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Hexamethyldisilazane Lift-Off Process

IP.com Disclosure Number: IPCOM000113990D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Pfeiffer, AT: AUTHOR [+2]

Abstract

The present hexamethyldisilazane (HMDS) lift-off process allows for short exposure time and variation in the thickness of the overhangs. An additional advantage of the HDMS lift-off process is that it allows the photoresist to be stored for long periods of time before exposure. After treatment in accordance with the present process the resist is exposed through a mask and developed by conventional techniques. The present HMDS lift-off process uses two components: a positive photoresist such as AZ, HC, or a Shipley 1350 J modified by Alnoval 320K phenol formaldehyde resin; and hexamethyldisilazane (HMDS). The HMDS lift-off process is safe and complies with government restrictions in countries such as West Germany and the United Kingdom.

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This is the abbreviated version, containing approximately 60% of the total text.

Hexamethyldisilazane Lift-Off Process

      The present hexamethyldisilazane (HMDS) lift-off process allows
for short exposure time and variation in the thickness of the
overhangs.  An additional advantage of the HDMS lift-off process is
that it allows the photoresist to be stored for long periods of time
before exposure.  After treatment in accordance with the present
process the resist is exposed through a mask and developed by
conventional techniques.  The present HMDS lift-off process uses two
components: a positive photoresist such as AZ, HC, or a Shipley 1350
J modified by Alnoval 320K phenol formaldehyde resin; and
hexamethyldisilazane (HMDS).  The HMDS lift-off process is safe and
complies with government restrictions in countries such as West
Germany and the United Kingdom.

      The Figures illustrate three types of overhangs which can be
produced by the present HMDS process.

      In Fig. 1, a thin wide overhang 2 can be formed on resist 4 by
flooding the top surface of the resist layer 4 with HMDS.  The HMDS
reacts with the top few thousand angstroms of the resist in a
self-terminating reaction taking less than 60 seconds.  The HMDS
reaction forms a thin protective coating.  After the HMDS reaction is
complete, excess HMDS is removed (spun off) and the substrate is
baked at between about 70ºC and 75ºC.   The resist is exposed
through a mask and developed in the conventional manner of developing
photoresist.

      The unexposed HMDS-...