Modeling studies on alternative EUV mask concepts for higher NA

This paper investigates the performance of different mask options for sub-13 nm EUV-lithography with a 4× demagnication and an NA of 0.45. The considered mask options include standard binary masks, standard attenuated phase-shift masks, etched attenuated phase-shift masks and embedded-shifter phase-shift masks. The lithographic performance of these masks is investigated and optimized in terms of mask efficiency, NILS, DoF, OPC-performance and telecentricity errors. A multiobjective optimization technique is used to identify the most promising mask geometry parameters.