JPS63211661A - Lead frame - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lead frame used in a resin-sealed semiconductor device.

[Prior art]

Previously proposed lead frames of this type include:
In the lead frame 1 shown in FIG. 3, the tab lead 8 for connecting the tab 5 to the outer frame 2 is used to firmly bond the semiconductor chip 6 to the tab 5. The tab lead 8 curves upward as shown in FIG. 2(b) due to thermal expansion caused by the heat treatment when the chip 6 is mold-sealed with the resin body 1O, so that the electrode lead 4 and the chip There is a problem in that the wire 7 connecting the electrode on the tab 5 or the tab lead 8 contacts the tab 5 or the tab lead 8, causing a short circuit.

In order to deal with such problems, as shown in FIGS. 4 and 5, a strain-absorbing through-hole 9 is provided at the connection portion of the tab lead 8 with the outer frame 2 to absorb the strain of the tab lead 8.
Attempts have already been made to arrange connecting portions 9a and 9b on both sides of the through hole 9 symmetrically with respect to the central axis of the tab lead 8 to prevent displacement of the tab 5 in the horizontal direction on the plane (for example, Japanese Patent Laid-Open No. 51 (Refer to Publication No.-29086). In addition, the fourth
In the figure, numeral 3 denotes a frame that is connected to the outer frame and is generally called a "dam" to prevent resin from flowing.

[Invention or problem to be solved]

However, as mentioned above, the strain absorbing parts (9, 9a).

The lead frame provided with 9b) has the disadvantage that it cannot sufficiently cope with the miniaturization of the package.

That is, when downsizing the resin package, the lead frame 1 also needs to be downsized, and for this purpose, the outer frame 2 must be downsized.
Although it should be possible to bring the lead 4 closer to the tab 5 and the lead 4 closer to the tab lead 8, the arrangement of the strain absorbers described above acts to prevent these.

It is an object of the present invention to provide an improved lead frame that eliminates these drawbacks.

[Means to solve the problem]

In order to achieve this object, the present invention has a structure in which the semiconductor depth is divided between the tab to which the semiconductor chip is to be fixed and the tab lead connected to the outer frame, with a part of the tab lead being branched to be narrower than the width of the tab. A lead frame characterized by having a tab lead through hole.

〔Example〕

FIG. 1 shows a lead frame according to an embodiment of the present invention, and the same parts as in FIGS. 4 and 5 are given the same reference numerals. In FIG. 4, a strain-absorbing through hole 9 is provided at the connecting portion between the tab 5 to which the semiconductor chip 6 is to be fixed and the tab lead 8, and the connecting portions 9a and 9b on both sides of the through hole 9 are connected to the tab lead 8. They are arranged symmetrically about the central axis. Then, around the tab 5, there are a number of electrode lead-out boards 4 in the same manner as in the case of FIG.
is located.

According to the above configuration, since the strain absorbing parts (9, 9a, 9b) are provided on the tab side, it is easy to arrange the outer frame close to the tab, and the electrode lead is arranged close to the tab lead. This makes lead frames smaller and easier to use.
In other words, it becomes possible to easily cope with downsizing of the package.

For this reason, as shown in FIG. 2, another embodiment of the present invention:
A resin-sealed IC in which electrode leads 4 protrude from all sides of a sealing resin body 10 constituting a package.
It is very useful for improving packaging density in such applications.

As described above, according to the present invention, the distortion of the tab lead can be absorbed to prevent the bending of the tab lead, and the shift of the tab position can be prevented due to the symmetry of the connecting portion, without hindering the miniaturization of the package. It is.

In addition, according to the present invention, the resin enters the strain-absorbing through-hole, and as a result, the resin sticks well near the tab, reliably preventing water from entering the chip surface, and improving moisture resistance. There is also an improvement effect.

Furthermore, as is clear from FIG. 1, since the connecting portions on both sides of the through hole are formed narrower than the width of the tab, it is possible to secure an area where the lead tips can approach the chip.

In the above embodiment, the strain absorbing section is provided corresponding to two tab leads, but it is also possible to provide the strain absorbing section corresponding to at least one tab lead. In addition, the strain absorbing through hole 9 and the connecting portions 9a on both sides thereof
, 9b may have a shape other than that shown in the drawings as long as the symmetry with respect to the tab lead 8 is satisfied.

[Brief explanation of the drawing]

FIG. 1 is a top view of essential parts of a lead frame according to an embodiment of the present invention. FIG. 2 is a schematic top view of a resin-sealed IC using a lead frame according to another embodiment of the present invention. Figures 3 (a) and (b) are for explaining the problems of conventional lead frames; (a) is a schematic top view;
(b) is a cross-sectional view taken along line BB in figure (a). FIG. 4 is a top view of a lead frame designed to address the above problem. FIG. 5 is a partial top view for explaining the action of the strain absorbing section of the lead frame shown in FIG. 4. FIG. DESCRIPTION OF SYMBOLS 1...Lead frame, 2...Outer frame, 3...Dam, 4...Lead for electrode extraction, 5...Tab, 6...
IC chip. 7... Connection wire, end... tab lead, 9... through hole for strain absorption, 9a, 9b... connecting part, 10...
・Resin body for sealing. 1 (2) Palan 5 (α) 14 Figure 2 Mouth (b) Palette S En

Claims (1)

[Claims] 1. A lead frame characterized in that a tab lead through hole is provided between a tab to which a semiconductor chip is to be fixed and a tab lead connected to an outer frame by branching a part of the tab lead to be narrower than the width of the tab.