Browse Prior Art Database

Recessed Ceramic Via Protection

IP.com Disclosure Number: IPCOM000120943D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 39K

Publishing Venue

IBM

Related People

Agostino, PA: AUTHOR [+2]

Abstract

This is to disclose a method of protecting a recessed via of a ceramic substrate during a polymer backfill process for filling surface voids within that substrate.

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Recessed Ceramic Via Protection

      This is to disclose a method of protecting a recessed via of a
ceramic substrate during a polymer backfill process for filling
surface voids within that substrate.

      A low viscosity, soluble polymer, such as probimide 285 or
probimide 286 (Trademarks of Ciba Giegy Corporation) is applied to
the surface of a substrate to form up to a 3 micron thick uniform
film.  The ceramic substrate is then baked prior to the application
of a second polymer in the void backfill process.  The soluble
polymer film covers the recessed via while only filling a small
volume of the ceramic voids.  The normal polymer backfill material is
applied to form a much thicker uniform film, which then fills the
remainder of the void, mixing with the probimide material.  The
ceramic substrate is heated to a temperature high enough to cure the
backfill, yet low enough not to cross link the probimide material.
The ceramic substrate is subsequently polished to remove the polymer
films on the top surface of the substrate.  The soluble polymer,
covered by the backfill polymer, is protected and remains in the
voids. The probimide covering the recessed via is removed by
dissolution in a solvent bath.  Thus, the recessed via is uncovered
while the voids remain filled.

      Disclosed anonymously.