US 5,708,293 AGranted

Lead frame and method of mounting semiconductor chip

AssigneeMatsushita Electronics Corporation

InventorsTakao Ochi, Hisashi Funakoshi, Ichiro Okumura, Hajime Honma, Keiji Okuma, Keiichi Fujimoto

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Abstract

In a unit part of a lead frame for mounting a semiconductor chip, connecting leads and supporting leads extending from a lead frame main body toward a semiconductor chip mounting region are formed. Between each supporting lead and the lead frame main body, a movable part and a spring part for elastically supporting the movable part are disposed. The tip portion of the supporting lead connected with the movable part extends to the inside of the semiconductor chip mounting region in the natural state of the movable part, so that the tip portion butts against the side face of a semiconductor chip when the semiconductor chip is mounted. Thus, the semiconductor chip can be supported and fixed by using a bias force applied by the spring part. The base portions of the supporting leads, the movable part and the spring part do not remain in a package, and hence do not cause a stress in the package and do not increase the volume of the package. Thus, the invention provides a lead frame for forming a LOC package with high reliability which can contain a semiconductor chip having a large area within a regulated volume.

Claims16

Dependent claims

A lead frame for use in a resin sealed die-padless semiconductor package comprising:

a lead frame main body surrounding a semiconductor chip mounting region for mounting a semiconductor chip;
a plurality of connecting leads, each extending from said lead frame main body toward said semiconductor chip mounting region to be electrically connected with a part of said semiconductor chip;
a plurality of supporting leads each having a base portion connected with said lead frame main body and positioned out of a sealed area to be sealed by a resin, and a tip portion for clipping said semiconductor chip by butting against a side face of said semiconductor chip when said semiconductor chip is mounted;
a movable part disposed between at least one of said supporting leads and said lead frame main body relatively movably against said lead frame main body;
and
a spring part disposed between said movable part and said lead frame main body for elastically supporting said movable part and, when said movable part is shifted from a natural state thereof, for applying to said movable part a bias force in a direction reverse to movement of said movable part,
wherein said tip portion of said supporting lead connected with said movable part is positioned within said semiconductor chip mounting region in the natural state, is movable to be positioned out of said semiconductor chip mounting region in accordance with the movement of said movable part, and is adoptable to support said semiconductor chip by using the bias force of said spring part by butting against the side face of said semiconductor chip when said semiconductor chip is mounted.

4 more elements

A method of mounting a semiconductor chip comprising the steps of:

preparing a semiconductor chip;
preparing a lead frame including a plurality of connecting leads extending from a lead frame main body toward a semiconductor chip mounting region, a plurality of supporting leads each having a base portion connected with said lead frame main body and a tip portion extending toward said semiconductor chip mounting region, a movable part disposed between at least one of said supporting leads and said lead frame main body relatively movably against said lead frame main body, and a spring part disposed between said movable part and said lead frame main body for elastically supporting said movable part, and when said movable part is shifted from a natural state thereof, for applying to said movable part a bias force in a direction reverse to movement of said movable part;
positioning said tip portion of said supporting lead connected with said movable part out of said semiconductor chip mounting region by moving said movable part of said lead frame in a direction away from said semiconductor chip mounting region;
with said tip portion of said supporting lead connected with said movable part positioned out of said semiconductor chip mounting region, setting said semiconductor chip in said semiconductor chip mounting region to be disposed below said connecting leads, and aligning said semiconductor chip and said lead frame main body for setting a vertical distance between said connecting leads and a main face of said semiconductor chip within a predetermined range;
supporting said semiconductor chip by using the bias force of said spring part applied to said tip portion of said supporting lead by moving said supporting lead connected with said movable part in accordance with the bias force of said spring part until said tip portion of said supporting lead butts against a side face of said semiconductor chip;
with said semiconductor chip supported by said supporting lead, electrically connecting said connecting leads with a part of said semiconductor chip and conducting resin sealing;
and
cutting off a part of each of said supporting leads extending from a predetermined position between said tip portion and said base portion toward said lead frame main body, a part of each of said connecting leads closer to said lead frame main body, said movable part, said spring part and said lead frame main body to be separated from a sealed part.

5 more elements

Dependencies are inferred from the claim text.