Performance of 193-nm resists based on alicyclic methacrylate and cyclo-olefin systems

Among the chemistries/polymers reported for the 193nm photoresist applications, methacrylate copolymers consisting of 2-methyl-2-adamantane methacrylate and mevalonic lactone methacrylate and cycloolefin polymers derived from derivatives of norbornene have shown promising results. We have studied the lithographic properties of these two but different promising chemistries. Both system offer linear resolutions down to 0.13 micrometers using conventional 193 nm illumination and high sensitivity at standard developer conditions. While the methacrylate based system shows best performance on substrates with bottom coats, the cycloolefin-Maleic anhydride alternate copolymer based resists performs well on bare silicon as well as substrates with bottom coats. The etch rates of the methacrylate and cycloolefin based resists were found to be 1.4 and 1.3 times relative to that of KrF resist APEX-E. Further, new polymers consisting of isobornyl and alkyl ether chains on the ester groups of norbornene carboxylate were made in order to decrease the glass-transition temperatures of the norbornene-maleic anhydride type polymers. These results will be included and discussed in detail.