JPH04300984A - Electrically conductive resin paste and semiconductor device - Google Patents

Abstract

PURPOSE:To provide an electrically conductive resin paste, useful for bonding a semiconductor element such as IC and LSI to a substrate such as a lead frame and excellent in stress relaxation properties. CONSTITUTION:An electrically conductive resin paste containing (a) an epoxy resin, (b) a curing agent, (c) an electrically conductive filler and (d) a curing accelerator. The aforementioned curing agent (b) is a product of reaction between a phenolic resin and a dimethylsiloxane compound having epoxy group. Furthermore, a semiconductor device is prepared by bonding a semiconductor element to a substrate with the above-mentioned 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 for bonding semiconductor elements such as ICs and LSIs to substrates such as lead frames, and a semiconductor device using the same.

0002

2. Description of the Related Art In recent years, conductive resin paste has been mainly used for bonding (die bonding) between semiconductor elements and lead frames. However, due to the diversification of sealing forms as the applications of semiconductor devices expand, the problem of thermal stress due to a mismatch in linear expansion coefficient between the semiconductor device and the lead frame material has become apparent. In order to solve this problem, a method using carboxylic acid-terminated polybutadiene-modified epoxy resin (Japanese Unexamined Patent Publication No. 6
2-199669), a method using epoxidized polybutadiene (JP 63-161015), a method using a dimethylsiloxane compound having an amino group or an alcohol group (JP 63-10104)
etc. are being carried out.

0003

[Problems to be Solved by the Invention] However, in each of the above methods, since the molecular weight of the carboxylic acid-terminated polybutadiene-modified epoxy resin is large, the coating workability of the conductive resin paste is poor, and the curability of the epoxidized polybutadiene is poor. Due to the low temperature, it is difficult to cure in a short time, resulting in poor productivity, and the poor compatibility between the dimethylsiloxane compound and epoxy resin causes separation during storage.The problem of thermal stress is not fully resolved. It has not been. The present invention provides a conductive resin paste that does not have the above-mentioned drawbacks and has excellent workability, hardenability, and compatibility, and a semiconductor device using the same.

0004

[Means for Solving the Problems] The present invention comprises (a) an epoxy resin, (b) a curing agent, (c) a conductive filler, and (d)
) In a conductive resin paste containing a curing accelerator, (b
) A conductive resin paste whose curing agent is a reaction product of a phenol resin and a dimethylsiloxane compound having an epoxy group, and a semiconductor device in which a semiconductor element is bonded to a substrate using the conductive resin paste.

The dimethylsiloxane compound having an epoxy group used in the present invention has the general formula

α,ω-bis(3-glycidoxypropyl)polydimethylsiloxane represented by
L-9906, TSL-9946, TSL-9986 (
Manufactured by Toshiba Silicone Co., Ltd.) General formula

The dimethylsiloxane compound represented by [Chemical formula 2], trade names include, for example, TSF4730, XF42-301, and XF3.
965 (manufactured by Toshiba Silicone Co., Ltd.) General formula

The trade name of the dimethylsiloxane compound represented by the following formula is, for example, TSL-9905 (manufactured by Toshiba Silicone Co., Ltd.). From the viewpoint of thermal stress absorption and workability, a low molecular weight dimethylsiloxane compound having two epoxy groups in one molecule is preferred.

