公开(公告)号：US09958790B2

公开(公告)日：2018-05-01

申请号：US15105349

申请日：2014-11-20

Applicant: ASML Netherlands B.V.

Inventor： Tjitte Nooitgedagt ,  Marc Jurian Kea

IPC: G03F7/20

CPC classification number: G03F7/70625 ,  G03F7/70466 ,  G03F7/70633 ,  G03F7/70683

Abstract: Disclosed is a method of measuring overlay between upper and lower layers on a substrate using metrology targets formed by a lithographic process. The lithographic process is of a multiple-patterning type whereby first and second distinct populations of structures are formed in a single one of said layers (L1) by respective first and second patterning steps. The metrology target (620) in the single one of said layers comprises a set of structures of which different subsets (642A, 642B) are formed in said first and second patterning steps. An overlay measurement on this target can be used to calculate a combined (average) overlay performance parameter for both of the first and second patterning steps.