Patent ID: 8039181

Claim:
A method, comprising: generating a plurality of sets of overlay correction data for a pair of a first lithography tool and a second lithography tool, said first lithography tool being used for imaging a first device layer on a substrate, said second lithography tool being used for imaging a second device layer on said substrate, said second device layer being spatially related to said first device layer, each of said plurality of sets of overlay correction data corresponding to a different status of at least one of the first and second lithography tools; obtaining process information associated with a product substrate to be processed in said second lithography tool, said product substrate having formed thereon said first device layer, said process information indicating a status of said first lithography tool when processing said product substrate; selecting one of said plurality of sets of overlay correction data that represents the status of said first lithography tool when processing said product substrate and a current status of said second lithography tool; and processing said product substrate in said second lithography tool on the basis of said selected one of the plurality of sets of overlay correction data.