Integration of an optical height sensor in mask inspection tools
US12360058B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 2021 |
| Grant date | Jul 15, 2025 |
| Priority date | — |
| Expiry date | Oct 4, 2042 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/95676
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A photomask-inspection system includes a vacuum chamber and a stage, disposed in the vacuum chamber, to support a photomask and to translate the photomask horizontally and vertically. The system also includes an EUV objective, disposed in the vacuum chamber, to collect EUV light from the photomask to inspect the photomask for defects and an optical height sensor, at least partially disposed in the vacuum chamber, to measure heights on a surface of the photomask. The system further includes a stage controller to translate the stage horizontally and vertically in accordance with a focal map for the photomask produced using the measured heights on the surface of the photomask.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.