End facet protection for a radiation source and a method for use in metrology applications

US11287747B2 · kind B2 · utility

Assignee

• ASML NETHERLANDS B.V. · NL

Inventors

• Andrey Nikipelov · Eindhoven, NL
• Patrick Sebastian Uebel · Marloffstein, DE
• Amir ABDOLVAND · Erlangen, DE
• Sebastian Thomas Bauerschmidt · Wendelstein, DE
• Peter Maximilian Götz · Peising, DE
• Natallia Eduardauna Uzunbajakava · Eindhoven, NL

Key dates

• Filing date: Aug 3, 2020
• Grant date: Mar 29, 2022
• Expiry date: Aug 3, 2040

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70916
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A system and method for providing a radiation source is disclosed. In one arrangement, the radiation source includes a gas cell having a window, an optical fiber that is hollow and has an axial direction, an end thereof being enclosed within the gas cell and optically coupled to the window via an optical path, and a surface, disposed around the end of the optical fiber, and extending past the end of the optical fiber in the axial direction towards the window so as to limit one or more selected from: the exchange of gas between the optical path and the remainder of the gas cell, ingress of plasma towards or into the optical fiber, and/or radical flux towards etch-susceptible surfaces.