Chemistry Reference
In-Depth Information
oxidation The sensitivity of poly(furfuryl methacrylate) increases linearly when the concentration of
C
60
is increased from 5
10
3
mol/L. Saturation of sensitivity in the high C
60
concentration regions was observed to be due to deficiency of oxygen molecules in the resist films.
It was concluded that the dissolution rate of oxygen from the atmosphere into the resist film is lower
than its consumption rate [
164
].
Preparation of photocross-linkable furan-containing polyimides was also reported [
165
]. It was
also found that the polymer cross-links with the aid of singlet oxygen. Formations of fine pattern
images can be formed. This was taken as clear evidence of the successful photolithography in this
photo-curable system that uses C
60
as the photosensitizer [
165
].
10
5
to I
10.5.5 Polymers with Pendant Maleimide Groups
Preparation of photocross-linkable
co
- and terpolymers of
N
-isopropylacrylamide, 2-(dimethy-
lmaleimido)
N
-ethylacrylamide as the photosensitive component, and 3-acryloylaminopropionic acid
or
(2-(dimethylamino)ethyl)-acrylamide as ionizable comonomers was reported [
166
]. Here too,
cross-linking takes place through formation of cyclobutane moieties:
N-
y
y
x
x
O
O
O
O
UV light
NH
HN
NH
HN
2
O
O
O
O
N
N
N
O
O
O
O
HN
NH
x
y
10.5.6 Polymers with Pendant Abietate and Dibenzazepine Groups
Poly(vinylbenzyl abietate) in the film state is cross-linkable via photo-dimerization of the conjugated
carbon-carbon double bonds of the abietic acid moieties [
166
]. What the photo-dimerization product
looks like is not clear. Formation of a cyclobutane rings in photo-dimerization of steroids was
represented as follows [
166
]:
