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MLR Structure Using Silicon Polyimide Support Layer With Low Tg Polyorganosiloxane Resists

IP.com Disclosure Number: IPCOM000102537D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Kwong, R: AUTHOR [+4]

Abstract

Disclosed is an MLR method that extends the utility of polydimethylsiloxanes (PDMS) and related low Tg resist materials to form lift-off structures. The method involves interposing a thin layer of a high Tg (>100oC) siloxane polyimide (SiPI) between the PDMS resist layer and the planarizing dielectric, soluble polyimide or hard baked AZ type underlayer. After lithographic patterning of the resist layer, the image is transferred into the silicon polyimide intermediate layer by CF4/O2 RIE followed by O2 RIE to replicate pattern into the underlayer.

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MLR Structure Using Silicon Polyimide Support Layer With Low Tg Polyorganosiloxane Resists

       Disclosed is an MLR method that extends the utility of
polydimethylsiloxanes (PDMS) and related low Tg resist materials to
form lift-off structures.  The method involves interposing a thin
layer of a high Tg (>100oC) siloxane polyimide (SiPI) between the
PDMS resist layer and the planarizing dielectric, soluble polyimide
or hard baked AZ type underlayer.  After lithographic patterning of
the resist layer, the image is transferred into the silicon polyimide
intermediate layer by CF4/O2 RIE followed by O2 RIE to replicate
pattern into the underlayer.

      The PDMS based resists are known to have high sensitivity to E-
beam but due to rather low Tg and consequent problem of image
distortion during dry etching, application of these materials is
limited to mask fabrication and other processes not requiring
overhang or lift-off profile.  According to the present method,
incorporation of SiPI layer prevents the flow of PDMS image during
RIE and overetch of the underlayer to create an overhang.  The RIE'd
pattern profile is maintained during high temperature sputter clean
and metal deposition conditions.

      Typical siloxane polyimides found useful according to this
method are product of condensation reaction of benzophenone
tetracarboxylic dianhydride (BTDA) or pyromellitic dianhydride
(PMDA), aromatic diamine (4,4'-oxydianiline, 4,4'methylene dianiline
etc.), and bis-...