Patent ID: 8208118
Filing Date: 2012-06-26
Classification: G03B,G03F

Abstract:
1. A method for determining exposure settings for a target field on a substrate in a lithographic exposure process, comprising: determining calibration data comprising a plurality of calibration positions including position of a calibration field in a first direction at the plurality of calibration positions in a second and third direction relative to the position of the calibration field, wherein the calibration data is measured using only a single level sensor; determining production data by establishing position of the target field on the substrate in the second and third direction; measuring position of the target field in the first direction at at least one measurement position relative to position of the target field in the second and third direction; comparing the at least one measurement position and the plurality of calibration positions; determining a first set of exposure settings based on the calibration data, wherein the calibration data relates to at least one of the plurality of calibration positions which differs from the at least one measurement position; determining a second set of exposure settings based on the measured position of the target field; and correcting the second set of exposure settings based on the comparing and the first set of exposure settings to determine the exposure settings.