公开(公告)号：US10725381B2

公开(公告)日：2020-07-28

申请号：US16117589

申请日：2018-08-30

Applicant: ASML Netherlands B.V.

Inventor： Sietse Thijmen Van Der Post ,  Stefan Michael Bruno Bäumer ,  Peter Danny Van Voorst ,  Teunis Willem Tukker ,  Ferry Zijp ,  Han-Kwang Nienhuys ,  Jacobus Maria Antonius Van Den Eerenbeemd

IPC: G21K1/00 ,  G03F7/20 ,  G21K7/00 ,  G21K1/06 ,  G02B17/04 ,  G01N21/47 ,  G01N21/95

Abstract: An optical system (OS) for focusing a beam of radiation (B) on a region of interest in a metrology apparatus is described. The beam of radiation (B) comprises radiation in a soft X-ray or Extreme Ultraviolet spectral range. The optical system (OS) comprises a first stage (S1) for focusing the beam of radiation at an intermediate focus region. The optical system (OS) comprises a second stage (S2) for focusing the beam of radiation from the intermediate focus region onto the region of interest. The first and second stages each comprise a Kirkpatrick-Baez reflector combination. At least one reflector comprises an aberration-correcting reflector.