Browse Prior Art Database

Semiconductor Chip Cooling Package

IP.com Disclosure Number: IPCOM000089085D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Doo, VY: AUTHOR [+2]

Abstract

Shown is a semiconductor package with enhanced cooling. In the package, a flanged semiconductor circuit chip is bonded by a process, such as eutectic (gold-silicon) alloying or conductive epoxy, onto a thermoconductive substrate, such as silicon, molybdenum, invar, and the like, with the unit referred to as a "piggy-back wafer".

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Semiconductor Chip Cooling Package

Shown is a semiconductor package with enhanced cooling. In the package, a flanged semiconductor circuit chip is bonded by a process, such as eutectic (gold-silicon) alloying or conductive epoxy, onto a thermoconductive substrate, such as silicon, molybdenum, invar, and the like, with the unit referred to as a "piggy-back wafer".

The piggy-back wafer is flip-chip bonded by solder joints onto the pads of the metallization on the module substrate, with the flange of the piggy-back wafer resting on a square donut-shaped ground plane which physically supports the wafer when pressure is applied to the top surface thereof. The ground plane has a square opening complementary to the chip for insertion therein, to allow the chip to be bonded to the module substrate, as shown in the drawing. The ground plane is supported in position by suitable insulating spacers.

Even though a ground plane may not be required in the module structure for electrical integrity, it is incorporated in the unit for physical integrity to support and level the piggy-back chip, via softened solder joints, as it is bonded to the module substrate. It is comprehended that the square donut-shaped plate has a thermal expansion coefficient which matches that of the piggy-back wafer unit, as, for example, molybdenum, invar, glass ceramic, and the like. The composition of the module substrate is selected for the same thermal expansion matching, and can be formulated of gl...