Laser inspection using diffractive elements for enhancement and suppression of surface features
US7433053B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 8, 2002 |
| Grant date | Oct 7, 2008 |
| Priority date | — |
| Expiry date | Jul 8, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/47
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus for optical inspection of a sample includes a radiation source, adapted to irradiate a spot on the sample with coherent radiation, and collection optics, adapted to collect the radiation scattered from the spot so as to form a beam of scattered radiation. A diffractive optical element (DOE) is positioned to intercept the beam of scattered radiation and is adapted to deflect a first portion of the beam by a predetermined offset relative to a second portion of the beam, and then to optically combine the first portion with the second portion to generate a product beam. A detector is positioned to receive the product beam and to generate a signal responsive thereto, which is processed by a signal processor so as to determine an autocorrelation value of the product beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.