Mark-detection methods and charged-particle-beam microlithography methods and apparatus comprising same

Methods and apparatus are disclosed for performing charged-particle-beam (CPB) microlithography, in which methods and apparatus certain position-measurement marks are detected by appropriate deflections of a charged particle beam. The deflections are performed using a primary deflector and a mark-scanning deflector. For example, the beam is deflected by the primary deflector to illuminate a position-measurement mark on the reticle and a corresponding position-measurement mark on the substrate. The position-measurement mark on the substrate is scanned by minute deflections of the beam as performed by the mark-scanning deflector. Meanwhile, charged particles backscattered from the position-measurement mark on the substrate (as the mark is being scanned) are captured and detected by a detector. The marks are detected at timing moments during normal operation of the primary deflector. Thus, during detection of the marks, the resulting positional determinations are less affected by extraneous variables such as changes in temperature and/or hysteresis of the primary deflector.