Source and mask optimization for stability of reticle and wafer stages

Abstract

The relative motion of the reticle stage and wafer stage caused by vibration during the scanning exposure process of the lithography machine is an important factor that affects the imaging quality under limited lithography ability. In this paper, the influence of the vibration of the lithography stage system on the lithography imaging quality is studied. The lithography model including the vibration error of the stage is taken into account in the framework of source and mask optimization (SMO). For the 193-nm immersion lithography machine, combined with different design patterns with a line width of 40 nm and different vibration states of the stage when the lithography machine is exposed, the SMO joint optimization research is carried out, and the robustness of the stage under the limit process after SMO optimization is explored. The research results show that the contrast and relative light intensity change of the limit design figure under the influence of moving standard deviation (MSD) will greatly affect the linewidth at the light intensity threshold and then affect the process window (PW). The SMO including MSD allows the MSD to change in the range of 0-6 nm without changing the PW.