INSPECTION METHOD AND APPARATUS, LITHOGRAPHIC APPARATUS, LITHOGRAPHIC PROCESSING CELL AND DEVICE MANUFACTURING METHOD

摘要

INSPECTION METHOD AND APPARATUS, LITHOGRAPHIC APPARATUS,LITHOGRAPHIC PROCESSING CELL AND DEVICE MANUFACTURING METHOD In a scatterometric method differential targets with different sensitivities to parameters of interest are printed in a calibration matrix and difference spectra obtained. principal component analysis is applied to the difference spectra to obtain a calibration function that is less sensitive to variations in the underlying structure than a calibration function obtained from spectra obtained from a single target. Figure 1a