Method for measuring an effect of a wavelength-dependent measuring light reflectivity and an effect of a polarization of measuring light on a measuring light impingement on a lithography mask
US12174546B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 2022 |
| Grant date | Dec 24, 2024 |
| Priority date | — |
| Expiry date | Jul 27, 2042 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/95676
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
To measure an effect of a wavelength-dependent measuring light reflectivity RRet of a lithography mask, a measuring light beam is caused to impinge on said lithography mask within a field of view of a measuring apparatus. The measuring light has a wavelength bandwidth between a wavelength lower limit and a wavelength upper limit differing therefrom. The reflected measuring light emanating from an impinged section of the lithography mask is captured by a detector. A filter with a wavelength-dependent transmission within the wavelength bandwidth is introduced into a beam path of the measuring light beam between the measuring light source and the detector. The measuring light reflected by the lithography mask is captured again by the detector once the filter has been introduced. The wavelength-dependent reflectivity RRet, or an effect of the wavelength-dependent reflectivity RRet is determined on the basis of the capture results. In comparison with the prior art, this yields an improved method for measuring an effect of a measuring light reflectivity on a lithography mask. Additionally, a method for measuring an effect of a polarization of measuring light on a measuring light impingem…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.