Abstract: In the present study, protecting groups of moderatestability, such as acetals and ketals, wereinvestigated as pendant blocking groups in polyvinylphenols. Polymers were obtained by reacting enol etherswith the phenolic side groups to form acetal or ketalblocked phenols. Decomposition temperatures, glasstransition temperatures, and molecular weights of theresulting polymers were monitored and correlated withthe protecting group structure. Stability of theprotecting groups can be explained by protonationoccurring at either of the two oxygen sites, making twocleavage routes possible. Secondary reactions of thereleased protecting groups in the resist film wereinvestigated and discussed. The structure of theprotecting group was designed in order to meet basicresist properties such as resolution/linearity, DOF,post exposure delay latitude and thermal stability. ACanon FPA 4500 (NA $EQ 0.37) and a GCA XLS exposuretool (NA $EQ 0.53) were used for the optimizationprocess. A preoptimized resist formulation based on theabove criteria exhibits 0.23 $mu@m line/spaceresolution, 0.8 $mu@m focus latitude at 0.25 $mu@mresolution and approximately two hours post exposuredelay latitude. !25
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