JPH0536738A - Conductive resin paste and semiconductor device - Google Patents

Abstract

PURPOSE:To relax thermal stress by using a reaction product of epoxy resin having at least two epoxy groups in one molecule with a fatty monocarboxylic acid as a conductive resin. CONSTITUTION:The conductive resin paste includes epoxy resin, a hardening agent, a conductive filler and a diluent. A semiconductor device and a substrate are bonded with the conductive resin paste which is a reaction product of the epoxy resin having at least two epoxy groups in one molecule with a fatty monocarboxylic acid. After bonded, the substrate is sealed with the resin, thereby forming a semiconductor device. The monocarboxylic acid includes acetic acid, propionic acid and crotonic acid. As the hardening agent, there are included phenol borax resin and phenol aralkyl resin. In addition, the conductive filler includes gold, silver and copper particles while the diluent includes butyl Cellosolve acetate is cited. It is, therefore, possible to prevent the generation of thermal stress.

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, more specifically, a conductive resin suitable for adhering semiconductor elements such as IC and LSI to substrates such as lead frames, ceramic wiring boards and glass epoxy wiring boards. The present invention relates to a paste and a semiconductor device using the paste.

[0002]

2. Description of the Related Art In recent years, conductive resin paste has been mainly used for bonding (die bonding) between semiconductor elements such as IC and LSI and substrates such as lead frames. However, with the rapid progress of the semiconductor industry, the problem of thermal stress due to the difference in the coefficient of thermal expansion between a large semiconductor element and a substrate such as a lead frame has become apparent. As a means for solving this, conductive resin paste ( 1) A method of adding carboxylic acid terminated polybutadiene (JP-A-62-199669), (2) a method of adding epoxidized polybutadiene (JP-A-63-161015), and (3) having an amino group or a hydroxyl group. A method of adding a dimethylsiloxane compound (Japanese Patent Laid-Open No. 63-10104) has been proposed.

However, in the method (1), the workability of applying the conductive resin paste is poor because the molecular weight of the carboxylic acid-terminated polybutadiene-modified epoxy resin is large, and in the method (2), the curability of the epoxidized polybutadiene is low. Therefore, it is difficult to cure in a short time and the productivity is poor. Furthermore, in the method (3), the compatibility between the dimethylsiloxane compound and the epoxy resin is poor, so that there is a drawback such as separation during storage of the conductive paste. is there.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and provides a conductive resin paste which is excellent in workability, curability and compatibility, and is also excellent in thermal stress relaxation effect. To do.

[0005]

The present invention provides a conductive resin paste containing (A) epoxy resin, (B) curing agent, (C) conductive filler and (D) diluent, wherein the epoxy resin (A ) Is a conductive resin paste which is a reaction product of an epoxy resin having two or more epoxy groups in one molecule and an aliphatic monocarboxylic acid, and after bonding a semiconductor element and a substrate with this conductive resin paste, The present invention relates to a sealed semiconductor device.

The epoxy resin having two or more epoxy groups in one molecule used in the present invention includes (1) for example, Epicoat 828 under the trade name of Yuka Shell Epoxy Co.,
Epicoat 1001, Mitsui Petrochemical Co., Ltd., trade name R-17
10, bisphenol A, bisphenol AD, bisphenol F, and bisphenol S diglycidyl ether such as YDF-170 manufactured by Tohto Kasei Co., Ltd., trade name EBPS-300 manufactured by Nippon Kayaku Co., Ltd., (2) For example, a product manufactured by Dow Chemical Co., Ltd. Polydencidyl ethers of phenol novolac resins and cresol novolac resins such as name DEN-438, Toto Kasei Co., Ltd., trade names YDCN-702, YDCN-704, (3) For example, the following structural formula (I)

[Chemical 1] (N in the formula is 0 or a positive integer) represented by Yuka Shell Epoxy Co., Ltd., trade name 1032H, Nippon Kayaku Co., Ltd. EPPN
-501H, trade name TACTIX-7 manufactured by Dow Chemical Company
42, the following structural formula (II)

[Chemical 2] Mitsui Petrochemical Co., Ltd., trade name VG-3101, represented by the following structural formula (III)

[Chemical 3] Polyhydric phenol polyglycidyl ether such as trade name 1031S manufactured by Yuka Shell Epoxy Co., Ltd. (4) For example, the following structural formula (IV)

[Chemical 4] Product name HP-40 manufactured by Dainippon Ink and Chemicals, Inc.
32, the following structural formula (V)

[Chemical 5] A polyglycidyl ether having a naphthalene skeleton such as trade name EXA-4300 manufactured by Dainippon Ink and Chemicals, Inc. (m in the formula is an integer of 1 or more), (5) For example, U
Alicyclic epoxy resins such as CC trade name ERL-4201, 4221 and Daicel Chemical Industries trade name EHPE-3150.

