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Process for Fabrication of a Low Sputter Yield Reactive Ion Etching Mask

IP.com Disclosure Number: IPCOM000118410D
Original Publication Date: 1997-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Cordes, SA: AUTHOR

Abstract

Reactive Ion Etching (RIE) is a dry etch process which has a reactive or chemical component and a physical or sputter component. Typically, the process is controlled to enhance the chemical component, and the physical component is an undesirable aspect of the process, usually resulting in removal of the masking material used to pattern the RIE material. For processes where very deep etching of materials is required, this becomes a significant problem because the masking material must be very thick or it will be completely sputtered before the etch is complete.

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Process for Fabrication of a Low Sputter Yield Reactive Ion Etching
Mask

      Reactive Ion Etching (RIE) is a dry etch process which
has a reactive or chemical component and a physical or sputter
component.  Typically, the process is controlled to enhance the
chemical component, and the physical component is an undesirable
aspect of the process, usually resulting in removal of the masking
material used to pattern the RIE material.  For processes where very
deep etching of materials is required, this becomes a significant
problem because the masking material must be very thick or it will be
completely sputtered  before the etch is complete.

      The degree to which the mask is sputter etched is dependent on
the sputter yield of the material.  In order to minimize the
sputtering of the mask, a material with a low sputter yield such as
Al(2)O(3) is desirable.  The sputter yield of Al(2)O(3) is 0.02 atoms
per ion using argon ions with an energy of 600 volts.  This property,
along with  its low chemical solubility, makes it difficult to
pattern.  This disclosure describes a process by which an Al(2)O(3)
mask can be produced  easily and inexpensively using a standard
manufacturing tool set.

      One of the keys to this invention is having a sufficient amount
of aluminum, 3mum, to act as the anodization electrode.  An
insufficient thickness of aluminum will result in intermittent
anodization results.  Aluminum has proven to be the best material for
seve...