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Photochemical Etching Process for Electronic Materials

IP.com Disclosure Number: IPCOM000101692D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Brannon, JH: AUTHOR [+3]

Abstract

A technique is described whereby electronically useful metals and dielectrics may be patterned without the need for wet lithographic processes or corrosive gases. The technique takes advantage of photochemical pathways available to certain molecules that create etchant species only where the patterned light goes.

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Photochemical Etching Process for Electronic Materials

       A technique is described whereby electronically useful
metals and dielectrics may be patterned without the need for wet
lithographic processes or corrosive gases.  The technique takes
advantage of photochemical pathways available to certain molecules
that create etchant species only where the patterned light goes.

      The figure shows the apparatus required to produce complete
patterns with this photochemical process. Collimated laser light 5
impinges upon a mask 7, producing an enlarged negative of the desired
pattern in light intensity.  A telecentric optical system 9 reduces
the light pattern and projects it through a chamber window 11,
focusing it onto the substrate surface 13.  The air is pumped out of
the chamber and a particular organic vapor or gas is introduced.
This organic gas is noncorrosive and does not affect the substrate 15
in any way.  But when irradiated by the laser 5, the gas-phase
molecules decompose into reactive etchants which then attack the
substrate surface 13.  Once a monolayer of the substrate has reacted
with the etchants, no further etching is possible unless more
substrate material is exposed to etchant.  The subsequent laser
pulses ablate the first layer of reaction products in addition to
creating more etchant in the gas phase.  Therefore, continued etching
occurs only in the areas that are illuminated, and a complete pattern
appears. Once etching has proceeded...