公开(公告)号：US10691030B2

公开(公告)日：2020-06-23

申请号：US16192853

申请日：2018-11-16

Applicant: ASML NETHERLANDS B.V.

Inventor： Frank Staals ,  Eric Jos Anton Brouwer ,  Carlo Cornelius Maria Luijten ,  Jean-Pierre Agnes Henricus Marie Vaessen

IPC: G03F7/20 ,  G01N21/956 ,  G01N21/47

Abstract: A focus metrology target includes one or more periodic arrays of features. A measurement of focus performance of a lithographic apparatus is based at least in part on diffraction signals obtained from the focus metrology target. Each periodic array of features includes a repeating arrangement of first zones interleaved with second zones, a feature density being different in the first zones and the second zones. Each first zone includes a repeating arrangement of first features. A minimum dimension of each first feature is close to but not less than a resolution limit of the printing by the lithographic apparatus, so as to comply with a design rule in a given a process environment. A region of high feature density may further include a repeating arrangement of larger features.