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Dendritic Circuit Reroute Applique

IP.com Disclosure Number: IPCOM000115450D
Original Publication Date: 1995-May-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Beers, GE: AUTHOR [+3]

Abstract

In the testing of complex circuit carriers, it is frequently helpful to "jumper" or bypass some connections for the testing of certain functions. For circuit carriers which use Direct Chip Attach (DCA), Ball Grid Array (BGA) or Solder Column Array (SCA) footprints, spacing of interconnects on the circuit carrier is small and use of a physical wire is difficult. This is compounded when there are numerous connections which are to be made.

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Dendritic Circuit Reroute Applique

      In the testing of complex circuit carriers, it is frequently
helpful to "jumper" or bypass some connections for the testing of
certain functions.  For circuit carriers which use Direct Chip Attach
(DCA), Ball Grid Array (BGA) or Solder Column Array (SCA) footprints,
spacing of interconnects on the circuit carrier is small and use of a
physical wire is difficult.  This is compounded when there are
numerous connections which are to be made.

      The testing and circuit rerouting issue has been dealt withby
producing a circuit carrier, termed a circuit reroute applique or
bypass module, which interfaces with a dendritic interposer as shown
in Figs. 1 and 2.  The dendritic interposer module (*) facts as a
socket for array attachment devices on a circuit card.  The applique
provides the means to connect predetermined dendrite pads on the
interposer using copper circuit traces and compliant metal pads.

      The electrical characteristics of the applique are designed to
be consistent with the planar and module designs.  The physical
layout as shown is planar, meaning that no circuit traces need to
cross others, allowing a single-sided design.  It would be possible
to provide a ground plane on the opposite surface of the circuit
board for controlled impedance transmission line designs.  Here full
speed operation would be possible.  Similarly, this applique could be
composed of several wiring layers connected by vias (a conventional
printed wiring board) so th...