Design method for wafer alignment marks with low alignment position deviation under process-induced asymmetry.

High-precision wafer alignment is a key technology for achieving high overlay accuracy in advanced-node semiconductor manufacturing. In immersion, extreme ultraviolet (EUV), and high-NA EUV lithography, asymmetry in alignment mark structures, introduced by processes, such as chemical-mechanical polishing, is a primary cause of alignment position deviation (APD), which significantly degrades overlay accuracy. To address this issue at its root, this paper presents a systematic design methodology for segmented grating alignment marks based on multi-objective optimization. The mark geometry is parameterized and coupled with finite-difference time-domain simulations. A non-dominated sorting genetic algorithm (NSGA-II) is employed to simultaneously maximize diffraction efficiency and minimize APD under asymmetric deformation. Optimization results for two design examples confirm the effectiveness and feasibility of the proposed approach.