Examples of the aliphatic monocarboxylic acid used in the present invention include acetic acid, propionic acid, crotonic acid,
Butyric acid, tiglic acid, pivalic acid, valeric acid, sorbic acid,
Caproic acid, 2-ethylbutyric acid, tert-butylacetic acid,
Isocaproic acid, heptanoic acid, heptenoic acid, 2-octenoic acid, caprylic acid, 2-ethylhexanoic acid, 2-propylpentanoic acid, 2-nonenoic acid, nonanoic acid, 2-decenoic acid, capric acid, undecylenic acid, undecylic acid , Lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, 2-hexyldecanoic acid, stearic acid, isostearic acid, oleic acid, elaidic acid, heptadecanoic acid, heptadecenoic acid, linoleic acid, linolenic acid, parinaric acid, nonadecanoic acid , Arachidic acid and the like. Among these, those having a double chain bond having 6 to 18 carbon atoms are preferable from the viewpoints of the effect of reducing thermal stress, the compatibility with solvents and other resins, and the reduction in viscosity of the conductive paste.

In the present invention, as the epoxy resin (A), a reaction product of an epoxy resin having two or more, preferably three or more epoxy groups in one molecule and an aliphatic monocarboxylic acid is used. When an aliphatic monocarboxylic acid is reacted with an epoxy resin having two epoxy groups in one molecule, a reaction product having one epoxy group in one molecule may be produced. If a large amount of the reaction product is contained in the conductive resin paste, the curing reactivity may decrease, so it is preferable to use an epoxy resin having 3 or more epoxy groups in one molecule.

The reaction between the epoxy resin having two or more epoxy groups in one molecule and the aliphatic monocarboxylic acid is carried out in the presence of a solvent, if necessary, or by adding a catalyst, if necessary, to 100 to 190. It can be performed by stirring at a temperature of ° C for a certain period of time. The reaction can be traced by titrating the unreacted aliphatic monocarboxylic acid with an alcohol solution of potassium hydroxide. As the catalyst added as necessary, tertiary amines, imidazoles, triphenylphosphine, etc. are used, and the solvent is preferably a solvent which can be used as it is when it is used as a conductive paste.

The mixing ratio of the epoxy resin having two or more epoxy groups in one molecule and the aliphatic monocarboxylic acid is
From the viewpoint of curability and compatibility, the aliphatic monocarboxylic acid is added in an amount of 0.01 to 0.
It is preferably 40 carboxylic acid equivalents. In the present invention, from the viewpoint of improving the curability of the conductive resin paste, an epoxy resin having two or more epoxy groups in one molecule is used as the epoxy resin (A) in addition to the above reaction product. Preferably.

As the curing agent (B) used in the present invention,
Phenol novolac resins such as product name H-1 manufactured by Meiwa Kasei Co., phenol aralkyl resins such as XL-225 product name manufactured by Mitsui Toatsu Chemicals, Inc. product name SP-1 manufactured by Nippon Carbide Co.
Dicyandiamide such as 0, dibasic acid dihydrazide such as product name ADH, IDH, SDH manufactured by Japan Hydrazine Industry Co., Ltd.,
Shikoku Kasei product name Curezol 2MZ, 2E4MZ,
2E4MZ-CN, 2E4MZ-AZINE, C ₁₁ Z,
C ₁₁ Z-CN, C ₁₁ Z-CNS, C ₁₇ Z, 2PZ, 2P
4MZ, 2PZ-CN, 2PZ-CNS, 2PZ-O
I, imidazoles such as K, 2MA-OK, 2PHZ, 2P4MHZ, trade names TPPK, EMZ-K manufactured by Hokuko Kagaku KK
Organic boron salt such as U-Cat 5002 manufactured by San-Apro Co., Ltd., DBU, U-Cat 1 manufactured by San-Apro Co., Ltd.
02, 106, 830, 340, tertiary amines such as benzyldimethylamine, tri-2,4,6-dimethylaminomethylphenol, and salts thereof. These may be used alone or in combination of two or more. The amount of the curing agent used is sufficient to keep the pot life of the conductive resin paste above a certain level and to maintain practical curability, but the total amount of the epoxy resin (A) is usually 100. It is in the range of 0.1 to 200 parts by weight with respect to parts by weight.

