公开(公告)号：WO2019086397A1

公开(公告)日：2019-05-09

申请号：PCT/EP2018/079614

申请日：2018-10-30

Applicant: ASML NETHERLANDS B.V.

Inventor： BAEK, Jonghoon ,  ABRAHAM, Mathew, Cheeran

IPC: G03F7/20 ,  H05G2/00

CPC classification number: G03F7/70925 ,  G03F7/70033 ,  H05G2/00

Abstract: A method is described to clean a surface of an optic (115) within a chamber (125) of an extreme ultraviolet (EUV) light source (100). The chamber is held at a pressure below atmospheric pressure. The method includes generating a material in a plasma state at a location adjacent to the optic surface (110) and within the chamber, the generating comprising transforming a native material (135) that is already present within the vacuum chamber and adjacent the optic surface from a first state into the plasma state (130). The plasma state of the material includes free radicals of the material. The material in the plasma state is generated by enabling the material in the plasma state to pass over the optic surface to remove debris (107) from the optic surface without removing the optic from the EUV light source.