Simultaneous suppression of overlap errors and side-lobes in attenuated PSM lithography by rule-based OPC

Abstract

Problems of overlap errors and side-lobe printing by the design rule reduction in the lithography process using attenuated phase-shifting masks (attPSM) have been serious. Overlap errors and side-lobes can be simultaneously solved by the rule-based correction using scattering bars with the rules extracted from test patterns. Process parameters affecting the attPSM lithography simulation have been determined by the fitting method to the process data. Overlap errors have been solved applying the correction rules to the metal patterns overlapped with contact/via. Moreover, the optimal insertion rule of the scattering bars has made it possible to suppress the side-lobes and to get additional pattern fidelity at the same time.