Browse Prior Art Database

Plastic Package Cooling Method

IP.com Disclosure Number: IPCOM000061131D
Original Publication Date: 1986-May-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Phelps, DW: AUTHOR [+2]

Abstract

By molding a cavity in a plastic chip package and thus providing access to the back of a semiconductor chip, a finned metal heat sink is mounted in good thermal contact with the back of the semiconductor chip. This technique permits use of an inexpensive plastic package while not limiting its use to chips requiring less than 1/2 watt of heat dissipation.

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Plastic Package Cooling Method

By molding a cavity in a plastic chip package and thus providing access to the back of a semiconductor chip, a finned metal heat sink is mounted in good thermal contact with the back of the semiconductor chip. This technique permits use of an inexpensive plastic package while not limiting its use to chips requiring less than 1/2 watt of heat dissipation.

Referring to the figure, a semiconductor chip 2 is wire bonded to leads and back bonded to a portion of the lead frame assembly 4. This portion of the assembly 4 is usually a square of copper about the size of the chip 2. The plastic package 6 is then molded providing an opening to the back of the chip as shown. Following a standard deflashing operation to remove any thin layer of plastic which might be formed at the bottom of the cavity during molding, the finned heat sink 8 is bonded to the plastic 6 and to the exposed portion of the lead frame assembly 4 by means of a conductive epoxy 10.

Disclosed anonymously.

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