Low coherence grazing incidence interferometry for profiling and tilt sensing
US7289224B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 2004 |
| Grant date | Oct 30, 2007 |
| Priority date | — |
| Expiry date | Aug 5, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical system includes a photolithography system, a low coherence interferometer, and a detector. The photolithography system is configured to illuminate a portion of an object with a light pattern and has a reference surface. The low coherence interferometer has a reference optical path and a measurement optical path. Light that passes along the reference optical path reflects at least once from the reference surface and light that passes along the measurement optical path reflects at least once from the object. The detector is configured to detect a low coherence interference signal including light that has passed along the reference optical path and light that has passed along the measurement optical path. The low coherence interference signal is indicative of a spatial relationship between the reference surface and the object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.