JPH0210860A - Lead frame for semiconductor device - Google Patents

Abstract

PURPOSE:To simply and easily prevent a gap caused by a shearing force operating at a boundary between the molding resin of a resin-sealed semiconductor device and leads by so forming that the direction of a roll mark formed on the surface of a conductive metal plate of a material by a rolling roller does not coincide with the longitudinal direction of the leads of a lead frame. CONSTITUTION:A lead frame for a semiconductor device is formed by first rolling a material conductive metal plate 1 to a rolled conductive metal plate 5 having a predetermined thickness by a rolling roller 2. In this rolling step, roll marks 4 having 0.6-9.0mum are formed on the surface of the plate 5 by roller scars 3 formed on the surface of the roll 2. The plate 5 is cut to match the width of the frame in its rolling direction. A desired lead frame 6 is manufactured of the plate 5 cut in the predetermined size by a metal mold or etching. In this case, the direction of the leads 6a of the frame 6 perpendicularly crosses the direction of the scars 4 formed on the plate 5.

Description

[Detailed Description of the Invention] [Summary] Regarding the use of roll marks made by a rolling roller on a conductive metal plate as a raw material used in lead frames for semiconductor devices, this invention works on the interface between the mold resin and the lead of a resin-encapsulated semiconductor device. The purpose of the present invention is to provide a lead frame for a semiconductor device that can simply and easily prevent the occurrence of gaps caused by shearing force, and includes a mounting part for a semiconductor chip and a lead frame that is enclosed in a package in the vicinity of the mounting part. A lead frame having a plurality of leads consisting of an inner lead and an outer lead protruding outside the package, the lead frame having a direction in which a roll mark is formed on the surface of a raw material conductive metal plate by a rolling roller and a lead frame. The structure is such that the longitudinal directions of the two do not coincide with each other.

[Industrial application field]

The present invention relates to a lead frame for a semiconductor device, and particularly to the use of roll marks caused by a rolling roller on a conductive metal plate as a raw material.

The remarkable progress of resin-encapsulated semiconductor devices in recent years is largely due to improved reliability due to improved moisture resistance. This has become possible by limiting the amount and reducing ionic impurities in the molding resin itself.

The three main routes for moisture infiltration are one through the interface between the mold resin and the leads of the lead frame, and the other through the bulk of the mold resin itself.

Those that penetrate through the interface are caused by improving the adhesion between the mold resin and the lead frame material by adding catalytic coupling materials and other ingredients, and those that penetrate through the mold resin itself are caused by hyper-crosslinking of the mold resin. We are taking measures to address the issue.

However, for substances that penetrate through the interface, there is a limit to the improvement of adhesion by chemical methods, and measures to improve adhesion by other methods are required.

Due to the above circumstances, in resin-encapsulated semiconductor devices,
There is a need for a lead frame for a semiconductor device that can limit the amount of moisture that reaches the wiring portion of the element forming surface of a semiconductor chip.

[Prior Art] A conventional lead frame for semiconductor devices will be explained with reference to FIG.

The conventional lead frame for semiconductor devices is first shown in Figure 3 (a).
The material conductive metal plate 21 is rolled by a rolling roller 22 as shown in
The conductive metal plate 25 is rolled into a rolled conductive metal plate 25 having a predetermined thickness.

This rolled conductive metal plate 25 is cut to match the width of the lead frame, as shown in FIG.

The rolled conductive metal plate 25 cut into predetermined dimensions in this way
As shown in FIG. 3(C), a desired lead frame 26 is manufactured using a mold or by etching.

In this case, roller scratches 23 formed in the direction of the lead frame 26 glued 26a and on the surface of the rolling roller 22 are
Therefore, the directions of the roll group 24 formed on the surface of the rolled conductive metal plate 25 are aligned.

[Problem to be solved by the invention]

In the conventional lead frame described above, the direction of the leads and the direction of the roll marks on the rolled conductive metal plate match, so when a resin-encapsulated semiconductor device is manufactured using such a lead frame, As shown in Figure 4,
When shrinkage force when the mold resin cools after molding or tensile force applied to the lead during the lead molding process acts on the interface between the lead and the mold resin, a gap is generated due to the shearing force acting on the interface between the mold resin and the lead. There was a problem.

In view of the above-mentioned circumstances, the present invention provides a lead frame for a semiconductor device that can simply and easily prevent the generation of gaps caused by shear forces acting on the interface between the mold resin and the leads of a resin-sealed semiconductor device. The purpose is to provide

[Means to solve the problem]

The above-mentioned problem is a lead frame that has a mounting part for a semiconductor chip, a plurality of leads consisting of inner leads enclosed in a package near the mounting part, and outer leads protruding outside the package, and the lead frame is rolled. This problem is solved by the lead frame for a semiconductor device according to the present invention, which is formed so that the direction of the roll marks formed by the roller on the surface of the raw conductive metal plate does not match the longitudinal direction of the leads of the lead frame.

