Accurate critical dimension control by using an azide/novolak resist process for electron-beam lithography

Abstract

Nanofabrication with accurate critical dimension control was investigated with a nonchemically amplified resist. The resist consists of 3,3′-dimethoxy-4,4′-diazidobiphenyl and cresol novolak (novolak). By using novolak with a small weight-average molecular weight (Mw), small resist surface roughness (nano edge roughness) was significantly suppressed down to 3 nm. Nanofabrications of 20-nm lines and spaces (L and S) and 20-nm dot patterns had been demonstrated with the resist. The pattern line-width linearity, the minimum size that the fabricated patterns width were equal to the designed ones, was also preserved down to 30-nm L and S. We investigated use of electron-beam/optical lithography to enhance throughput in nanofabrication. Fine gate structure of 70 nm with a large pad was demonstrated with the hybrid exposure.