JPS58153338A - Semiconductor element - Google Patents

Abstract

PURPOSE:To obtain a semiconductor element having high reliability by bonding a semiconductor chip to a lead frame with resin having mainly bismaleimide and triazine resin monomer, and a composition which mixes modified resin made of epoxy resin with conductive or nonconductive powder. CONSTITUTION:Resin (a) having mainly bismaleimide and triazine resin monomer is mixed, for example, with resin (b) having more than three epoxy groups such as novolac epoxy resin, thereby improving the bonding strength at approx. 350 deg.C. In this case, the mixing ratio of the resins (a) and (b) is preferably by weight in the range of 5/95-70/30. If it is less than this range, the softening temperature decreases, thereby deteriorating the bonding strength, and if larger, the flexibility decreases. In mixing, the resin (b) is first dissolved in common solvent acetone, and the resin (a) is then dissolved. Further, 200-800pts.wt. of Ga or silica powder is added to the 100pts.wt. of modified resin, the mixture is sufficiently stirred, thereby completing the adhesive. According to this adhesive, the bonding or sealing of high reliability can be performed, and moisture resistance is particularly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a semiconductor element coated with resin, and particularly to a semiconductor element having excellent moisture resistance and reliability.

[Technical background of the invention]

Predetermined portions KIC, LS on the thin film substrate (lead frame)
The process of connecting semiconductor chips such as I is one of the important processes that affects the long-term reliability of the device. Traditionally,
The mainstream method for this has been the Au-8iO eutectic method, in which Si on the back surface of the chip is heat-pressed onto the Au plating surface on the lead frame.

However, with the popularity of precious metals, especially AuO, in recent years, resin molded semiconductor devices are rapidly shifting from the Au-8i eutectic method to methods that use all solder, methods that use conductive adhesives, etc.

[Background technology issue]

However, although some methods using solder have been put into practical use, it has been pointed out that the solder and solder balls may scatter and adhere to electrodes, etc., causing corrosion and disconnection. On the other hand, in the method of using conductive adhesive, epoxy resin mixed with Ag powder is usually used, and it has been partially put into practical use for about 10 years. Compared to the eutectic method of producing the synthesis, it was unsatisfactory. When using a conductive adhesive, it has advantages such as superior heat resistance compared to the NDA method, but on the other hand, the resin and its curing agent are made for bonding semiconductor elements. Therefore, the reliability of the device was inferior to that of the Au-8i eutectic method in many cases, which promoted corrosion of the Al electrode and caused disconnection. The purpose of the present invention is to provide a semiconductor device that uses the new adhesive that has been removed, which can significantly improve reliability, and reduce manufacturing costs by increasing the bonding speed.

[Summary of the invention]

The present invention uses a modified resin (4) consisting of (a) a resin whose main components are bismaleimide and triazine resin monomers, and ('b) an epoxy resin as an adhesive for bonding a semiconductor chip to a lead frame. or non-conductive powder ■
This is a semiconductor device using a modified resin composition consisting of.

The resin whose main components are (IL) bismaleimide and triazine resin monomer used in the present invention is represented by the general formula (1) in which Ar1 represents the same or different divalent aromatic group. Bismaleimide, dicyanate represented by the general formula %, and
) The dicyanate of the formula has 3 or more rings, 3J polymerized triazine, and 1 cyanate group at the end of the molecule.
.

For example, it has the following structural formula. tri, azine resin 0-Ar2~ (3) (wherein Ar2 in formulas (2) and (3) represents the same or different divalent aromatic group). An example of such a resin is BT Resin (trade name) manufactured by Mitsubishi Gas Chemical Co., Ltd., for example. BT resin is a heat-resistant addition-polymerizable thermosetting resin whose main ingredients are triazine resin (trade name) and bismaleimide developed by West German Nogyinil.
These resins are manufactured as follows.

5 (4) Triazine resin -> BT resin The molecular structure of BT resin after curing is estimated to be as follows.

H As such T resin, the following brands are commercially available, and any of them can be used in the present invention.

Furthermore, among the epoxy resins used in the present invention, examples of those that are industrially produced and can be effectively used in the present invention include geboxides of bisphenols such as those listed below. Shell Chemical Co., Ltd., Epikote
)827,828,834,1001゜1002,10
04,1007,1009゜Dow Chemical Company, DER3
30,3al,3a2,334,335.336,3
37, 660.

661, 662, 667, 668, 669゜Ciba Geigy, Araldite
)GY 250,260,280゜6071.6084
,6097,6099゜Jones Dabney Co., Ltd.
Epi-Rez 510,5101゜Dainippon Ink & Chemicals Co., Ltd., Epicron 810,1000,1010.30
100 (all above are product names).

Furthermore, in the present invention, by using a novolac epoxy resin having an average number of epoxy groups of 3 or more as the epoxy resin, it is possible to further improve the adhesive strength at high temperatures (350° C.).

The novolak epoxy resin used has a molecular weight of 5.
00 or more is suitable.

Examples of such novolak epoxy resins that are industrially produced include the following.

