Grazing and normal incidence interferometer having common reference surface
US9273952B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 22, 2014 |
| Grant date | Mar 1, 2016 |
| Priority date | — |
| Expiry date | Jul 22, 2034 |
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.