JPH09172127A - Lead frame and semiconductor device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent quality lead frame, which has a heat sink, maintains a stable function and reliability for a long time, and a semiconductor device using such a lead frame. SOLUTION: A lead frame is provided with a heat sink 4 which adheres at the bottom of a die pad 2 and dissipates heat. A plurality of nails 8 are formed on the heat sink and are lanced in the height direction. A die pad is fitted and mounted on the inner plane area, and the die pad is fitted by bending the leading edge of the tooth. The lead frame, which is provided with the heat sink and integrates the lead frame main body with the heat sink 4 by firm bonding, a semiconductor chip mounted on the die pad 2 by firm bonding and an inner lead are connected by bonding wire. The internal of the inner lead is package with a sealing material, so that a semiconductor device is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation plate-equipped lead frame in which a die pad of a lead frame main body is fitted and mounted and fixed by a plurality of claw pieces formed on the heat dissipation plate, and a semiconductor device using the same. .

[0002]

2. Description of the Related Art In recent years, as semiconductor integrated circuits have become more multifunctional and highly integrated, the semiconductor chip size and the die pad supporting the semiconductor chip have been increased in size, while the external size of the package has been reduced. Since the area ratio is expanded, the adhesion between the die pad and the sealing resin is poor, and the thermal expansion coefficient is different, peeling at the interface between the die pad and the sealing resin will occur if continuous thermal stress is applied by the heat generated by the semiconductor chip. The semiconductor chip is cracked, the package is cracked, etc., and the reliability of the semiconductor device is reduced.

Therefore, in a semiconductor device mounted with a chip having a large amount of heat generation such as a high-power semiconductor chip, as shown in FIG. 4, a strip-shaped thin plate made of an iron-nickel-based or copper-based metal material is stamped by a stamping method or A metal heat dissipation plate 4 having excellent thermal conductivity is fixed to the lower surfaces of the die pad 2 and the inner lead 3 of the lead frame 1 by a chemical etching process to form a desired shape, with an insulating adhesive 5 interposed therebetween. By incorporating the lead frame 1 having the heat dissipation plate 4 in the resin package 6, the heat generation of the semiconductor chip 7 is positively and efficiently discharged to the outside, and an excessive temperature rise inside the semiconductor device is suppressed. Generally, a method of maintaining a stable function without changing its characteristics is generally practiced.

[0004]

However, in the semiconductor device having the above-mentioned structure, when the lead frame body and the heat sink are fixed to each other, as described above,
An insulating adhesive material with a thermoplastic or thermosetting adhesive layer formed on both sides is used.This kind of adhesive material has hygroscopicity, and this property allows moisture to penetrate into the semiconductor device. Then, the heat history during the assembly process of the semiconductor device and the temperature rise accompanying the operation of the semiconductor device cause the moisture to evaporate and expand, generating bubbles and gas to cause peeling at the resin interface, package cracks, and internal leads. Cause the corrosion of the semiconductor device, and the functional characteristics and reliability of the semiconductor device are significantly impaired.

Further, since this kind of adhesive material is very expensive, it also causes a rise in manufacturing cost and product price. The present invention has been made in view of the above circumstances,
By preventing the moisture absorption phenomenon inside the semiconductor device due to the adhesive material and ensuring sufficient moisture resistance, it is possible to maintain stable function and reliability for a long period of time, and it has excellent quality. An object is to provide a semiconductor device.

[0006]

The features of the present invention for achieving the above object are that a die pad on which a semiconductor chip is mounted, a plurality of inner leads provided on the outer periphery of the die pad, and extending from the inner leads. In a lead frame including a lead frame main body portion having an outer lead and a heat radiating plate that adheres to a lower surface of the die pad to dissipate heat, a plurality of claw pieces are formed on the heat radiating plate in a height direction. The lead frame main body and the heat sink are fixed and integrated by fitting and mounting the die pad on the inner side surface area and fixing the die pad by bending the tip of the claw piece. The lead frame with a heat sink, the semiconductor chip fixedly mounted on the die pad, and the inner lead are connected by a bonding wire. Certain within the inner lead to the semiconductor device package by the sealing material.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a die pad is fitted and mounted on the inner side surface regions of a plurality of claw pieces formed on a heat dissipation plate and cut and bent in the height direction to bend the tip ends of the claw pieces. Since the lead frame main body and the heat sink are fixed and integrated by fixing the die pad with the die pad, no adhesive is used to fix the lead frame main body and the heat sink. Therefore, the phenomenon of moisture absorption inside the semiconductor device does not occur. Therefore, various problems such as peeling of the resin interface, package cracks, lead corrosion, etc., which have been caused by moisture absorption as in the past, do not occur.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view of a lead frame main body portion according to the present invention. The same figure (b) is the sectional view. FIG. 3C is a plan view of the heat sink. The same figure (d) is the sectional view. FIG. 2A is a plan view of a lead frame with a heat sink according to the present invention. The same figure (b) is the sectional view. FIG. 3 is a sectional view of a semiconductor device according to the present invention. FIG. 4 is a cross-sectional view of a semiconductor device using a lead frame with a heat sink according to the prior art. In addition, in the description of FIGS. 1, 2, and 3, the same or corresponding portions as those of the conventional technique are denoted by the same reference numerals.

In FIG. 1, a plurality of claw pieces 8 which are cut and bent in the height direction are formed on the upper surface side of the heat dissipation plate 4, and the lead frame main body is formed in an inner side surface area 9 of the claw pieces 8. Part 1
The die pad 2 of 0 is fitted and mounted. When the tip of the claw piece 8 is bent toward the center of the fitted die pad 2, the die pad 2 is fixed, and the lead frame body 10 and the heat sink 4 are fixedly integrated. It is possible to complete the lead frame 11 with a heat sink according to the present invention shown in FIG.

