Browse Prior Art Database

Fabrication of Grooved Glass Substrates by Phase Mask Lithography

IP.com Disclosure Number: IPCOM000119457D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Related People

Brock, PJ: AUTHOR [+4]

Abstract

Disclosed is a lithographic mask structure which does not contain opaque metal elements and does not require the deposition of a phase shift element. This mask does not have any opaque chrome elements but consists of a fused quartz substrate with a relief pattern etched into the surface of the quartz. A phase-shifting mask can be used to print servo groove patterns for optical storage disks and provides improved contrast and resolution in printed photoresist images when used in a suitable projection printer.

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Fabrication of Grooved Glass Substrates by Phase Mask Lithography

      Disclosed is a lithographic mask structure which does not
contain opaque metal elements and does not require the deposition of
a phase shift element.  This mask does not have any opaque chrome
elements but consists of a fused quartz substrate with a relief
pattern etched into the surface of the quartz.  A phase-shifting mask
can be used to print servo groove patterns for optical storage disks
and provides improved contrast and resolution in printed photoresist
images when used in a suitable projection printer.

      Such a photomask structure can be fabricated in the following
way.  Onto a conventional photoresist coated chrome on fused quartz
photomask blank is written a pattern of concentric lines and spaces
or a spiral pattern.  The photoresist is developed and the exposed
chrome etched in the usual way to yield a transmission mask pattern
of twice the pitch desired in the final groove pattern.  The quartz
is then etched, using the photoresist/chrome pattern as the resist,
by either a wet or dry process, to a uniform depth. The depth of
quartz etch must be controlled as well as the width of the groove and
land in the mask as well as the radius at the bottom of the etched
groove walls.  Phase shifting masks can be fabricated to successfully
print photoresist images on glass disks to yield grooved glass
structures of 1.5 mm pitch, 1.2 mm pitch, and 1.0 mm pitch. The
resulting photoresist...