Charged-particle-beam microlithography apparatus including selectable systems for determining alignment-mark position, and device-fabrication methods utilizing same

摘要

Charged-particle-beam microlithography apparatus are disclosed that include a system for performing alignment of a reticle and a wafer. The wafer includes at least one alignment mark that is irradiated by a charged particle beam. The irradiated alignment mark produces backscattered electrons that are detected, resulting in a backscattered-electron (BSE) data signal. Among various candidate techniques for measuring the position of the alignment mark, the apparatus automatically selects (based on the BSE data signal) a particular technique that will provide the best accuracy under the prevailing conditions of measurement.