The epoxy resin used in the present invention is not particularly limited, but compounds having two or more epoxy groups in one molecule are preferred from the viewpoint of curability. Examples of such epoxy resins include phenol novolac epoxy resins, such as N-730S (trade name, manufactured by Dainippon Ink and Chemicals Co., Ltd.);
Quatrex-2010 (product name manufactured by Dow Chemical Company)
, cresol novolac epoxy resins such as YDCN
-702S (product name manufactured by Toto Kasei Co., Ltd.), EOCN-100
(trade name manufactured by Nippon Kayaku Co., Ltd.), bisphenol F type epoxy resin, such as YDF-170 (trade name manufactured by Toto Kasei Co., Ltd.),
EXA-830 (trade name manufactured by Dainippon Ink Chemical Industries, Ltd.),
Bisphenol AD type epoxy resin, e.g. R-171
0 (trade name manufactured by Mitsui Petrochemical Co., Ltd.), bisphenol A-type epoxy resins, such as AER-X8501 (trade name manufactured by Asahi Kasei Industries, Ltd.), YL-980 (trade name manufactured by Yuka Shell Epoxy Co., Ltd.), trifunctional epoxy resins, such as EPPN-501
HL (product name manufactured by Nippon Kayaku Co., Ltd.), TACTIX-742 (
(trade name manufactured by Dow Chemical Company), VG-3101 (trade name manufactured by Mitsui Petrochemical Company), tetrafunctional epoxy resin, e.g. 103
1S (trade name manufactured by Yuka Shell Epoxy Co., Ltd.), 1,6-naphthalene skeleton epoxy resin, such as HP-4032 (trade name manufactured by Dainippon Ink & Chemicals Co., Ltd.), alicyclic epoxy resin,
For example, EHPE-3150 (trade name manufactured by Daicel Chemical Industries, Ltd.), amine type epoxy resin, such as ELM-100 (
(trade name manufactured by Sumitomo Chemical Co., Ltd.), YH-434L (trade name manufactured by Toto Kasei Co., Ltd.), triazine ring skeleton epoxy resin, such as TE
Examples include PIC (product name manufactured by Nissan Chemical Co., Ltd.). These may be mixed and used as appropriate.

[0007] The phenolic resin used in the present invention is as follows:
Examples include phenol novolac epoxy resins, such as H-1 (trade name, manufactured by Meiwa Kasei Co., Ltd.), and phenol aralkyl resins, such as XL-225 (trade name, manufactured by Mitsui Toatsu Chemical Co., Ltd.).

In the present invention, the phenol resin and the dimethylsiloxane compound having an epoxy group are blended so that the ratio of hydroxyl equivalent/epoxy equivalent is 1.
It is preferable to set the ratio to 0/0.1 to 0.6.

[0009] The reaction between the phenol resin and the dimethylsiloxane compound having an epoxy group can be carried out by mixing them, adding an appropriate catalyst and diluent, melting or dissolving the mixture at a temperature of 100 to 150°C, and stirring the mixture. . Examples of catalysts include benzyldimethylamine and triphenylphosphine, which are used to cause the reaction between the phenol resin and the dimethylsiloxane compound having an epoxy group to occur at low temperatures and in a short time. A diluent is also used to lower the viscosity and make the reaction product easier to handle. Examples of diluents include ethyl cellosolve, butyl cellosolve, cellosolve acetate, butyl cellosolve acetate, ethyl carbitol, ethyl carbitol acetate, butyl carbitol, butyl carbitol acetate, ethylene glycol diethyl ether, ethylene glycol dibutyl ether (manufactured by Tokyo Kasei Co., Ltd.), etc. Organic solvent, phenyl glycidyl ether (PGE, manufactured by Nippon Kayaku Co., Ltd.), P-(s
ec-butyl) phenyl glycidyl ether (PP10
1. Toto Kasei Co., Ltd. trade name), o-(sec-butyl)phenyl glycidyl ether (YED-122, Yuka Shell Epoxy Co., Ltd. trade name), alkyl glycidyl ether (ED-502, Asahi Denka Kogyo Co., Ltd. trade name) ), 1,6-hexadiol glycidyl ether (ED-503, trade name manufactured by Asahi Denka Kogyo Co., Ltd.), 3-glycidoxypropyltrimethoxysilane (KBM-403, trade name manufactured by Shin-Etsu Chemical Co., Ltd.)
, 3-glycidoxypropylmethyldimethoxysilane (
TSL-8355, Toshiba Silicone Co., Ltd. product name), 1-
(3-glycidoxypropyl)-1,1,3,3,3-
Pentamethyldisiloxane (TSL-9905, trade name manufactured by Toshiba Silicone Co., Ltd.), 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane (LS-7970, Shin-Etsu Chemical) Examples include reactive diluents with epoxy groups, such as (trade name) manufactured by the company.

