Apparatus and method for detecting contamination within a lithographic apparatus
US7473916B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 16, 2005 |
| Grant date | Jan 6, 2009 |
| Priority date | — |
| Expiry date | Aug 8, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70916
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A lithographic apparatus that includes at least one optical surface exposed to a radiation beam, and a surface plasmon resonance measurement apparatus adjacent the optical surface that is configured to detect contamination of at least one optical surface of the lithographic apparatus. The measurement apparatus is located near or in close proximity to the optical surface to as to emulate and determine possible contamination without interfering with the radiation beam used to expose the optical surface. A radiation source for the measurement apparatus is configured to provide a probing beam of radiation having an angle of incidence. By measuring the surface plasmons and/or the angles of incidence of a reference optical surface in the measurement apparatus, contamination deposited on an optical surface in the lithographic apparatus may be inferred.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.