公开(公告)号：US11703771B2

公开(公告)日：2023-07-18

申请号：US17773003

申请日：2020-10-12

Applicant: ASML Holding N.V. ,  ASML Netherlands B.V.

Inventor： Ali Alsaqqa ,  Fadi El-Ghussein ,  Lambertus Gerardus Maria Kessels ,  Roxana Rezvani Naraghi ,  Krishanu Shome ,  Timothy Allan Brunner ,  Sergei Sokolov

IPC: G03F7/20 ,  G03F9/00

CPC classification number: G03F9/7019 ,  G03F9/7076

Abstract: A calibration system includes a plate, a fixed alignment mark, and a variable diffraction grating. The plate is adjacent to a wafer alignment mark disposed on a wafer. The fixed alignment mark is disposed on the plate and is configured to act as a reference mark for an initial calibration of the calibration system. The variable diffraction grating is disposed on the plate and includes a plurality of unit cells configured to form a plurality of variable alignment marks. The variable diffraction grating is configured to calibrate a shift-between-orders of one of the variable alignment marks and the fixed alignment mark.