Patent ID: 8248579

Claim:
A method, comprising: determining an overlay error, caused by local residual distortion in a patterning device, between a first part of a first pattern associated with the patterning device and a first part of a second pattern associated with the patterning device, the first and second patterns overlapping and the overlay error corresponding to forming the first and second patterns according to a suggested value for each of at least one process parameter determined based on an overlay correction model, wherein the at least one process parameter includes at least one of a lens parameter and a scan parameter; determining a value for the each of the at least one process parameter corresponding to a minimal overlay error between a second part of the first pattern and a second part of the second pattern by fitting the overlay correction model to data comprising the overlay error and the suggested value for the each of the at least one process parameter; and creating at least one of the second part of the first pattern and the second part of the second pattern according to the determined value for the each of the at least one process parameter.