Measuring the shape and thickness variation of a wafer with high slopes
US7847954B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 2008 |
| Grant date | Dec 7, 2010 |
| Priority date | — |
| Expiry date | Feb 25, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/45
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system with two unequal path interferometers, with a first flat, a second flat, and a cavity between the first and second flats, a holder to receive an object in the cavity such that an optical path remains open between the first and second flats, and a motor coupled to the holder such that the object may be tilted in the cavity to allow for measurements of, and a radiation assembly to direct collimated radiation to the interferometer assembly, a collecting assembly to collect radiation received from the interferometer assembly, and a controller comprising logic to; vary a wavelength of the radiation, record interferograms, extract phases of the interferograms to produce phase maps, determine from each map areas with high slopes, tilt the holder to allow measurement of the high slope areas, and process measurement that covers the entire surface of the object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.