ASML Holding N.V.
Method of measuring a parameter of interest, device manufacturing method, metrology apparatus, and lithographic system

Abstract:

Methods and apparatus for measuring a parameter of interest of a target structure formed on substrate are disclosed. In one arrangement, the target structure comprises a first sub-target and a second sub-target. The first sub-target comprises a first bias and the second sub-target comprises a second bias. The method comprises determining the parameter of interest using a detected or estimated reference property of radiation at a first wavelength scattered from the first sub-target and a detected or estimated reference property of radiation at a second wavelength scattered from the second sub-target. The first wavelength is different to the second wavelength.