Browse Prior Art Database

High Performance Die-to-Heat Sink Interface for Conduction and Immersion Cooling of Electronics

IP.com Disclosure Number: IPCOM000105511D
Original Publication Date: 1993-Aug-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Chu, RC: AUTHOR [+2]

Abstract

Resistance to heat flow across the die-to-heat sink interface is a major contributor to the overall thermal resistance in both conduction and liquid immersion cooling schemes for electronics. Placing materials with a high thermal conductivity at the interface, including oils and oil-particle pastes, is known to reduce the interface resistance. Liquid metals offer much higher thermal conductivities as interface fill compounds, but are generally unsuitable because they do not adequately wet the silicon die.

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High Performance Die-to-Heat Sink Interface for Conduction and Immersion Cooling of Electronics

      Resistance to heat flow across the die-to-heat sink interface
is a major contributor to the overall thermal resistance in both
conduction and liquid immersion cooling schemes for electronics.
Placing materials with a high thermal conductivity at the interface,
including oils and oil-particle pastes, is known to reduce the
interface resistance.  Liquid metals offer much higher thermal
conductivities as interface fill compounds, but are generally
unsuitable because they do not adequately wet the silicon die.

      Disclosed is a thin, composite layer of reflowable metal and
wax that is applied to the surface of the heat sink that faces the
die.  The metal is deposited using vapor deposition, electro-chemical
plating or other conventional means.  A wax is then applied over the
metal layer so that the wax will first contact the back of the die.
Heat sinks are installed in an assembled module with an appropriate
loading force against the die.  When the module is fully assembled, a
reflow operation is performed in which the wax and metal flow to
conform to the die curvature and to other die and-or heat sink
interface flaws.  The wax serves as a lubricant and wetting agent as
the metal is displaced.  Since the thermal conductivity of the
wax-metal composite is much higher than that of oil, paste and other
conventional interface fillers, the resistance to heat flow a...