公开(公告)号：US20180224759A1

公开(公告)日：2018-08-09

申请号：US15746164

申请日：2016-07-19

Applicant: ASML Holding N.V.

Inventor： Krishanu SHOME ,  Justin LIoyd KREUZER

IPC: G03F9/00 ,  G02B5/30 ,  G02B27/09

Abstract: An optical system for improving alignment measurement accuracy is discussed. The optical system includes first and second optical elements. The first optical element may be configured to change a first beam having a first polarization state into a second beam having a second polarization state. The second optical element may be configured to provide total internal reflection of the second beam and to change the second beam into a third beam having a third polarization state. The first, second, and third polarization states may be different from each other.