Browse Prior Art Database

Pin Attach/Chip Join Fixture

IP.com Disclosure Number: IPCOM000112354D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Moore, SP: AUTHOR [+2]

Abstract

Disclosed is a fixture which allows the chip and pins to be joined simultaneously to a metallized ceramic substrate. Joining the pins and chip in the same process reduces unit hour costs, chemical use, and the potential for pin movement during chip join.

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Pin Attach/Chip Join Fixture

      Disclosed is a fixture which allows the chip and pins to be
joined simultaneously to a metallized ceramic substrate.  Joining the
pins and chip in the same process reduces unit hour costs, chemical
use, and the potential for pin movement during chip join.

      The fixture (Fig. 1) contains pin guide holes corresponding to
the desired pin pattern.  Headed pins are loaded into the fixture and
thed substrate, prepared by screening 10/90 solder paste on the thin
film Cu pin pads, is mated to the pin array (Fig. 2).  This assembly
is then inverted and placed on a flat plate (Fig. 3).  The chip is
placed through a cavity in the center of the fixture and the assembly
is run through a standard atmosphere furnace where the C4s and
screened solder is reflowed.

      The fixture is designed so there is a gap between the pin head
and fixture when the assembly is inverted (Fig. 3).  This allows
vertical pin movement to compensate for ceramic camber.  The ceramic
is located relative to the pin guide holes by the corners of the
fixture so the pin interface.  Heads are in line with the solder pads
on the substrate.

      Graphite is a proposed fixture material because it is not
wettable by solder, has the same thermal expansion coefficient as the
ceramic head substrate material currently qualified and is easily
machineable.  Other fixture materials may be better suited for use
with other substrate materials.