JP2002105286A - Resin paste for semiconductor and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin paste for a semiconductor, which gives a cured product low in stress and reduces warping of a semiconductor element after cured. SOLUTION: The resin paste for the semiconductor is composed of (A) an epoxy resin containing a long chain alicycyclic epoxy resin of 20-80 wt.% in the total epoxy resin, (B) a metal complex, (C) a phenol compound, (D) a low stress agent and (E) a silver powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin paste for bonding a semiconductor element such as an IC or an LSI to a metal frame or the like.

[0002]

2. Description of the Related Art Recent remarkable developments in the electronics industry have evolved into transistors, ICs, LSIs, and ultra-LSIs. These semiconductor devices have rapidly increased the degree of circuit integration and have enabled mass production. With the widespread use of semiconductor products using semiconductor devices, improvement in workability and cost reduction in mass production have become important issues. Conventionally, it has been common practice to join a semiconductor element to a conductor such as a metal frame by an Au-Si eutectic method, and then seal it with a hermetic seal to obtain a semiconductor device. However, in view of workability and cost during mass production, a resin encapsulation method has been developed and is now generally used. Accordingly, a method using a solder material or a resin paste has been adopted as an improvement of the Au-Si eutectic method in the mounting step.

However, the solder method has drawbacks such as low reliability and easy contamination of the electrodes of the semiconductor element. Power transistors which require high thermal conductivity are disadvantageous.
It is used only for power IC elements. On the other hand, resin paste is superior in workability, reliability, etc. as compared with the soldering method, and its demand is rapidly increasing. Damage tends to increase, and a resin paste having low stress after curing has been demanded. With the diversification of semiconductor elements, there are various elements of various sizes. Particularly, large semiconductor elements have a risk of breaking if the stress of the paste is high. Conventionally, a low-stress agent and a long-chain resin are added,
A technique for reducing the warpage by reducing the elastic modulus is known, but with the diversification of semiconductor elements, it has become necessary to further reduce the elastic modulus. When a large amount of elastomer and long-chain resin is contained in the resin paste, the elastic modulus decreases, but the viscosity increases and the shear strength may decrease.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin paste in which a cured product of the resin paste has low stress and the warpage of the semiconductor element after curing is small.

[0005]

According to the present invention, there is provided an epoxy resin containing (A) a long-chain alicyclic epoxy resin represented by the general formula (1) in an amount of 20 to 80% by weight in all epoxy resins;
(B) The metal complex represented by the general formula (2), (C) a phenolic compound, (D) a low-stress agent and (E) silver powder are essential components. )
Is 0.2 to 20 parts by weight, component (C) is 3 to 20 parts by weight,
5 to 30 parts by weight of component (D), 220 to 8 of component (E)
This is a semiconductor resin paste which is 00 parts by weight and a semiconductor device manufactured using the resin paste.

Embedded image (N is an integer of 1 or more)

[0006]

Embedded image (M is a 1-3 valent metal atom)

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The general formula (1) used in the present invention
The long-chain alicyclic epoxy resin represented by has four or more carbon atoms between the cyclohexene oxide groups,
It has a feature of imparting flexibility, and it has been found that the elasticity of the cured paste is reduced by using the resin paste for a semiconductor. The long-chain alicyclic epoxy resin represented by the general formula (1) used in the present invention must contain 20 to 80% by weight of the total epoxy resin. If the content is more than 10% by weight, the curability deteriorates, which is not preferable. The other epoxy resin used in combination with the long-chain alicyclic epoxy resin represented by the general formula (1) is not particularly limited.
21 (Daicel Chemical Industries, Ltd.), styrene oxide, vinylcyclohexene dioxide, dicyclopentadiene dioxide, alicyclic diepoxy-adipate, or bisphenol A, bisphenol F, phenol novolak resin, cresol novolak resin, and epichlorohydrin. Aliphatic epoxy such as polyglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and heterocyclic epoxy such as diglycidyl hydantoin obtained by the reaction of An epoxy resin that reacts quickly is celloxide 2021, which is a bifunctional short-chain alicyclic epoxy. These may be used alone or as a mixture. The long-chain alicyclic epoxy resin represented by the general formula (1) can be obtained from Daicel Chemical Industries, Ltd. using celloxide (2081, 208).
It is commercially available as 3).

