Browse Prior Art Database

Local Passivation of Exposed Metal Areas by Decal Polymer Transfer

IP.com Disclosure Number: IPCOM000121194D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 51K

Publishing Venue

IBM

Related People

Caulfield, T: AUTHOR [+6]

Abstract

To make EC changes for current and future technologies it is necessary to add very fine metal lines under the active regions of the chips, both before and after chip joining. To prevent C4 solder interactions with these lines, a passivation of the metal areas will be needed. While nanodroplets of an appropriate polymer have been dispensed to cover the exposed metal, it has been found difficult to control such small volumes and place them accurately.

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Local Passivation of Exposed Metal Areas by Decal Polymer Transfer

      To make EC changes for current and future technologies it is
necessary to add very fine metal lines under the active regions of
the chips, both before and after chip joining. To prevent C4 solder
interactions with these lines, a passivation of the metal areas will
be needed.  While nanodroplets of an appropriate polymer have been
dispensed to cover the exposed metal, it has been found difficult to
control such small volumes and place them accurately.

      Proposed here is a technique using a passivating decal
structure supported on a suitable carrier film that when aligned over
the metal line is subjected to a controlled amount of heat and
pressure allowing transfer of this decal. Accurate areas of required
shapes can be fabricated on the carrier film using standard
photoprocessing and pattern transfer by plasma etching or RIE.  An
optional layer may be interposed between the carrier and the shapes
to facilitate the decal release from the carrier.  The controlled
pressure/temperature cycle can be generated using either a
resistively heated thermode with a diamond tip or a commercially
available TAB (Tape Automated Bonding) ILB (Inner Lead Bonding) tool
having a low pressure thermode control.  Successful transfer of
different polyimides has been effected using this technique.

      Disclosed anonymously.