Examples of the conductive filler (C) used in the present invention include fine powders of conductive metals such as gold, silver, copper, nickel, aluminum, iron and stainless, among which the purity is high. A silver powder having good stability is preferable.
These may be appropriately mixed and used, and it is also possible to mix an inorganic insulator within a range in which conductivity is not lost. There is no particular limitation on the shape of the conductive filler, a flake shape,
Dendritic and spherical fillers can be used alone or in combination. Examples of commercially available products include Silvest TCG-1 (silver powder) manufactured by Tokuriki Kagaku Kenkyusho. The amount of the conductive filler (C) used is usually 100 to 100 relative to 100 parts by weight of the total amount of the epoxy resin (A) and the curing agent (B).
0 parts by weight.

The diluent (D) used in the present invention is not particularly limited, but it is excellent in compatibility with epoxy resin, aliphatic monocarboxylic acid, curing agent and the like, and to some extent from the viewpoint of workability of the resin paste. Those having a boiling point that is difficult to volatilize are preferable. Examples of such diluents include butyl cellosolve, butyl cellosolve acetate, carbitol,
Carbitol acetate, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, butyl carbitol, butyl carbitol acetate, α-
Organic solvents such as terpineol and diacetone alcohol, reactive monoglycidyl ethers such as phenylglycidyl ether, p-tert-butylphenylglycidyl ether and p-sec-butylphenylglycidyl ether, KBM-403, LS-7970
(Shin-Etsu Chemical Co., Ltd. product name), TSL-8350, TSL-
8355, TSL-9905 (trade name of Toshiba Silicone Co., Ltd.), PGE (trade name of Nippon Kayaku Co., Ltd.), PP101 (trade name of Toto Kasei Co., Ltd.), YED-122 (trade name of Yuka Shell Epoxy Co., Ltd.), ED -502, ED-503 (trade name of Asahi Denka Co., Ltd.) and the like, and reactive diluents having 1 to 2 epoxy groups in one molecule. These may be used alone or in combination of two or more. The amount of the diluent (D) used is usually 0 to 800 parts by weight based on 100 parts by weight of the total amount of the epoxy resin (A) and the curing agent (B).

The conductive resin paste of the present invention contains a silane coupling agent, a titanium coupling agent, and other adhesiveness improving agents, a nonionic surfactant, a fluorinated surfactant, a wetting improving agent such as silicone oil, and an erase agent. A foaming agent or the like can be added as appropriate. The conductive resin paste of the present invention, for example,
Epoxy resin (A), which is a reaction product of an epoxy resin having two or more epoxy groups in one molecule and an aliphatic monocarboxylic acid, and an epoxy resin having two or more epoxy groups in one molecule as necessary. , Hardener (B) and diluent (D)
Are simultaneously, or separately, stirred, dissolved or pulverized, mixed and dispersed while adding a heat treatment as necessary, and the conductive filler (C) is added to these mixtures to be mixed, stirred and dispersed. The apparatus for mixing, dissolving, dispersing, etc. is not particularly limited, but for example, a flask reaction kettle equipped with a stirrer, a heating device, a liquor machine, three rolls, a ball mill, a planetary mixer, etc. can be used. You may combine suitably.

In order to adhere a semiconductor element to a substrate such as a lead frame using the conductive resin paste of the present invention, first, the conductive resin paste is applied on the substrate by a dispensing method, a screen printing method, a stamping method or the like. Alternatively, the semiconductor element may be pressure-bonded and then heated and cured by using a heating device such as an oven or a heat block. Further, after the wire bonding process, the semiconductor device is completed by sealing by a usual method.

