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Browse Prior Art Database

Dendrite Connectors for Low Temperature System Packaging

IP.com Disclosure Number: IPCOM000102764D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 57K

Publishing Venue

IBM

Related People

Almquist, FA: AUTHOR

Abstract

Computing systems proposed for operation at cryogenic temperatures require a single carrier for the logic chip package. As a result, a large number of interconnections are required to support the signals, shields, and power requirements. This requirement dictates small contacts on tight spaces. Since the carrier is small, and the contact count numbers between 1,500 and 2,000, a high-density disconnectable connection system is required. Dendrite contacts on a flexible film will meet the interconnection requirements.

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Dendrite Connectors for Low Temperature System Packaging

      Computing systems proposed for operation at cryogenic
temperatures require a single carrier for the logic chip package.  As
a result, a large number of interconnections are required to support
the signals, shields, and power requirements.  This requirement
dictates small contacts on tight spaces.  Since the carrier is small,
and the contact count numbers between 1,500 and 2,000, a high-density
disconnectable connection system is required.  Dendrite contacts on a
flexible film will meet the interconnection requirements.

      For dendritic connectors, a specially controlled, high current
plating is used to "grow" a multitude of needle-like projections on
the contact areas.  All mating contact surfaces on the carrier and
the flexible I/O cable are plated with dendrites.  Electroplating is
a batch fabrication process where dendrites are grown on all contact
faces simultaneously.

      A multilayer polymide/copper film is circuitized with signal
lines and power planes then patterned to provide multiple rows of
contacts on centers as tight as 0.01 inch. Dendrites are plated on
contact pads that are typically .005 inch diameter and pressure
connected to a similar dendrite pattern plated on the perimeter of
the chip carrier.  A mechanical clamping pressure is applied to
ensure contact integrity.  To maintain uniform pressure, a knit wire
mesh is used between the flex cable and the loading bar.  F...