Method of measuring a parameter of a lithographic process, metrology apparatus
US11099489B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 2019 |
| Grant date | Aug 24, 2021 |
| Priority date | — |
| Expiry date | Feb 19, 2040 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/9501
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The disclosure relates to measuring a parameter of a lithographic process and a metrology apparatus. In one arrangement, radiation from a radiation source is modified and used to illuminate a target formed on a substrate using the lithographic process. Radiation scattered from a target is detected and analyzing to determine the parameter. The modification of the radiation comprises modifying a wavelength spectrum of the radiation to have a local minimum between a global maximum and a local maximum, wherein the power spectral density of the radiation at the local minimum is less than 20% of the power spectral density of the radiation at the global maximum and the power spectral density of the radiation at the local maximum is at least 50% of the power spectral density of the radiation at the global maximum.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.