[Effect]

That is, in the present invention, the lead frame is formed so that the direction of roll marks formed on the surface of the raw material conductive metal plate by the rolling roller does not match the longitudinal direction of the leads of the lead frame. When molded, the roll group formed on the surface of the lead at the interface between the mold resin and the lead increases physical adhesion,
Since it is possible to produce a so-called anchor effect, it is possible to expect the anchor effect without performing any special processing or treatment on the rolled conductive metal plate that is the raw material for the lead frame.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 1, and another embodiment with reference to FIG. 2.

A lead frame for a semiconductor device according to an embodiment of the present invention is manufactured by first rolling a raw conductive metal plate 1 using rolling rollers 2 into a rolled conductive metal plate 5 having a predetermined thickness, as shown in FIG. are doing.

In this rolling process, roll marks 4 of 0.6 to 9.0 μm are formed on the surface of the rolled conductive metal plate 5 due to roller scratches 3 formed on the surface of the rolling roller 2 .

As shown in FIG. 1(b), this rolled conductive metal plate 5 is
Cut in the rolling direction to match the width of the lead frame.

As shown in FIG. 1C, the rolled conductive metal plate 5 cut into predetermined dimensions is used to manufacture a desired lead frame 6 using a mold or by etching.

In this case, the direction of the leads 6a of the lead frame 6 and the direction of the roll marks 4 formed on the rolled conductive metal plate 5 are perpendicular to each other.

In a lead frame for a semiconductor device according to another embodiment of the present invention, as shown in FIG.
I have to.

In this case, as in the case of one embodiment, in this rolling process, the surface of the rolled conductive metal plate 15 has a 0.6
A roll mark 14 of ~9.0 μm is formed.

As shown in FIG. 2(b), this rolled conductive metal plate 15 is cut to match the width of the lead frame as in the conventional method.

The rolled conductive metal plate 15 cut into predetermined dimensions in this way
As shown in FIG. 2(L), a desired lead frame 16 is manufactured using a mold or by etching.

In this case, the continuous direction of the individual semiconductor chip mounting portions and the leads 16a constituting the lead fly 16 is different from that of the conventional example or the one embodiment.

With such a configuration, the width of the rolled conductive metal plate 15 perpendicular to the roll direction and the width of the lead frame 16 can be made to match, so that the width of the rolled conductive metal plate 15 that is continuous in the longitudinal direction can be made equal to the width of the lead frame 16. It becomes possible to manufacture the lead frame 16.

In all the embodiments of the present invention, the longitudinal direction of the leads of the lead frame is perpendicular to the roll marks on the rolled conductive metal plate formed by the roll scratches of the rolling roller, so that the mold resin and the leads are It is possible to expect an anchor effect against the shear force acting on the interface.

Note that in the above embodiment, the longitudinal direction of the lead of the lead frame is perpendicular to the roll marks on the rolled conductive metal plate formed by the scratches of the rolling roller, but this angle is limited to 906°. Instead, it is also possible to set it to any angle of about 45° or more.

The measurement results of the adhesion force acting between the mold resin and the lead frame are expressed as an index with the conventional value being 100, as shown in the adhesion index table below.

In addition, the temperature was 138.5℃ and the humidity was 85% for 1 hour.
The incidence of defects in the moisture resistance test for 01[ is as shown in the table of defect occurrence rates below.

Adhesion Index Table Defect Incidence Rate Table [Effects of the Invention] As is clear from the above explanation, according to the present invention, a special By utilizing the roll marks formed during the roll processing of rolled conductive metal sheets without performing any process, we can create an anchor effect against the shear force acting on the interface between the leads of the lead frame and the mold resin. There are significant economical and It is expected to have the effect of improving reliability and is extremely useful industrially.

In the figure, ■Material: conductive metal plate, 2 is a rolling roller; 3 is roller scratches, 4 is a roll mark, 5 is a rolled conductive metal plate; 6 is a lead frame, shows.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment according to the present invention in the order of steps. FIG. 2 is a diagram showing another embodiment according to the invention in the order of steps. FIG. 3 is a diagram showing the production of a conventional lead frame for a semiconductor device in the order of steps. FIG. 4 is a cross-sectional perspective view of a resin-sealed semiconductor device. (al Rolling process (C) Lead frame forming process An embodiment of the present invention is shown in process 11. Figure 1. Rolled conductive metal plate 5 40-ru marks (bl) Cutting process An embodiment of the invention is shown in process order. Fig. 1 fa+ Rolling step (a) Rolling step) Cutting step (Cl Lead frame forming step (bl Cutting step) Diagram showing another embodiment of the present invention in the order of the steps Manufacturing the conventional lead frame for a semiconductor device in the order of the steps 1925, 1939, 7th month, 2nd day, 1989 Patent No. 162199+a Lead frame forming process 2, Title of invention Process for manufacturing conventional lead frames for semiconductor devices Figure 3 shows the relationship between the person who makes the 3° correction of the lead frame for semiconductor devices and the person who makes the correction.

Claims (1)

[Claims] A lead frame having a mounting part for a semiconductor chip, and a plurality of leads including inner leads enclosed in a package close to the mounting part and outer leads protruding outside the package, the lead frame having a rolling roller to reduce the conductivity of the raw material. 1. A lead frame for a semiconductor device, wherein the lead frame is formed so that the direction of roll marks formed on the surface of a flexible metal plate does not coincide with the longitudinal direction of the leads of the lead frame.