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Heat Transfer Structure for Semirigidly Mounted, Solder Ball-Connected, IC Chip

IP.com Disclosure Number: IPCOM000099898D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Snyder, KA: AUTHOR [+2]

Abstract

Disclosed is a physical structure for the removal of heat from an integrated circuit (IC) chip that is mounted by solder ball connections to a multilayer printed circuit (MPC) board.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 62% of the total text.

Heat Transfer Structure for Semirigidly Mounted, Solder Ball-Connected, IC Chip

       Disclosed is a physical structure for the removal of heat
from an integrated circuit (IC) chip that is mounted by solder ball
connections to a multilayer printed circuit (MPC) board.

      Advantage is taken of the fact that the back or non-functional
side of IC chips is usually flat within a few micrometers and that an
oil film only a few micrometers in thickness is only a slight barrier
to heat flow.  Adding to these a careful design and selection of
materials, the structure shown in the figure is produced which offers
superior thermal performance to what is available by the use of
thermal grease, for example.

      Referring to the figure, the structure consists of the MPC
board 1 with IC chip 2 mounted by means of a multitude of solder
balls 3.  Laminated to board 1 by a thin adhesive layer is a metal
plate 4 having a thermal expansion coefficient about equal to that of
MPC board 1.  Metal plate 4 has a preformed square, or other shaped
holes, centrally located at each chip site on the board.  A heat sink
assembly 5 is positioned and perimeter-bonded in each opening in the
plate.  The heat sink assembly 5 is made of two parts: a base plate 6
and a corrugated fin 7.  These two parts are joined by any fusion
process that results in a very low resistance to heat transfer.  Base
plate 6 should be made of the same material as plate 4, and in the
example shown a lamina...