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Browse Prior Art Database

Copper Passivation During Etch-stop Patterning

IP.com Disclosure Number: IPCOM000109950D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Related People

Cataldo, JK: AUTHOR [+5]

Abstract

A process is disclosed which simplifies the fabrication of multilayer circuitry where etch-stop is used to maintain planarity.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 82% of the total text.

Copper Passivation During Etch-stop Patterning

      A process is disclosed which simplifies the fabrication of
multilayer circuitry where etch-stop is used to maintain planarity.

      In packaging technology, common fabrication processes for
multilayer circuitry use RIE (reactive ion etching) or laser
processes to pattern polyimide.  The patterned polymer is then filled
with copper and the excess copper is removed by planarization
techniques.  This process leaves exposed copper which must then be
passivated (typically with chrome) to enhance adhesion to the next
layer of polyimide.

      Copper passivation can be done by a sub-etch process or by a
lift-off process where thin chrome is evaporated over patterned
resist.  At process levels where etch-stop is used and copper
passivation is practiced, three lithography steps are required:  one
step to pattern the polymer, one step to passivate the copper and one
step to pattern the etch-stop.

      One of these three lithography steps can be eliminated by
performing a chrome evaporation AFTER the etch-stop has been
patterned.  A summary of the process is as follows:
      1.   Etch-stop is coated over the patterned copper/polyimide.
      2.   Resist is coated over the etch-stop and exposed, repeating
the pattern below the etch-stop.
      3.   The etch-stop is patterned using standard patterntransfer
techniques.
      4.   Blanket chrome is evaporated over the patterned etch...