Ciba Geigy Co., Ltd. (Araldite)
)EPN1138. EPN1139. ECN127
3. ECN 1280° ECN1299° Dow Chemical Company, EEN 431, DEN438° Shell Chemical Company, Epjkote 152.154° Union Carbide Corporation, ERR-0
100, ERRBO447, ERLBO448゜(a)
The blending ratio of the resin whose main components are bis, maleimide and triazine resin monomer (b) and the epoxy resin (b) is preferably in the range of 5:95 to 70:30 (weight ratio). If the blending ratio of the resin (a) whose main components are bismaleimide and triazine resin monomer is less than the above range, the softening temperature of the resulting adhesive will be low, resulting in poor adhesive strength when heated; When the amount exceeds the range of , the flexibility of the resulting adhesive decreases.

When mixing (a) the resin whose main components are bismaleimide and triazine resin monomers and (ii) the epoxy resin of the present invention, they may be added and dissolved simultaneously in a common solvent for these resins. , it is desirable to first dissolve the latter in a solvent and then dissolve the former. Examples of the solvent include acetone, methyl ethyl ketone, dioxane, hexanone, benzene, toluene, solvent naphtha, industrial gasoline, cellosolve acetate, ethyl cellosolve, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and the like. These solvents may be used alone or in combination of two or more.

As the conductive or non-conductive powder, for example, Ag is used as the conductive powder, and silica is used as the non-conductive powder.

It is preferable to mix 200 to 800 parts by weight with respect to 100 parts by weight of a modified resin consisting of a resin whose main components are bismaleimide and a triazine resin monomer and an epoxy resin.

The semiconductor element of the present invention is produced by sufficiently mixing the above-mentioned modified resin and powder according to a conventional method, and then performing a kneading process using, for example, three rolls, and using the resulting mixture as an adhesive for bonding a semiconductor chip and a lead frame. After that, wire bonding may be performed, and then the semiconductor element may be sealed.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. The following parts refer to parts by weight unless otherwise specified.

Example 1 80 parts of Epikote 828 and BT2100 (resin 10 parts)
0%) at 120°C in a mixed solvent consisting of 110 parts of solvent naphtha and 7110 parts of cyclohexano.
.

A dissolution reaction was carried out for 1 hour to obtain a viscous brown modified resin.

A modified resin composition was prepared by mixing 55 parts of this modified resin and 75 parts of silver powder, and a semiconductor adhesive (A)' was obtained.

Example 2 100 parts of Epicote 827 was added to 90 parts of solvent naphtha.
part and cyclohexane))/9Q part at 90°C in a mixed solvent.
After dissolving, 10 parts of BT2170 (100% resin) was added and uniformly dissolved to obtain a viscous and transparent modified resin.

66 parts of this modified resin and 50 parts of silica powder were thoroughly mixed to obtain a modified resin composition, which was used as an adhesive for semiconductors (B).

Example 3 After dissolving 200 parts of ECN 1280 (manufactured by Ciba Geigy) in a solvent of 600 parts of cyclohexanone at 80°C,
Add 200 parts of BT2100 (100% resin) and add 1
A viscous and transparent modified resin was obtained by mixing at 00°C. 62 parts of this modified resin and 75 parts of silver powder were thoroughly mixed to obtain a modified resin composition, which was used as an adhesive for semiconductors (C).

Semiconductor adhesives obtained in Examples 1 to 3 (A), CB)
A semiconductor device was made using Q and a commercially available epoxy resin paste semiconductor adhesive, and its characteristics were measured and are shown in Table 1.

As shown in Table 1, the present invention was found to have excellent adhesive strength and hydrolysis resistance, particularly excellent moisture resistance, and to have sufficient reliability.

(1) 1 on the lead frame plated (NSD)
The silicone elements of swx1ar were glued and heated at the respective temperatures. Measured using a Spur gauge.

(2) 180℃ after curing the adhesive under the conditions in Table 1.
Value after heating extraction for 2 hours.

(3) Each semiconductor was subjected to a moisture resistance test (PCT) in water vapor at a temperature of 121°C and a pressure of 2 atm, and a humidity resistance test (bias-PCT) conducted in water vapor at a temperature of 120°C and a pressure of 2 atm by applying current at an applied voltage of 15 V DC. The device was tested and evaluated.

The number of semiconductor devices subjected to the above tests was 60 each,
The number of defects generated over time is shown in Table 1. The evaluation method is that the open or leakage current due to corrosion of the aluminum electrodes constituting the semiconductor element is 500% of the allowable value.
A rise above this level was determined to be defective.

Patent applicant: Toshiba Chemical Corporation

Claims (1)

[Scope of Claims] 1 (A) (a) a resin whose main components are hismaleimide and a triazine resin, cb) a modified resin consisting of an epoxy resin, and (i) a conductive or non-conductive powder. A semiconductor element using a modified resin composition consisting of the following as an adhesive for bonding a semiconductor chip and a lead frame. 2. The blending ratio of resin (a) and epoxy resin (a) is 5:
Claim 1 which is 95 to 70:30 (weight ratio)
Semiconductor device described in Section 1.