Browse Prior Art Database

Improved and Cost-Reduced Interposer for Higher-Risk Processes

IP.com Disclosure Number: IPCOM000111109D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Baumberger, JG: AUTHOR [+4]

Abstract

Disclosed is an interposer whose primary purpose is to act as a carrier for higher-risk processes such as special platings (gold, etc.) on the contact pads that might limit or impact the yields of printed circuit structures (such as boards, cards, or modules), while still allowing large enough contact pads for adequate alignment tolerances and the proper functioning of high-density area array interconnections. Therefore if, for example, a gold-plated contact pad on a board goes bad in the field, the board must still be returned to the factory to be reworked. But if the particular contact pad can't be worked, it may be preferable and less expensive to replace the interposer instead of scrapping the board.

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This is the abbreviated version, containing approximately 59% of the total text.

Improved and Cost-Reduced Interposer for Higher-Risk Processes

      Disclosed is an interposer whose primary purpose is to act as a
carrier for higher-risk processes such as special platings (gold,
etc.) on the contact pads that might limit or impact the yields of
printed circuit structures (such as boards, cards, or modules), while
still allowing large enough contact pads for adequate alignment
tolerances and the proper functioning of high-density area array
interconnections.  Therefore if, for example, a gold-plated contact
pad on a board goes bad in the field, the board must still be
returned to the factory to be reworked.  But if the particular
contact pad can't be worked, it may be preferable and less expensive
to replace the interposer instead of scrapping the board.

      Fig. 1, a top view of the interposer, shows a dielectric layer
and a series of contact pads.  Fig. 2, a bottom see-through view of
the interposer, shows the dielectric layer, the series of contact
pads, and the holes used to form vias for respective contact pads.
Fig. 3, which is a cross-sectional view of the interposer as part of
a typical application, shows the conductive attachment of the
interposer to a printed circuit structure.

      The interposer (Fig. 1) has one layer of circuitry preferably
built on a layer of dielectric material such as Kapton* or Upilex**.
The circuitry consists of a series of pads that may be used to
contact the interposer to an area array interconnect...