Patent ID: 6883158

Claim:
A method for predicting and correcting geometrical errors in lithography using masks, including large-area photomasks or reticles, and exposure stations, including wafer steppers or projection aligners, printing the pattern of said masks on a workpiece, including a display panel or a semiconductor wafer, comprising the steps of providing a mask substrate, providing a pattern data file, providing a mask writer for writing said pattern onto said mask substrate, collecting information about the mask writer or the mask writer and any of the mask substrate and the exposure station; predicting from said information distorsions that will occur in the pattern, when it is subsequently printed on the workpiece calculating from said prediction a correction map to diminish said predicted distorsion, and exposing said pattern onto said mask substrate while applying said correction map for said distorsions; wherein said information about the mask writer includes information relating to at least one of a mask blank clamping structure, a mask writer exposure, a mask writer process and a mask writer pellicalizing; wherein said collected information further includes information about at least one error source selected from a group of error sources including: gravity and bending errors from mask blank clamping, non-uniformity errors in the mask blank exposure, time effect errors in the mask blank exposure, stage errors in the mask blank exposure, beam and grid effect errors in the mask blank exposure, stray exposure errors, non-uniformity errors in the mask writer process, complete relief of resist stress errors, partial relief of chrome stress errors and bending errors from pellicle mount.