Lithographic apparatus and a method for determining a polarization property of a projection system using an adjustable polarizer and interferometric sensor
US9170498B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 2013 |
| Grant date | Oct 27, 2015 |
| Priority date | — |
| Expiry date | Mar 20, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/7085
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A lithographic apparatus includes an illumination system, support constructed to support patterning device, a projection system, an interferometric sensor and a detector. The interferometric sensor is designed to measure one or more wavefronts of a radiation beam projected by the projection system from an adjustable polarizer. The interferometric sensor includes a diffractive element disposed at a level of a substrate in the lithographic apparatus and a detector spaced apart from the diffractive element, the diffractive element being arranged to provide shearing interferometry between at least two wavefronts mutually displaced in a direction of shear. The detector is designed to determine, from the wavefront measurements, information on polarization affecting properties of the projection system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.