Source mask optimization based on design pattern library at 7nm technology node

It is possible to achieve mass production by multiple patterning technology combing with 193 immersion scanners at 7nm technology node. The application of freeform illumination source shapes is a key enabler for continued shrink using 193 nm immersion lithography with 1.35 NA. Source and mask optimization (SMO) is the important resolution enhancement technique (RET) to optimize a satisfied freeform source. Design pattern library can be used to cognize, manage and compare all the continuous changing and iterative physical designs. Our proposed methodology can improve SMO performance by taking advantages of post-color design pattern library and pattern selection method. And process window limiters are the important guidance to optimize parameters of SMO.