Patent ID: 9052595
Filing Date: 2015-06-09
Classification: G03F,G06F

Abstract:
1. A lithography method comprising: receiving a first mask fabricated by a first mask writer with a first grid table; receiving a second mask fabricated by a second mask writer with a second grid table; receiving a substrate with a set of baseline registration marks; forming a first set of registration marks on the substrate using the first mask and a first exposure tool; measuring a first set of overlay errors of the first set of registration marks with respect to the set of baseline registration marks; removing the first set of registration marks from the substrate; forming a second set of registration marks on the substrate using the second mask and a second exposure tool; measuring a second set of overlay errors of the second set of registration marks with respect to the set of baseline registration marks; generating a set of tool-induced overlay errors from the first set of overlay errors and the second set of overlay errors; and fabricating a device by using a third mask based on the set of tool-induced overlay errors.