Apparatus and method for dual spot inspection of repetitive patterns
US6943898B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 2003 |
| Grant date | Sep 13, 2005 |
| Priority date | — |
| Expiry date | Oct 6, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/95607
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus for optical assessment of a sample includes a radiation source, adapted to generate a beam of coherent radiation, and traveling lens optics, adapted to focus the beam so as to generate first and second spots on a surface of the sample and to scan the spots together over the surface. The distance between the first and second spots is responsive to a pitch of a repetitive pattern of the sample. Collection optics are positioned to collect the radiation scattered from the first and second spots and to focus the collected radiation so as to generate an interference pattern. A detector detects a change in the interference pattern.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.