Imaging optics on scanner for SMO generation process

Abstract

The k 1 factor continues to be driven downward, in order to enable the 22-nm feature generation and beyond. Such a low k 1 factor tends to lead to extremely small process windows. For such demanding imaging challenges, it is not only necessary for each unit, contri buting to the imaging system, to be driven to its ultimate performance capability, but also that active techniques that can expand the process window and the robustness of the imaging against various kinds of imaging parameters be implemented. One such technique is source and mask optimization (SMO). In this paper, we study the effect of SMO. Furthermore, we discuss how to realize the SMO solution in the imaging system setup on the scanner. The setup process includes freeform pupilgram generation (source intensity distribution on the pupil) and pupilgram adjustment.