The metal complex (B) represented by the general formula (2) used in the present invention is acetylacetonate, which acts as a curing accelerator. Specifically, nickel (I) acetylacetonate, aluminum acetylacetonate, beryllium acetylacetonate, chromium (III) acetylacetonate, cobalt (II) acetylacetonate, cobalt (III) acetylacetonate, copper (II) ) Acetylacetonate, indium (III) acetylacetonate, iron (II) acetylacetonate, lithium (I) acetylacetonate, magnesium (II) acetylacetonate, manganese (II)
Examples include acetylacetonate and zinc (II) acetylacetonate. Preferred are aluminum acetylacetonate, cobalt (II) acetylacetonate, cobalt (III) acetylacetonate, and zinc (I
I) acetylacetonate and the like. The compounding amount of the metal complex (B) represented by the general formula (2) is preferably 0.2 to 20 parts by weight based on 100 parts by weight of the component (A). If the amount is less than 0.2 part by weight, the effect of promoting the curing is insufficient, and if the amount exceeds 20 parts by weight, the viscosity of the resin paste may be increased although the effect of promoting the curing is not so large.

[0009] The phenolic compound (C) used in the present invention acts as a curing agent for the epoxy resin and improves the adhesiveness and moisture resistance. The phenol compound (C) preferably has two or more active hydrogen groups per molecule which react with an epoxy group and contribute to crosslinking. For example, bisphenol A, bisphenol F, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, dihydroxydiphenyl ether, dihydroxybenzophenone, o-hydroxyphenol, m-hydroxyphenol, p-hydroxyphenol, biphenol, tetramethylbiphenol, ethylidenebisphenol, methylethylidenebis (methylphenol), cyclidene hexylidene An initial condensate obtained by reacting bisphenol or a phenol such as phenol, cresol, xylenol and formaldehyde with an acid catalyst; And acrolein, an initial condensate obtained by reacting a polyfunctional aldehyde such as glyoxal under an acid catalyst, or an initial condensate obtained by reacting a phenol such as resorcinol, catechol and hydroquinone with formaldehyde aldehyde under an acid catalyst. Condensates and the like may be mentioned, and these may be used alone or as a mixture. The compounding amount of the phenol compound (C) is preferably 3 to 20 parts by weight based on 100 parts by weight of the component (A) from the viewpoint of adhesiveness and moisture resistance. If it is less than 3 parts by weight, the curability is insufficient, and if it exceeds 20 parts by weight, the viscosity of the resin paste may increase, which is not preferable.

The low-stress agent (D) in the present invention has an effect of reducing the stress of the cured resin paste, and is not particularly limited. Examples thereof include polyisoprene, polybutadiene, 1,2-polybutadiene, and styrene-butadiene rubber. Acrylonitrile-butadiene rubber, polychloroprene, poly (oxypropylene), poly (oxytetramethylene) glycol, polyolefin glycol, poly-ε-caprolactone, silicone rubber, polysulfide rubber, fluorine rubber, and the like. Low stress agent (D)
Is 5 to 30 parts by weight based on 100 parts by weight of the component (A).
It is preferable that the amount be part by weight in terms of lowering the elastic modulus.
If the amount is less than 5 parts by weight, the elastic modulus increases, and if it exceeds 30 parts by weight, the viscosity of the resin paste extremely increases, which is not preferable.

The silver powder (E) used in the present invention imparts conductivity, and the content of ionic impurities such as halogen ions and alkali metal ions is preferably 10 ppm or less. The shape of the silver powder may be flakes, dendrites, spheres, or the like. The particle size of the silver powder to be used varies depending on the viscosity of the required resin paste, but usually the average particle size is preferably 2 to 10 μm, and the maximum particle size is preferably about 50 μm. In addition, a mixture of a relatively coarse silver powder and a fine silver powder may be used, and various shapes may be appropriately mixed and used. The blending amount of the silver powder (E) is preferably from 220 to 800 parts by weight based on 100 parts by weight of the component (A). If it is less than 220 parts by weight, the conductivity is insufficient, and if it exceeds 800 parts by weight, the viscosity of the resin paste may increase, which is not preferable.

In the resin paste of the present invention, additives such as a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a pigment, a dye, an antifoaming agent, a surfactant, and a solvent can be used as necessary. . As a method for producing the resin paste in the present invention, for example, there is a method in which each component is premixed, a paste is obtained using a three-roll or the like, and the paste is defoamed under vacuum.

The semiconductor device manufactured by using the semiconductor resin paste of the present invention has a low stress and therefore has little damage to the semiconductor element and is highly reliable. In particular, the effect is remarkable when used for a large-sized semiconductor element having a size of 6 mm ² or more. A known method can be used for manufacturing a semiconductor device using a resin paste for a semiconductor.

