公开(公告)号：US20200319563A1

公开(公告)日：2020-10-08

申请号：US16753441

申请日：2018-08-23

Applicant: ASML NETHERLANDS B.V.

Inventor： Beniamino SCIACCA ,  Sanjaysingh LALBAHADOERSING ,  Jia WANG

IPC: G03F7/20 ,  G03F9/00

Abstract: A resonant amplitude grating mark has a periodic structure configured to scatter radiation incident on a surface plane of the alignment mark. The scattering is mainly by excitation of a resonant mode in the periodic structure parallel to the surface plane. The effective refractive indexes and lengths of portions of the periodic structure are configured to provide an optical path length of the unit cell in the direction of periodicity that equals an integer multiple of a wavelength present in the spectrum of the radiation. The effective refractive indexes and lengths of the portions are also configured to provide an optical path length of the second portion in the direction of periodicity that is equal to half of the wavelength present in the spectrum of the radiation.