Browse Prior Art Database

Chip Cooling

IP.com Disclosure Number: IPCOM000089745D
Original Publication Date: 1977-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Krumm, H: AUTHOR

Abstract

Means are described which allow a combination of the advantages obtainable by soldering chips to a substrate by flip-chip technology (high degree of reliability of the bond, simple contacting) with those offered by back-bond technology (effective cooling), without neglecting differences in chip height invariably encountered in multichip arrangements.

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Chip Cooling

Means are described which allow a combination of the advantages obtainable by soldering chips to a substrate by flip-chip technology (high degree of reliability of the bond, simple contacting) with those offered by back-bond technology (effective cooling), without neglecting differences in chip height invariably encountered in multichip arrangements.

The figures show chips 2 soldered to a ceramic carrier 1 by conventional methods. The thermal resistance of the chip/substrate connection, which is determined by the pads, is essentially higher than that of back-bonded chips which are pressed (glued, soldered) onto the substrate. In the structure described, good thermal contact is obtained, while maintaining the solder pads on the active chip side for electrical connection.

To this end, module cap 3 is mechanically connected to substrate 1. As illustrated by junctions 4, a ceramic cap could be connected by epoxy and a metal cap by soldering. To that extent the arrangement is orthodox.

In multichip arrangements of this kind the space between the inner face in the recesses of cap 3 and the back side of chips 2 generally differs from chip to chip because of differences in chip thicknesses, pad heights, substrate unevenness, etc. Neglecting these facts may impair the heat transfer as well as the mechanical and electrical reliability. As shown in enlarged section in Fig. 2, this space can be filled with heat transfer material 5 to enhance the cooling of chips...