JPH04290254A - Lead frame for semiconductor device - Google Patents

Abstract

PURPOSE:To increase the close contact property of a lead frame with a sealing resin while costs are reduced and to eliminate a need for an etching operation by a method wherein a plurality of holes are made in positions which are faced with inner leads near the edge end part of a semiconductor-element mounting stand part on which a semiconductor element is mounted and sealed with a resin. CONSTITUTION:A semiconductor-element mounting stand part 1 is formed along tips of inner leads 2; a plurality of through holes 3 are made at its end part. At this time, it is desirable that the gap between the semiconductor-element mounting stand part 1 and the tips of the inner leads 2 is narrow as far as possible. When a semiconductor device is assembled by using a lead frame having such a shape, wires which have wire-bonded electrodes on a semiconductor element to the inner leads 2 easily come into contact with the semiconductor- element mounting stand part 1. Therefore, it is desirable to paste an insulating tape 4 on the end part of the semiconductor-element mounting stand part 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame used in a semiconductor device, and more particularly to the shape of a semiconductor element mounting base thereof.

0002

[Prior Art] Conventionally, as shown in FIGS. 3 and 4, lead frames used for this type of semiconductor device have a semiconductor element mounting base 1 that is simply rectangular in shape, or a lead frame and a sealing resin. In order to improve the adhesion, a plurality of recesses (half-etch) 5 are formed on the inner leads 2 and the back surface of the semiconductor element mounting base 1 by etching. The position of this recess 5 is determined by the position of the internal lead in order to prevent problems such as breakage of the bonding wire due to the difference in thermal expansion between the lead frame and the sealing resin when the semiconductor device is mounted on a printed circuit board using the whole heating method. It needed to be near the bonding point.

0003

[Problems to be Solved by the Invention] In this conventional lead frame for semiconductor devices, in order to form the recesses 5 on the inner leads 2 and the back surface of the semiconductor element mounting base, etching processing is required, and pressing processing is not possible. However, it has been difficult to reduce costs even when the production volume is large. Further, when the recess 5 is formed in the internal lead 2, the strength of the internal lead is reduced, and there is a problem that the lead is easily deformed during the lead frame manufacturing process and the semiconductor device assembly process. Furthermore, as the number of pins in semiconductor devices has increased in recent years, and the internal leads have become thinner, there has been a problem in that it becomes difficult to process recesses.

[0004] The purpose of the present invention is to solve these problems and
It is an object of the present invention to provide a lead frame for a semiconductor device that improves the adhesion between the lead frame and a sealing resin while reducing costs, and eliminates the need for etching.

[0005]

[Means for Solving the Problems] The structure of the present invention provides a lead frame for a semiconductor device in which a semiconductor element is mounted on a semiconductor element mounting base part and then sealed with resin to assemble the semiconductor element, at the edge of the semiconductor element mounting part. A feature is that a plurality of through holes are formed near the end at a location facing the internal lead.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial plan view of a lead frame for a semiconductor device according to an embodiment of the present invention. FIG. 2 is a plan view of a lead frame for a semiconductor device according to a second embodiment of the present invention. The semiconductor element mounting base 1 of this embodiment is formed along the tip of the internal lead 2, and has a plurality of through holes 3 formed at the end thereof. At this time, it is desirable that the gap between the semiconductor element mounting base 1 and the tip of the internal lead 2 be as narrow as possible.

When a semiconductor device is assembled using a lead frame having such a shape, a wire such as a gold wire bonded between the electrode on the semiconductor element and the internal lead 2 comes into contact with the semiconductor element mounting base 1. There is a concern that this may happen. Therefore, in the second embodiment of the present invention shown in FIG. 2, an electrically insulating tape 4 is pasted to the end of the semiconductor element mounting base 1, or similarly an insulating liquid resin or the like is applied as thinly as possible. It is applied and cured.

According to the second embodiment, even if the bonding wire sag and comes into contact with the semiconductor element mounting portion 1 during the semiconductor device assembly process,
Electrical insulation can be maintained.

[0009]

As explained above, the present invention improves the adhesion between the sealing resin and the lead frame by providing a plurality of through holes in the vicinity of the edge of the semiconductor element mounting base. It has the same effect as a lead frame having a recess formed by processing. Further, the lead frame of the present invention can be manufactured by press working, and the production cost can be reduced to about 1/5 of the conventional one. Furthermore, since there is no need to form a recess on the internal lead, the strength of the internal lead is not reduced, and yields are improved during the lead frame manufacturing process and the semiconductor device assembly process.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view of an embodiment of the present invention.

FIG. 2 is a partial plan view of a second embodiment of the invention.

FIG. 3 is a partial plan view of a conventional lead frame for a semiconductor device.

FIG. 4 is a partial plan view of another example of a conventional lead frame.

[Explanation of symbols]

1 Semiconductor element mounting base 2 Internal lead 3 Through hole 4 Electrical insulation tape 5 Recess (half-etch)

Claims (1)

[Claims] 1. In a lead frame for a semiconductor device, which is assembled by placing a semiconductor element on a semiconductor element mounting base and sealing them with resin, a portion facing an internal lead near an edge of the semiconductor element mounting part; A lead frame for a semiconductor device, characterized in that a plurality of through holes are formed in the lead frame.