[0016]

EXAMPLES The present invention will be described in detail below with reference to examples. Example 1 0.05 g of benzyldimethylamine (reagent) was added to 50 g of trifunctional epoxy resin TACTIX-742 (trade name, manufactured by Dow Chemical Co.) and 9 g of caprylic acid (reagent) to prepare 1
Stir at 20 ° C., sample for a certain period of time, cool to room temperature when the reaction rate by acid value measurement with potassium hydroxide alcohol solution becomes 95% or more, and add 50 g of butyl cellosolve acetate (reagent) to this. Four
It heated at 0 degreeC and stirred, and the epoxy resin solution was obtained. To 30 g of this epoxy resin solution, 12.2 g of a phenol resin solution prepared by heating and dissolving 60 g of novolac phenol resin H-1 (trade name of Meiwa Kasei Co., Ltd.) and 40 g of butyl cellosolve acetate was added, and Silvest T was further added.
95 g of CG-1 (silver powder, trade name manufactured by Tokuriki Kagaku Kenkyusho) and 1.0 g of CUREZOLE 2PHZ (trade name of imidazole, manufactured by Shikoku Kasei) were added, and the mixture was kneaded using a likai machine and a three-roll mill to obtain a uniform conductive resin. I got a paste. The properties (viscosity, volume resistivity, adhesive strength at room temperature and 350 ° C., warpage of chips) of the obtained conductive resin paste were examined, and the results are shown in Table 1.

Examples 2 to 7 and Comparative Example 1 Each conductive resin paste was obtained in the same manner as in Example 1 except that the composition shown in Table 1 was used. Table 1 shows the measurement results of the characteristics.

[Table 1]

<Method of measuring characteristics> (1) Viscosity: Using an EHD type rotational viscometer manufactured by Tokyo Keiki Co., Ltd.
A 3 ° cone rotor was set and a measured value at 25 ° C and 0.5 rpm was obtained. (2) Volume resistivity: A conductive resin paste is applied on a slide glass so that the width is 2 mm and the thickness is 0.1 mm, and this is heat-cured in an oven at 180 ° C. for 1 hour, and the resistance is obtained using a Wheatstone bridge. Was measured, and the volume resistivity ρ _v was calculated by the following formula.

[Formula 1] ρ _v (Ω · cm) = R · W · d / L R: Measured resistance value (Ω) W: Width of sample (cm) d: Thickness of sample (cm) L: Distance between measuring terminals (Cm) (3) Bonding strength: Si-chip cut into 2 x 2 mm,
A conductive resin paste was used for pressure bonding on a silver-plated copper frame, followed by heat curing for 2 minutes in a heat block at 200 ° C. to obtain a test piece. The shear adhesive strength at the time of heating at room temperature and 350 ° C. was measured using a push-pull gauge (manufactured by Aiko Engineering Co., Ltd.). (4) Chip warp: A silicon chip cut into 5 × 13 mm was crimped onto a silver-plated copper frame using a conductive resin paste, and the chip warp was obtained when the chips were bonded in an oven at 180 ° C. for 1 hour. Roughness meter DEKTAK II
(Manufactured by SLOAN) using a scanning distance of 11
It was measured in mm. From Table 1, it is shown that the conductive resin paste of the present invention is excellent in conductivity, workability and adhesive strength, has little chip warpage, and has an excellent effect of relaxing thermal stress.

[0019]

According to the conductive resin paste of the present invention,
Since the thermal stress caused by the difference in the thermal expansion coefficient between the semiconductor element and the substrate such as the lead frame can be relaxed, the characteristic failure of the semiconductor element due to the chip crack or the stress distortion during the heat treatment in the semiconductor device assembling process can be prevented. Can be prevented. Further, since it is excellent in workability, curability and adhesiveness, it becomes possible to carry out a short-time curing treatment for a large chip, which has been difficult to apply with a conventional conductive resin paste.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuo Ichimura             Hitachi, Ichiba, Ibaraki Prefecture             Seikou Co., Ltd. Yamazaki Factory (72) Inventor Kimie Fujita             Hitachi, Ichiba, Ibaraki Prefecture             Seikou Co., Ltd. Yamazaki Factory

Claims (2)

[Claims] 1. A conductive resin paste containing (A) epoxy resin, (B) curing agent, (C) conductive filler and (D) diluent, wherein two epoxy resins (A) are contained in one molecule. A conductive resin paste which is a reaction product of the above epoxy resin having an epoxy group and an aliphatic monocarboxylic acid. 2. A semiconductor device obtained by bonding a semiconductor element and a substrate with the conductive resin paste according to claim 1 and then sealing the same.