Browse Prior Art Database

Reduction of Membrane Mask Distortion

IP.com Disclosure Number: IPCOM000122317D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 37K

Publishing Venue

IBM

Related People

Hoffman, S: AUTHOR [+3]

Abstract

Since a thin membrane mask used for electron or ion transmission pattern exposures has internal stress, non-uniform openings and non-uniform distributions of openings, distortion in the shape and position of the openings occurs. By adding otherwise unnecessary openings in the periphery of the membrane to create more uniform perforation across the membrane, the shape and relative position (registration) of desired patterns are more nearly as designed.

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Reduction of Membrane Mask Distortion

      Since a thin membrane mask used for electron or ion
transmission pattern exposures has internal stress, non-uniform
openings and non-uniform distributions of openings, distortion in the
shape and position of the openings occurs.  By adding otherwise
unnecessary openings in the periphery of the membrane to create more
uniform perforation across the membrane, the shape and relative
position (registration) of desired patterns are more nearly as
designed.

      Membrane materials having minimal internal stresses are used in
making transmission masks.  Improvement of pattern uniformity is
achieved by adding openings in the membrane where none are otherwise
necessary for device or circuit definition, e.g., outside of the
active region.  More uniform perforation within a mask and from mask
to mask therefore creates exposed regions having shapes and positions
more closely approximating design shapes and positions.

      Where it is necessary to use more than one patterned area in a
membrane for an exposure level, the pattern uniformity can be
optimzed and extra openings can be made around both patterned areas.

      Disclosed anonymously.