According to the present invention, when the lead frame body 10 and the heat sink 4 are fixed, the die pad 2 is placed and fixed by the claw pieces 8 formed on the heat sink 4 as described above. It is not necessary to use such an adhesive as described above, and peeling at the resin interface, package cracks, corrosion of internal leads, etc., which has occurred due to the hygroscopicity of the adhesive does not occur.

Further, the lead frame main body 10 and the heat radiating plate 4 are mounted and fixed by the claw pieces 8 in such a manner that a strong contact state can be maintained even when subjected to pressure during resin sealing or vibration such as movement. it can.

Next, in the semiconductor device according to the present invention shown in FIG. 3, the semiconductor chip 7 is fixedly mounted on the upper surface of the die pad 2 of the heat dissipation plate lead frame 11, and its terminals and a plurality of inner pads provided on the outer periphery of the die pad 2 are mounted. The lead 3 is connected via a bonding wire 12, and then the die pad 2 within the inner lead 3, the semiconductor chip 7 and the bonding wire 12 are connected.
Can be packaged with a sealing resin, and then the outer leads 13 projecting from the package 6 can be bent into a desired shape to complete.

In the above-described embodiment, the lead frame body 10 and the heat sink 4 are made of copper alloy, but the material and the combination are not limited to this. For example, the lead frame body 25 has a coefficient of thermal expansion relatively close to that of the semiconductor chip.
It can be manufactured with various combinations of materials, such as using a two-alloy material and using a material of copper alloy or aluminum alloy for the heat dissipation plate 4.

Further, in the above embodiment, the die pad 2 is fitted and mounted and fixed by the claw pieces 8 formed on the upper surface of the heat dissipation plate 4, but in this case, the inner surface of the claw pieces 8 is preliminarily set. If a conductor layer such as Ag paste is applied to the area 9,
The lead frame body 10 and the heat dissipation plate 4 are more firmly fitted to each other, a gap is not created between the die pad 2 and the heat dissipation plate 4 when they are fixed, and the conductivity to the heat dissipation plate 4 is reduced. The heat dissipation is also improved.

A plurality of claw pieces 8 formed on the heat dissipation plate 4
From the viewpoint of productivity and manufacturing cost, is formed by a general press working method, but the forming method is not limited to this, and it may be formed by, for example, a chemical etching working method. The chemical etching method is more effective when it is desired to form the claw pieces 8 without exerting stress on the plate 4.

[0016]

As described above, according to the present invention, the die pad is fitted and fixed on the inner side surface regions of the plurality of claw pieces formed on the upper surface of the heat dissipation plate and cut and bent in the height direction. As a result, the lead frame body and the heat dissipation plate are fixedly integrated with each other, and there is no need to use an adhesive as in the prior art. Therefore, in the semiconductor device using this lead frame with a heat sink, the moisture absorption phenomenon related to the adhesive does not occur, peeling of the resin interface, package cracks, corrosion of the internal leads, etc. do not occur, and sufficient moisture resistance is obtained. It is possible to obtain a semiconductor device having excellent quality capable of ensuring the reliability and maintaining the stable function and reliability for a long period of time.

[Brief description of the drawings]

FIG. 1A is a plan view of a lead frame main body according to the present invention. (B) It is sectional drawing of the lead frame main-body part by this invention. (C) A plan view of a heat sink according to the present invention. (D) It is sectional drawing of the heat sink according to this invention.

FIG. 2A is a plan view of a lead frame with a heat sink according to the present invention. (B) It is sectional drawing of the lead frame with a heat sink according to this invention.

FIG. 3 is a sectional view of a semiconductor device according to the present invention.

FIG. 4 is a cross-sectional view of a semiconductor device using a lead frame with a heat sink according to a conventional technique.

[Explanation of symbols]

 1, lead frame 2, die pad 3, inner lead 4, heat dissipation plate 5, insulating adhesive 6, resin package 7, semiconductor chip 8, claw piece 9, claw piece inner surface area 10, lead frame body 11, heat dissipation Lead frame with plate 12, bonding wire

Claims (3)

[Claims] A die pad on which a semiconductor chip is mounted;
A lead including a lead frame main body portion having a plurality of inner leads provided on the outer periphery of the die pad and outer leads extending from the inner leads, and a heat dissipation plate that adheres to the lower surface of the die pad to dissipate heat. In the frame, a lead frame, wherein a plurality of claw pieces are formed on the heat dissipation plate. 2. A plurality of claw pieces formed on a heat dissipation plate are cut and bent in a height direction, a die pad is fitted and mounted on an inner side surface region of the claw piece, and the die pad is bent by bending the tip end of the claw piece. The lead frame according to claim 1, wherein the lead frame body and the heat sink are fixed and integrated by fixing. 3. A die pad on which a semiconductor chip is mounted;
A lead including a lead frame main body portion having a plurality of inner leads provided on the outer periphery of the die pad and outer leads extending from the inner leads, and a heat dissipation plate that adheres to the lower surface of the die pad to dissipate heat. In the frame, a plurality of claw pieces are formed on the heat radiating plate and are cut and bent in a height direction, a die pad is fitted and mounted on an inner side surface region thereof, and the die pad is bent by bending the tip end of the claw piece. By fixing the lead frame main body portion and the heat dissipation plate, the semiconductor chip fixedly mounted on the die pad and the inner lead are connected by a bonding wire, and the inside of the inner lead is sealed. Semiconductor device packaged by material.