A soluble multiblock copolyimide without specific functional groups such as
OH and COOH was prepared by a direct one-pot polycondensation of two types
of dianhydrides and diamines in the presence of gamma -valerolactone/pyrid
ine catalyst using N-methylpyrrolidone (NMP)/toluene mixture as a solvent.
The polyimide film containing the photosensitive agent diazonaphthoquinone
(DNQ) compound gave positive-tone behavior by UV irradiation, followed by d
evelopment in a mixture of ethanolamine/NMP/H2O (1/1/1 by weight). The scan
ning electron microscopic photograph of the resultant image showed fine pat
terns with about 20 mum film thickness. Its pattern forming was based on th
e photorearrangement of diazonaphthoquinone, a process in which the ring-op
ening reaction of imide units of the polyimide with the amine used as a dev
eloper and the following degradation of the polymer are induced. Such a new
imaging technique combines principles of photolithography and etching of a
polyimide to give, what we call, reaction development patterning in which
the main chemical reactions directly related to the pattern formation occur
during development. (C) 2001 John Wiley & Sons, Inc.