193 nm Resists for Deep Sub-Wavelength Applicatios.

Abstract

Among the chemistries/polymers reported for the 193nm photoresist applications, methacrylate copolymers consisting of 2-methyl-2-adamantane methacrylate (2-MadMA) and mevalonic lactone methacrylate (MLMA) and cycloolefin polymers derived from derivatives of norbornene have shown promising results. We have studied the lithographic properties of these two different promising chemistries. Both systems offer linear resolutions down to 130nm dense lines using conventional 193 nm illumination and high sensitivity at standard developer conditions. The etch rates of the methacrylate and cycloolefin based resists for polysilicon were found to be 1.4 and 1.3 times higher than that of novolak resist. Calculation of the normalized image log-slope (MILS) for both resist types shows that they can still resolve aerial images with a NILS of about 1.0, which is also confirmed by their 248nm performance. The potential of 193nm lithography is estimated at 110nm dense line resolution if resists can be improved to match the performance of dense line resolution if resists can be improved to match the performance of the best current 248nm resists which can resolve NILS values of about 0.7