Olefin, radiation-induced degradation

Infrared studies of the radiation-induced degradation of PMPS by Bowden et al. (19) supports the oligomerization process and also shows that the oligomers can be removed by post-exposure baking. These effects have not been seen for other poly (olefin sulfone)s (2.3). Figure 8 and Figure 9 show the yield versus dose curves for irradiation of poly(l-butene sulfone) and poly (cyclohexene sulfone) respectively (20). No comparable shift of the S02/olefin ratio towards unity is observed in the radiolysis of these polymers. 

Polysulfones have found use as resists in the area of mierolithography since the polysulfones are unstable toward radiation and heat below their melting points and the SO2 and olefin degradation products are volatile. It is interesting to note that some olefins undergo isomerization during the radiation induced degradation step [9c]. 

Poly(butene-l sulfone) (PBS), a sensitive, positive, electron beam resist, is highly sensitive to 185-nm radiation (Table 3.4) (9). However, PBS does not absorb above 200 nm, and the sensitization has not been successful. Incorporation of pendant aromatic rings into the polysulfone structure extends the photosensitivity to the DUV and mid-UV regions (72). Himics and Ross (73) reported that carbonyl-containing poly(olefin sulfones) such as poly(5-hexen-2-one sulfone) are sensitive to UV-induced degradation and... 

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