Browse Prior Art Database

Temperature Sensitive Internal Thermal Enhancement

IP.com Disclosure Number: IPCOM000113507D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Buller, ML: AUTHOR [+3]

Abstract

Disclosed is a thermal interconnection scheme which eliminates the continually loading the C4 interconnections in order to maintain sufficient contact for heat transfer purposes. The solution uses wires or cylinders made from interlaced shape memory alloy wire. The use of wires as an internal thermal enhancement has been shown to be beneficial both theoretically and experimentally and was patented by IBM in 1987. The novel approach established by the present disclosure is to use the properties of the recently developed shape memory alloy to provide the thermal enhancement without the continual force applied over the life of the package.

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This is the abbreviated version, containing approximately 62% of the total text.

Temperature Sensitive Internal Thermal Enhancement

      Disclosed is a thermal interconnection scheme which eliminates
the continually loading the C4 interconnections in order to maintain
sufficient contact for heat transfer purposes.  The solution uses
wires or cylinders made from interlaced shape memory alloy wire.  The
use of wires as an internal thermal enhancement has been shown to be
beneficial both theoretically and experimentally and was patented by
IBM in 1987.  The novel approach established by the present
disclosure is to use the properties of the recently developed shape
memory alloy to provide the thermal enhancement without the continual
force applied over the life of the package.

      A shape memory alloy is a metallic alloy which will change
shape within a prescribed temperature range dependent upon the
composition and processing of the alloy.  In the main embodiment of
this disclosure the cylinders or wire would be made, formed, and/or
processed such that at a given temperature the cylinder/wire would
increase in length sufficiently to contact both the back of the chip
and the package surface (Figure).

      In operation, the cylinder/wire would provide a path between
the chip and the heat sink.  When not in operation (sleep mode, power
off, etc.)  or when the machine was operating in a cool office
environment, the temperature would decrease sufficiently to reduce
the length of the cylinder/wire and remove the load force from the C4
in...