Differential dose and focus monitor

摘要

A dose and focus monitor structure includes at least one complementary set of unit dose monitors and at least one complementary set of unit focus monitors. Each complementary set of unit dose monitors generate edges on a photoresist layer such that the edges move in opposite directions as a function of a dose offset. Each complementary set of unit focus monitors generates edges on the photoresist layer such that the edges move in opposite directions as a function of a focus offset. The dose and focus monitor structure generates self-compensating differential measurements of the dose offset and the focus offset such that the dose offset measurement and the focus offset measurement are independent of each other.

主权项

1. A reticle comprising a dose and focus monitor structure, said dose and focus monitor structure comprising:
at least one pair of unit dose monitors configured to print a first pair of printed shapes on a photoresist layer, upon lithographic exposure and development of said photoresist layer, said first pair of first printed shapes moving in opposite directions from positions corresponding to a nominal dose by a first offset distance that is proportional to a dose offset from said nominal dose; and at least one pair of unit focus monitors configured to print a second pair of printed shapes on said photoresist layer, upon lithographic exposure and development of said photoresist layer, said second pair of second printed shapes moving in opposite directions from positions corresponding to a nominal focus by a second offset distance that is proportional to a focus offset from said nominal focus, wherein a pair of unit dose monitors among said at least one pair of unit dose monitors have patterns that are mirror images of each other.