[0010] The conductive filler used in the present invention includes:
Examples include aluminum, copper, gold, nickel, silver, iron, stainless steel, etc., but silver powder containing less ionic impurities such as halogen ions and alkali metals is preferred. The conductive filler may have a flake shape, a dendritic shape, a spherical shape, etc., and these may be appropriately mixed and used.

Examples of the curing accelerator used in the present invention include dicyandiamide (SP-10, trade name manufactured by Nippon Carbide Co., Ltd.), dihydrazide compounds (ADH, IDH, SD
H, N-12, Nippon Hydrazine Kogyo Co., Ltd. trade name), triphenylphosphine (TPP), tetraphenylboron salts (EMZ K, TPPK, Hokko Chemical Co., Ltd. trade name),
Tertiary amines such as benzyldimethylamine and their salts (DBU, U-Cat 5002, 102, 106
, 830, 340, all product names manufactured by Sun-Apro),
Imidazole (Curezole 2MZ, 2E4MZ, C
11Z, C17Z, 2PZ, 2P4MZ, 2EZ, 2I
Z, 2MZ-OK, 2PZ-OK, 2PHZ, 2P4M
HZ, 2PHZ-CN, 2P4MHZ-CN (all product names manufactured by Shikoku Kasei Co., Ltd.). These may be mixed and used as appropriate.

In the present invention, the amount of the reaction product of the phenol resin and the dimethylsiloxane compound having an epoxy group, which is used as the curing agent (b), is determined from the viewpoint of curability and cured physical properties. It is preferable to use the curing agent so that the amount of hydroxyl groups in the curing agent (b) is in the range of 0.6 to 1.5 equivalents. Used in the present invention (
d) From the viewpoint of curability and storage stability, the blending amount of the curing accelerator is 0.5 per 100 parts by weight of (a) epoxy resin.
It is preferable to set it as 30 parts by weight.

A diluent is used as necessary to adjust the viscosity of the conductive resin paste and improve workability. As the diluent, those mentioned above are used. The amount of diluent to be mixed is determined from the viewpoint of workability and stability of the conductive resin paste (
The amount is preferably 800 parts by weight or less based on 100 parts by weight of the total amount of a) epoxy resin and (b) curing agent. The amount of (c) conductive filler used in the present invention is 1 part by weight per 100 parts by weight of the total amount of (a) epoxy resin and (b) curing agent.
It is preferable to set it as 00-1000 parts by weight.

The conductive resin paste of the present invention contains adhesion improvers such as silane coupling agents and titanium coupling agents, wetting improvers such as nonionic surfactants and fluorine surfactants, and silicone oil. Antifoaming agents can be added as appropriate.

The conductive resin paste of the present invention has (a
) A predetermined amount of epoxy resin is mixed with a predetermined amount of diluent if necessary, mixed with heating if necessary, stirred and dissolved, and the predetermined amount of varnish obtained has phenolic resin and epoxy groups. (b) curing agent, (c) conductive filler, (d) which is a reaction product with a dimethylsiloxane compound;
) Add the curing accelerator and additives such as diluents and coupling agents added as necessary, all at once or in parts, and use a suitable combination of dispersing machines such as a stirrer, sieve, three-roll mill, or ball mill. It can be obtained as a uniform paste by kneading or dissolving it.

The semiconductor device of the present invention is obtained by bonding a semiconductor element to a base material such as a lead frame using the conductive resin paste of the present invention. , a semiconductor element is mounted thereon, and then heated and cured in an oven or on a heat block, and then sealed with resin using a conventional method. As the substrate, a metal frame such as copper or 42-alloy, a ceramic substrate, an organic substrate such as a glass epoxy substrate, etc. are used.

