公开(公告)号：US12007590B2

公开(公告)日：2024-06-11

申请号：US16965172

申请日：2019-01-04

Applicant: ASML Netherlands B.V.

Inventor： Pieter Cristiaan De Groot ,  Johannes Jacobus Matheus Baselmans ,  Derick Yun Chek Chong ,  Yassin Chowdhury

IPC: G02B5/18 ,  G01M11/02 ,  G02B27/00 ,  G02B27/42 ,  G03F7/00

CPC classification number: G02B5/1819 ,  G01M11/0271 ,  G02B27/0012 ,  G02B27/4233 ,  G03F7/706

Abstract: A two-dimensional diffraction grating for a phase-stepping measurement system for determining an aberration map for a projection system comprises a substrate provided with a square array of through-apertures, wherein the diffraction grating is self-supporting. It will be appreciated that for a substrate provided with a square array of through-apertures to be self-supporting at least some substrate material is provided between each through-aperture and the adjacent through apertures. A method of designing a two-dimensional diffraction grating for a phase-stepping measurement system for determining an aberration map for a projection system comprises: selecting a general geometry for the two-dimensional diffraction grating, the general geometry having at least one parameter; and selecting values for the least one parameter that result in a grating efficiency map for the two-dimensional diffraction grating so as to control the contributions to a first harmonic of a phase stepping signal.

公开(公告)号：US20230251407A1

公开(公告)日：2023-08-10

申请号：US18003301

申请日：2021-06-17

Applicant: ASML Netherlands B.V.

Inventor： Derick Yun Chek Chong ,  Wouter Joep ENGELEN ,  Vyacheslav KACHKANOV ,  Vahid MOHAMMADI ,  Pieter Cristiaan DE GROOT

IPC: G02B5/18 ,  G03F7/20

CPC classification number: G02B5/1866 ,  G02B5/1857 ,  G03F7/70158 ,  G03F7/706 ,  G03F7/7085 ,  G02B2207/107

Abstract: A transmissive diffraction grating for a phase-stepping measurement system for determining an aberration map for a projection system comprises an absorbing layer. The diffraction grating is for use with radiation having a first wavelength (for example (EUV radiation). The absorbing layer is provided with a two-dimensional array of through-apertures. The absorbing layer is formed from a material which has a refractive index for the radiation having the first wavelength in the range 0.% to 1.04.