glossy, non-glossy. It has a sufficient adhesive force to the surface of a substrate having various plated surfaces such as, and can reduce the thermal stress after curing, and it is possible to produce a highly reliable semiconductor device.

Claims (3)

[Claims] 1. An epoxy resin having (A) two or more epoxy groups in one molecule, (B) a phenolized polybutadiene having two or more phenolic hydroxyl groups in one molecule, and (C) a conductive filler. Conductive resin paste containing. 2. The conductive resin paste according to claim 1, wherein a part of the phenolized polybutadiene having two or more phenolic hydroxyl groups in one molecule is replaced with a phenol novolac resin. 3. A semiconductor integrated circuit device and a base material.
A semiconductor device obtained by bonding the conductive resin paste as described above and then sealing.