[0017]

[Operation] Since the conductive resin paste of the present invention has a low elastic modulus after curing, the conductive resin paste can be used to reduce thermal stress applied to a semiconductor element bonded to a copper frame or the like.

[0018]

[Examples] The present invention will be explained below with reference to Examples. Note that "parts by weight" are by weight unless otherwise specified. Example 1 Phenol novolak resin H-1 (trade name manufactured by Meiwa Kasei Co., Ltd.) 50 parts, dimethylsiloxane compound having an epoxy group, TSL-9906 (trade name manufactured by Toshiba Silicone Co., Ltd.) 2
0 parts, butyl cellosolve acetate 30 as diluent
The mixture was mixed and reacted at 120° C. for 2 hours in the presence of 0.1 part of triphenylphosphine as a catalyst to obtain a reaction product of a phenol novolak resin and a dimethylsiloxane compound having an epoxy group. 10 parts of this reactant, 15 parts of a heated solution of 60 parts of phenol novolak epoxy resin N-730S (trade name, manufactured by Dainippon Ink Chemical Industries, Ltd.) in 40 parts of butyl cellosolve acetate as a diluent, curing accelerator, triphenylphosphine 1 part TPP (trade name manufactured by Hokuko Chemical Co., Ltd.), diluent, 3-glycidoxypropyltrimethoxysilane, 4 parts KBM-403 (trade name manufactured by Shin-Etsu Chemical Co., Ltd.), silver powder, TCG-1 (trade name manufactured by Tokuriki Chemical Co., Ltd.) name) 7
0 parts was added and kneaded using a three-roll mill and a miller to obtain a uniform conductive resin paste.

Example 2 Dimethylsiloxane compound TSL-9 in Example 1
A uniform conductive resin paste was obtained according to the method of Example 1, replacing 906 with TSL-9946 (trade name, manufactured by Toshiba Silicone Co., Ltd.).

Example 3 Dimethylsiloxane compound TSL-9 in Example 1
A uniform conductive resin paste was obtained according to the method of Example 1, replacing 906 with TSL-9986 (trade name, manufactured by Toshiba Silicone Co., Ltd.).

Example 4 Phenol novolak epoxy resin N in Example 1
-730S cresol novolak resin YDCN-70
A uniform conductive resin paste was obtained according to the method of Example 1 except that 2S (trade name, manufactured by Toto Kasei Co., Ltd.) was used.

Example 5 Phenol novolac epoxy resin N in Example 1
-730S to bisphenol F type epoxy resin EXA-
830 (trade name, manufactured by Dainippon Ink and Chemicals) and followed the method of Example 1 to obtain a uniform conductive resin paste.

Example 6 Phenol novolac epoxy resin N in Example 1
-730S to bisphenol AD type epoxy resin R-1
A uniform conductive resin paste was obtained in accordance with the method of Example 1 except that 710 (trade name, manufactured by Mitsui Petrochemicals, Inc.) was used.

Example 7 Phenol novolac epoxy resin N in Example 1
-730S as bisphenol A epoxy resin AER-
A uniform conductive resin paste was obtained according to the method of Example 1 except that X8501 (trade name, manufactured by Asahi Kasei Industries, Ltd.) was used.

Example 8 Phenol novolak epoxy resin N in Example 1
-730S to trifunctional epoxy resin TACTIX-742
(trade name manufactured by Dow Chemical Company) and followed the method of Example 1 to obtain a uniform conductive resin paste.

Example 9 Phenol novolak epoxy resin N in Example 1
-730S was replaced with trifunctional epoxy resin VG-3101 (trade name, manufactured by Mitsui Petrochemicals, Inc.) and a uniform conductive resin paste was obtained according to the method of Example 1.

