Browse Prior Art Database

Thermocompression Bonded MLC Components

IP.com Disclosure Number: IPCOM000109100D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Related People

Caulfield, T: AUTHOR [+7]

Abstract

With increased connections on ceramic carriers that serve as multichip carriers (MCMs) it will be necessary to use flex cables to provide interconnections. The packing densities are such that these flex connections will be stacked in a vertical direction to allow the great number of flexes to be attached to the substrate perimeter. Disclosed is a cable end to facilitate the multilayer flex attach process to the MCM using fired ceramic sheets with gold capped terminal via metallurgy.

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Thermocompression Bonded MLC Components

       With increased connections on ceramic carriers that serve
as multichip carriers (MCMs) it will be necessary to use flex cables
to provide interconnections.  The packing densities are such that
these flex connections will be stacked in a vertical direction to
allow the great number of flexes to be attached to the substrate
perimeter.  Disclosed is a cable end to facilitate the multilayer
flex attach process to the MCM using fired ceramic sheets with gold
capped terminal via metallurgy.

      The figure shows a cross-section of the cable end after
joining.  The ceramic layers are processed as a fired ceramic
carrier, each one having vias punched and filled with the appropriate
metal.  The terminals are then plated with Ni, diffusion bonded for
adhesion, plated with Cu followed by a 5-6 micron Au plate for
thermocompression joining.  The ceramic layers are loaded in a jig
that blind aligns the vias in each layer and the jig is subsequently
placed in the Gas Pressure Cell.  The cell is evacuated and
backfilled with nitrogen.  Pressure is applied to the copper bladder
of approximately 100 pounds per square inch while the temperature is
raised to 300 degrees C.  After a soak cycle of one hour the assembly
is returned to ambient temperature and vented.  While the cable end
in the figure illustrates three layers, it should not be considered a
limitation.