Illumination system, inspection apparatus including such an illumination system, inspection method and manufacturing method
US9753296B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 2015 |
| Grant date | Sep 5, 2017 |
| Priority date | — |
| Expiry date | Nov 23, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/0675
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an illumination system (12, 13) for a scatterometer, first and second spatial light modulators lie in a common plane and are formed by different portions of a single liquid crystal cell (260). Pre-polarizers (250) apply polarization to first and second radiation prior to the spatial light modulators. A first spatial light modulator (236-S) varies a polarization state of the first radiation in accordance with a first programmable pattern. Second spatial light modulator (236-P) varies a polarization state of the second radiation accordance with a second programmable pattern. A polarizing beam splitter (234) selectively transmits each of the spatially modulated first and second radiation to a common output path, depending on the polarization state of the radiation. In an embodiment, functions of pre-polarizers are performed by the polarizing beam splitter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.