JPS62119950A - Lead frame for semiconductor device - Google Patents

Abstract

PURPOSE:To prevent short-circuiting between leads by a method wherein necking-provided half holes or protrusions are formed on the sides, nearer to as island, of tie bars and outer frames. CONSTITUTION:Necking-provided protrusions 6 are formed on the sides, nearer to an island 2, of tie bars 3 between leads 4, and necking-provided half holes 5 are formed on the inner sides of outer frames 1a, 1b. In this design, any plating transferred to a sealing-resin surface during its contact with the sides of the tie bars 3 and outer frames 1a, 1b does not cause short-circuiting. No short-circuiting occurs because part of plating-contaminated resin is removed by neck portions of half holes 5 and protrusions during a process of removing the tie bars 3 and outer frames 1a, 1b and any plating retained in a resin section 10 has both ends of a plated layer 11 removed between leads 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lead frame for a semiconductor device used for lead attachment and resin-sealing assembly of a tree-encapsulated semiconductor device.

[Conventional technology]

Figure K2 is a plan view showing one unit section of a conventional lead frame in which a semiconductor element is fixed and sealed with resin.

In the figure, each unit section of a lead frame, in which a large number of elongated unit sections are connected in a tape-like manner by upper and lower outer frames 7a and 7b, has a semiconductor element mounted on an island 2 supported by hanging leads on outer frames 7a and 7b. 8 are fixed to each other, and a large number of leads 4 are connected to each other by tie bars 13.
are arranged so that their inner ends are gathered around the island 2. After connecting the inner end of the lead 4 and the electrode pad of the semiconductor element 8 with the bonding wire 9, the resin (
10 (shown with a dotted line).

[Problem that the invention seeks to solve]

In the lead frame as described above, the inner end of each lead 4 and the island are used to fix the element 8 to the island 2 and to connect the inner end of the lead and the electrode pad of the semiconductor element with a bonding wire. 2 is partially plated with Au or Ag. However, during partial plating, a considerable plating layer is also deposited on the tie bars 13 and the side surfaces of the outer frames 7a and 7b. The plating layer adhering to this side surface is deposited due to oozing of the plating solution, etc., and therefore does not adhere well to the base and easily peels off. Therefore, when sealing with resin 10, the plating layer on the tie bar side surface and the outer frame side surface is transferred and attached to the sealing resin that leaks out of the resin sealing range from the gap in the lead frame plate thickness. This has the drawback that after the tie bars and outer frame are cut and removed, the leads may be short-circuited for some time.

[Means for solving problems]

In order to solve the above problem, in the present invention, after the tie bars and outer frame are separated, the plating layer on the side surface facing the island is applied to the sealing resin in a manner that short-circuits between the leads. In order to prevent this from remaining, semi-holes or protrusions with constrictions are provided on the side surfaces of the tie bar and outer frame.

〔Example〕

Next, the present invention will be explained using examples.

FIG. 1 is a plan view showing one unit section of an embodiment of the present invention. In the figure, an island 2 to which a semiconductor element is fixed
are supported by the outer frames 1a and lb by hanging leads.

The island 2 is surrounded by an outer frame 1a connected to each other by tie bars 3.

The inner ends of a number of boards 4 supported by 1b are arranged. A wedge-shaped protrusion 6 having a constricted portion is provided on the side surface facing the island of the tie bar 3 between each lead, and the outer frame 1a.

A half-hole portion 5 having a constricted portion is provided on the inner side surface of 1b.

〔Effect of the invention〕

As described above, in the present invention, a semi-hole or protrusion having a constriction is provided on the side surface of the tie bar and outer frame facing the island, so that the side surface is formed on the surface of the sealing resin that contacts this side surface. Even if the plating layer is transferred and adhered,
A portion of this contact resin is removed when the tie bar and outer frame are cut and removed due to the half hole or constriction of the protrusion, so that the plating remaining on the resin portion 1o as shown in the perspective view of Fig. 3 is removed. Layer 11 is omitted at both ends between the leads, and there is no possibility of shorting between the leads.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is a plan view of a conventional lead frame in which a semiconductor element is fixed and sealed with resin, and FIG. 3 is a plan view for explaining the present invention in detail. FIG. la, lb, 7a, 7b...Outer frame, 2...
...Island, 3.13...Tie bar, 4.
・Gun・IJ-)”, 5.・Semicircular hole with a constriction, 6...Protrusion with a constriction, end...Semiconductor element, 9...・Ponding wire, 10・
... Sealing resin, 11... Plating layer. grass i yJ grass 2 凋l/3 grass 3 concave

Claims (1)

[Claims] An island to which a semiconductor element is fixed, a large number of leads arranged so that their inner ends are gathered around this island,
In the lead frame for a semiconductor device, which includes tie bars that connect a large number of leads to each other, and an outer frame that connects a large number of unit sections including the island and a large number of leads, the tie bar and the island of the outer frame are connected to each other. A lead frame for a semiconductor device, characterized in that it has a semi-hole portion or a protrusion portion having a constriction portion on a facing side surface portion.