Sub 100nm DRAM cell patterning results and relation with lens aberration at 248nm lithography era

摘要

248nm wave lithography process is being pushed and extended to sub 130nm node by continuous RET(Resolution Enhancement Technique) improvement. By applying various kind of RET such as exposure lens NA(Numerical Aperture) enlargement, more strong OAI(Off Axis Illumination), elaborated OP.C(Optical Proximity Correction), and high performance resist, we still can't give up for 248nm wave technology 130nm node and beyond. But there are some major challenges to reduce MEEF(Mask Error Effect Factor) and understand lens aberrations. This paper will try to find out mutual relationship between 248nm 0.8NA exposure lens aberration and actual patterns. Influence of lens aberration on patterning characteristic will be investigated by using in house simulation tool.