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Control of Silicon Micromachining

IP.com Disclosure Number: IPCOM000115160D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 62K

Publishing Venue

IBM

Related People

Austin, LW: AUTHOR [+2]

Abstract

A method is described for using oxidative catalysts to vary silicon etch selectivity by controlling anisotropic etch rates. Both the concentration and nature of oxidative catalysts used in wet chemical etching can be used to alter the etch rates of the three major crystal faces of silicon. By the proper choice of catalyst and its concentration, etch rates of a desired crystalline plane can be retarded or accelerated for the purpose of micromachining silicon.

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Control of Silicon Micromachining

      A method is described for using oxidative catalysts to vary
silicon etch selectivity by controlling anisotropic etch rates.  Both
the concentration and nature of oxidative catalysts used in wet
chemical etching can be used to alter the etch rates of the three
major crystal faces of silicon.  By the proper choice of catalyst and
its concentration, etch rates of a desired crystalline plane can be
retarded or accelerated for the purpose of micromachining silicon.

      Oxidative catalysts can be used to control anisotropic etch
rates by adding them to the following general etchant:
  o  3650 ml ethanolamine
  o  1660 ml water
  o  1150 g  gallic acid complexing agent
         3 ml 10% FC-129* surfactant to eliminate channeling

      With no catalysts, the general etchant has relative etch rates
of 36:40:19 for the 100,110,111 planes.  The etch rates are altered
as shown in the Table for a variety of added catalysts.
  **  Trademark of 3M, Commercial Chemical Division