ASML Holding N.V.
Method of measuring a parameter of a device manufacturing process, metrology apparatus, substrate, target, device manufacturing system, and device manufacturing method

Abstract:

A method of measuring a parameter of a device manufacturing process is disclosed. The method includes measuring a target on a substrate by illuminating the target with measurement radiation and using an optical apparatus to detect the measurement radiation scattered by the target. The target has a target structure having a first periodic component and a second periodic component. The optical apparatus receives radiation resulting from diffraction of the measurement radiation from the target structure. The received radiation includes at least one diffraction order that would not be received from diffraction of the measurement radiation from the first periodic component alone nor from diffraction of the measurement radiation from the second periodic component alone.