Browse Prior Art Database

Heat Spreader for Tape Ball Grid Array and Plastic Ball Grid Array Rework

IP.com Disclosure Number: IPCOM000112960D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Bielick, JD: AUTHOR [+4]

Abstract

Disclosed is a heat spreader device to decrease the thermal gradient across a module to aid in achieving the required temperature for rework without hot spots which might cause distortion or functional damage to the module.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 95% of the total text.

Heat Spreader for Tape Ball Grid Array and Plastic Ball Grid Array
Rework

      Disclosed is a heat spreader device to decrease the thermal
gradient across a module to aid in achieving the required temperature
for rework without hot spots which might cause distortion or
functional damage to the module.

      Tape Ball Grid Array (TBGA) and Plastic Ball Grid Array (PBGA)
packages do not heat up evenly which may make them difficult to
rework.

      Prior to the start of heat cycles, attach a heat spreader (A)
made of aluminum, copper or other appropriate material, i.e.,
ceramic, which spreads the heat evenly during the rework cycle.  The
heat spreader should be approximately the same length and width as
the component to be reworked.  It should be thick enough to approach
a zero temperature gradient over the area of the spreader during the
thermal cycle of rework.  Modules often have unprotected chip sites
in the middle which have maximum temperature limitations.  A cavity
(B) can be added to the heat spreader (A), above the chip and, if
necessary, an insulating material, i.e., polyimide, can be placed in
the cavity to thermally separate the heat spreader (A) and the chip.
This will decrease the maximum temperature the chip will see during
rework operation.  A thermal grease or flux can be placed between the
heat spreader and the component to be reworked to achieve better heat
transfer during the rework operation.  Ridges, bars or pins (C) are
used to achie...