OAI and PSM used in 193-nm microlithography

摘要

Abstract: OAI and PSM which are effective to improve the resolution and DOF are new accepted as key technologies by extending the limit of optical lithography. However, for these techniques, it is very difficult to control the pattern size error within 10 percent as the pattern size becomes smaller. The physical mechanisms of resolution and DOF enhancement of the new annular illumination and the new mask is briefly discussed. Some result of simulation to investigate the basic lithographic characteristics of the new annular illumination and the new mask are presented. The structure of the mask is presented in this paper. Finally, experiments have been carried out to verify the characteristic of the new annular illumination and the new mask, and the results verified the enhancement of lithographic performance. In i- line exposure system, we obtained best resolution of 0.35 micron and 2.4 micron DOF for 0.6 micron feature size. In our simulation, with 193 nm exposure wavelength, 0.13 micron pattern size can realized with 2.0 micron DOF, and the proximity effect decreased obviously. !7