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Browse Prior Art Database

Alignment Mark Exposure Method for X-Ray Lithography Systems

IP.com Disclosure Number: IPCOM000102232D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Schmidt, DA: AUTHOR

Abstract

By adding visible light exposure of alignment marks built into each X-ray mask external to its X-ray exposure field, accurate level-to- level alignment of images formed by X-ray exposures is achieved. Appropriate photoresist exposure illumination may have to be added to an X-ray exposure system. This usually can be accomplished within viewing optics already incorporated in standard systems for mask-to- wafer alignment. Using the technique described, the area of X-ray exposure need not be altered for reasons of alignment aid placement.

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Alignment Mark Exposure Method for X-Ray Lithography Systems

       By adding visible light exposure of alignment marks built
into each X-ray mask external to its X-ray exposure field, accurate
level-to- level alignment of images formed by X-ray exposures is
achieved.  Appropriate photoresist exposure illumination may have to
be added to an X-ray exposure system.  This usually can be
accomplished within viewing optics already incorporated in standard
systems for mask-to- wafer alignment.  Using the technique described,
the area of X-ray exposure need not be altered for reasons of
alignment aid placement.

      The figure is a plan view of one embodiment of an X-ray mask
comprised of mounting framework 10 within which regions 12 may be
used to incorporate alignment aids, e.g., aids 14, to be exposed by
visible radiation to create an image in photoresist on a substrate.
Images 16 are used to align to images on the substrate created by a
previous exposure. Region 18 is the X-ray exposure area containing
circuit and device images.  Region 18 is optimized for X-ray mask
construction without regard to visible light transmission while
regions 12 are optimized for visible light viewing and exposure.

      Depending on alignment detection methods and photoresist used,
it may be necessary or advantageous to provide one wavelength of
visible light for alignment and another for exposure of photoresist
to new alignment mark images.  This is accomplished in one standa...