Grazing and normal incidence interferometer having common reference surface
US8786842B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 2007 |
| Grant date | Jul 22, 2014 |
| Priority date | — |
| Expiry date | Aug 9, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for inspecting specimens such as semiconductor wafers is provided. The system provides scanning of dual-sided specimens using a diffraction grating that widens and passes nth order (n>0) wave fronts to the specimen surface and a reflective surface for each channel of the light beam. Two channels and two reflective surfaces are preferably employed, and the wavefronts are combined using a second diffraction grating and passed to a camera system having a desired aspect ratio. The system preferably comprises a damping arrangement which filters unwanted acoustic and seismic vibration, including an optics arrangement which scans a first portion of the specimen and a translation or rotation arrangement for translating or rotating the specimen to a position where the optics arrangement can scan the remaining portion(s) of the specimen. The system further includes-means for stitching scans together, providing for smaller and less expensive optical elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.