Surface defect inspection with large particle monitoring and laser power control
US10324045B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 2016 |
| Grant date | Jun 18, 2019 |
| Priority date | — |
| Expiry date | Dec 4, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/956
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and systems for reducing illumination intensity while scanning over large particles are presented herein. A surface inspection system determines the presence of a large particle in the inspection path of a primary measurement spot using a separate leading measurement spot. The inspection system reduces the incident illumination power while the large particle is within the primary measurement spot. The primary measurement spot and the leading measurement spot are separately imaged by a common imaging collection objective onto one or more detectors. The imaging based collection design spatially separates the image of the leading measurement spot from the image of the primary measurement spot at one or more wafer image planes. Light detected from the leading measurement spot is analyzed to determine a reduced power time interval when the optical power of the primary illumination beam and the leading illumination beam are reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.