[0014]

EXAMPLES The present invention will be specifically described with reference to Examples. The mixing ratio of each component is part by weight. <Examples 1 to 7 and Comparative Examples 1 to 8> Each component having the composition shown in Tables 1 and 2 was mixed with silver powder, and kneaded with a three-roll mill to obtain a resin paste. After defoaming the resin paste at 2 mmHg for 30 minutes in a vacuum chamber, various performances were evaluated by the following methods. Table 1 shows the evaluation results.

<Raw materials used> Long chain alicyclic epoxy resin represented by the general formula (1):
Celloxide 2081 (manufactured by Daicel Chemical Industries, Ltd.)-Short-chain alicyclic epoxy resin represented by the formula (3): Celloxide 2021P (manufactured by Daicel Chemical Industries, Ltd.)

Embedded image ・ Epoxy resin used in combination with long-chain alicyclic epoxy resin; bisphenol F type epoxy resin

Metal complex in which M in formula (2) is aluminum: aluminum acetylacetonate (manufactured by Kawaken Fine Chemical Co., Ltd.) Phenol compound: bisphenol S (Tokyo Chemical Industry Co., Ltd.) Terminal carboxyl group Contained butadiene-acrylonitrile rubber: CTBN-1008-SP (manufactured by Ube Industries, Ltd .; hereinafter, referred to as CTBN) Compound (elastomer) obtained by adding propylene oxide to bisphenol A: BP-5P (manufactured by Sanyo Chemical Industries, Ltd.) Silver powder: flakes with a particle size of 0.1 to 50 μm and an average particle size of 3 μm

<Evaluation method> Viscosity: 25 ° C. using an E-type viscometer (3 ° cone);
The value at 5 rpm was measured and defined as viscosity. Adhesive strength: Using a resin paste, a 2 × 2 mm silicon chip was mounted on a silver frame and placed in an oven for 20 minutes.
Cured at 0 ° C. for 60 minutes. After curing, it was left for 72 hours in an 85 ° C./85% constant temperature bath, and the hot die shear strength at 250 ° C. before and after moisture absorption was measured using a mount strength measuring device. Warpage: A 6 × 15 mm silicon chip was mounted on a silver frame using a 30 μm thick resin paste, and cured in an oven at 200 ° C. for 60 minutes. After curing, the warpage of the chip was measured. Elastic modulus: 1x cured in oven at 200 ° C for 60 minutes
The tensile strength of a 13 cm strip sample at room temperature was measured to determine the elastic modulus.

[0018]

[Table 1]

[0019]

[Table 2]

In Examples 1 to 7, excellent resin pastes having high adhesive strength when heated, low warpage, and low elastic modulus were obtained. In Comparative Example 1, the die shear strength was low because only long-chain alicyclic epoxy was used, and in Comparative Example 2, warpage and elastic modulus were high because short-chain alicyclic epoxy was used. In Comparative Example 3, warpage and elasticity were high because no low stress agent was added, and in Comparative Example 4, the amount of addition was too large and the viscosity was high. In Comparative Example 5, the amount of aluminum acetylacetonate was small and the die shear strength was small, and in Comparative Example 6, the amount of aluminum acetylacetonate was large and the viscosity was too high. In Comparative Example 7, the amount of bisphenol S was small and the die shear strength was small, and in Comparative Example 8, the amount of bisphenol S was large and the viscosity was too high.

[0021]

The semiconductor device manufactured by using the semiconductor resin paste of the present invention has a low elastic modulus and a small warpage, so that the semiconductor element is less damaged and has excellent reliability.

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Claims (2)

[Claims] 1. An epoxy resin containing (A) a long-chain alicyclic epoxy resin represented by the general formula (1) in an amount of 20 to 80% by weight in all epoxy resins, and (B) an epoxy resin represented by the general formula (2). The metal complex, the (C) phenol compound, the (D) low stress agent and the (E) silver powder are essential components, and the component (B) is 0.2 to 20 parts by weight based on 100 parts by weight of the component (A). (C) 3 to 20 parts by weight, component (D) 5 to 30 parts by weight, and component (E) 220 to 800 parts by weight. Embedded image (N is an integer of 1 or more) (M is a 1-3 valent metal atom) 2. A semiconductor device manufactured using the resin paste for a semiconductor according to claim 1.