Optical element, lithographic apparatus including such an optical element, device manufacturing method, and device manufactured thereby
US8345223B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 2009 |
| Grant date | Jan 1, 2013 |
| Priority date | — |
| Expiry date | Oct 9, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG21K2201/067
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical element includes a first layer that includes a first material, and is configured to be substantially reflective for radiation of a first wavelength and substantially transparent for radiation of a second wavelength. The optical element includes a second layer that includes a second material, and is configured to be substantially absorptive or transparent for the radiation of the second wavelength. The optical element includes a third layer that includes a third material between the first layer and the second layer, and is substantially transparent for the radiation of the second wavelength and configured to reduce reflection of the radiation of the second wavelength from a top surface of the second layer facing the first layer. The first layer is located upstream in the optical path of incoming radiation with respect to the second layer in order to improve spectral purity of the radiation of the first wavelength.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.