Calibration of lithographic apparatus

摘要

System parameters are checked through self-assessment of a production wafer without a reference or a monitor wafer. In particular, exposure errors and substrate table positioning errors can be corrected for.

主权项

1. A method, comprising:
detecting errors in system parameters of a lithographic apparatus, wherein the detecting errors comprises:
performing a plurality of exposures on a substrate, each exposure being carried out on an exposure area on the substrate and forming one or more markers within the exposure area, wherein neighboring exposure areas share at least one overlapping region; andmeasuring the overlay between the markers formed from the neighboring exposures in the overlapping regions and measuring the positions of the markers across the substrate; combining differences in the measured positions of the markers between exposures in the overlapping regions with the measured positions of the other markers to obtain absolute values of system parameter errors; and deriving calibration correction factors from the obtained absolute values of system parameter errors.