公开(公告)号：US20170343390A1

公开(公告)日：2017-11-30

申请号：US15524263

申请日：2015-10-22

Applicant: ASML NETHERLANDS B.V.

Inventor： Wouter Onno PRIL ,  Jan Peter BAARTMAN ,  Allard Eelco KOOIKER ,  Suzanne Johanna, Antonetta, COSIJNS ,  Bryan TONG-MINH

IPC: G01D5/38 ,  G01B9/02 ,  G01B11/02 ,  G03F7/20

Abstract: An encoder includes an optical component and an enclosing device having a first surface portion and a second surface portion. The first surface portion is arranged to receive from an ambient environment a first radiation beam. The second surface portion is arranged to receive from the ambient environment a second radiation beam. The optical component is arranged to combine the first and second radiation beams. The enclosing device is arranged to propagate the first radiation beam along a first path. The first path is between the first surface portion and the optical component. The enclosing device is arranged to propagate the second radiation beam along a second path. The second path is between the second surface portion and the optical component. The enclosing device is arranged to enclose a space, so as to isolate the first path and the second path from the ambient environment.