Comparative Example 1 10 parts of phenol novolac resin H-1 (trade name manufactured by Meiwa Kasei Co., Ltd.) dissolved by heating in 40 parts of butyl cellosolve acetate as a diluent and phenol novolac epoxy resin N-730S (Dainippon Ink Co., Ltd.) 15 parts of a solution obtained by heating and dissolving 60 parts of Kagaku Kogyo Co., Ltd. (trade name) in 40 parts of butyl cellosolve acetate as a diluent, curing accelerator, 1 part of triphenylphosphine (Hokuko Kagaku Co., Ltd. trade name), diluent 3-glyside 4 parts of xypropyltrimethoxysilane KBM-403 (trade name manufactured by Shin-Etsu Chemical Co., Ltd.), silver powder, T
70 parts of CG-1 (trade name, manufactured by Tokuriki Chemical Co., Ltd.) was added and kneaded using a three-roll mill and a sieve to obtain a uniform conductive resin paste.

Comparative Example 2 Phenol novolac epoxy resin N in Comparative Example 1
-730S to bisphenol F type epoxy resin EXA-
830 (trade name, manufactured by Dainippon Ink & Chemicals) and followed the method of Comparative Example 1 to obtain a uniform conductive resin paste. The properties shown in Table 1 were tested for the conductive resin paste obtained above.

*1. The viscosity (poise) at 25° C. was measured using an EHD rotational viscometer manufactured by Tokyo Keiki Co., Ltd. *2. The obtained conductive resin paste was applied onto a silver-plated copper lead frame, a 2 mm x 2 mm silicon chip was placed thereon, pressure bonded, and cured at various temperatures and times. The shear adhesive strength (kg/chip) at room temperature and the shear adhesive strength (kg/chip) at 350° C. of this cured sample were measured using a push-pull gauge (Eiko Engineering Co., Ltd.). *3. A conductive resin paste was applied to a silver-plated copper lead frame, and a 5 mm x 13 mm silicon chip was mounted and pressure-bonded, followed by heating and curing at 180° C. for 1 hour. Chip warpage (μm) at the center of the chip (11 mm along the length of the chip excluding 1 mm at both ends) was measured using a surface roughness meter DEKTAKII (SLOAN). *4. A conductive resin paste was applied to a Teflon plate to a uniform thickness and cured in an oven at 180°C for 1 hour. Grind the hardened sample. 10 g of the pulverized material was placed in a pressure-resistant Teflon bottle together with 50 g of ion-exchanged water, shaken, and then placed in an oven at 120° C. for 20 hours to extract impurities in the conductive resin paste. Chloride ion concentration in extracted water (ppm
) was measured using ion chromatography (Dionex). Table 1 shows that in the Examples in which a reaction product of a phenol novolak resin and a dimethylsiloxane compound having an epoxy group was used as a curing agent, stress was reduced and chip warpage was reduced compared to the Comparative Examples.

The above results are shown in Table 1.

[0031]

[Table 1]

[0032]

[Effect of the invention] The conductive resin paste of the present invention can be applied to metal frames, ceramic substrates, organic substrates, etc. for IC, LSI, etc.
It can be used to bond semiconductor devices such as copper frames and silicon chips, and prevents chip cracks during heat treatment during the assembly process of ICs, etc. due to the difference in thermal expansion coefficient between the copper frame and the silicon chip, and prevents characteristic defects of ICs etc. due to chip distortion. be able to. It is an excellent conductive resin paste that has excellent stress relaxation properties, which have not been sufficiently obtained in the past, and also has excellent curability, so it can be cured in a short time.

Claims (3)

[Claims] Claim 1: (a) an epoxy resin, (b) a curing agent,
(c) A conductive resin paste containing a conductive filler and (d) a curing accelerator, wherein the (b) curing agent is a reaction product of a phenol resin and a dimethylsiloxane compound having an epoxy group. 2. The conductive resin paste according to claim 1, wherein the dimethylsiloxane compound having an epoxy group is a dimethylsiloxane compound having a molecular weight of about 100% and having two epoxy groups in one molecule. 3. A semiconductor device comprising a semiconductor element bonded to a substrate using the conductive resin paste according to claim 1.