Research of SMO process to improve the imaging capability of lithography system for 28nm node and beyond

The source-mask optimization (SMO) solution has become one of the most important branches of Resolution enhancement techniques (RET) to extend the imaging process window with next generation computation lithography, which improve the imaging capability of lithographic systems in the integrated circuit foundry manufacturing. Based on the SMO software RET Selection provided by Mentor Graphics Corporation, we have researched the SMO process to improve the imaging capability of lithographic systems for 28run node and beyond: choosing the key patterns, confirming the process window conditions and so on. In this paper, the parameters PV band, MEEF, NILS and DOF have been used to evaluate the free form illumination sources, and the final illumination source have been verified, which generated by ASML scanner.