Method and apparatus for determining surface layer thickness using continuous multi-wavelength surface scanning
US7271921B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 9, 2004 |
| Grant date | Sep 18, 2007 |
| Priority date | — |
| Expiry date | Jul 27, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/0633
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An inspection tool includes an illumination element for directing light beams onto a workpiece at differing wavelengths or at differing angles of incidence or combinations thereof. Such beams producing reflected light and scattered light optical signals. A scanning element and optical detector elements are provided. The optical detector elements receive reflected light signals and scattered light signals. Circuitry for receiving the reflected light signals and scattered light signals are used to determine thickness values for partially transmissive layers formed on the workpiece and correct for the effects of the thickness of the partially transmissive layer so that said signals can be used to identify and characterize defects of the workpiece. Moreover, the invention includes descriptions of methods for accomplishing such inspections.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.