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Semi-Aqueous Solution for Stripping Solvent Resist Riston T168

IP.com Disclosure Number: IPCOM000112425D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Bantu, NR: AUTHOR [+2]

Abstract

Disclosed is the new alternate semi-aqueous solution for stripping the negative photoresist, Riston T168*.

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Semi-Aqueous Solution for Stripping Solvent Resist Riston T168

      Disclosed is the new alternate semi-aqueous solution for
stripping the negative photoresist, Riston T168*.

      Negative photoresists, being cross-linked enough to survive in
harsh conditions in the processes, become difficult to strip from the
substrate and require polar solvents such as methylenechloride.
Because of growing concerns, related to toxicity and environment, the
chlorinated solvents have been focused to eliminate from the
industrial processes.  Alternatively, a mixture of formic acid (88%)
and water (12%) (v/v) semi-aqueous solution, has been found to strip
the cross-linked resist even at room temperature.

      The stripping rate has gradually increased by increase in
temperature.  The stripping time is 6 min.  at room temperature
(20ºC) while 3 minutes at 40ºC.  With spray pressure
and brushing action, the stripping time can be reduced considerably.

      The stripping mechanism of formic acid solvent can be
attributed to its polar nature and hydrogen bonding capacity.  Formic
acid acts as a proton donor using its acidic proton while the
carbonyl groups on the binding polymer act as a proton acceptor [*].

*  Trademark of E. I. du Pont de Nemours & Co.

Reference

[*]  J. A. Brydson, "Plastic Materials," Butterworth Scientific
   Boston, USA., 79 (1982).