Optics: measuring and testing – By light interference – For dimensional measurement
Reexamination Certificate
2008-02-28
2010-02-23
Chowdhury, Tarifur (Department: 2886)
Optics: measuring and testing
By light interference
For dimensional measurement
C356S503000
Reexamination Certificate
active
07667852
ABSTRACT:
In one embodiment, an interferometer system comprises an unequal path interferometer assemble comprising; a first reference flat having a first length L1in a first dimension, a second reference flat having a second length L2in the first dimension, a cavity D1defined by a distance between the first reference flat and the second reference flat, and a receptacle to receive an object in the cavity such that an optical path remains open between the first reference flat and the second reference flat, and a radiation targeting assembly to direct a collimated radiation beam to the interferometer assembly, a radiation collecting assembly to collect radiation received from the interferometer assembly, and a controller comprising logic to; vary a wavelength of the collimated radiation beam, record interferograms formed by a plurality of surfaces, extract phases of each of the interferograms for each of the plurality of surfaces to produce multiple phase maps, and determine each phase map from its corresponding interferogram, using a weighted least-square algorithm.
REFERENCES:
patent: 6847458 (2005-01-01), Freischlad et al.
patent: 6885461 (2005-04-01), Tang
patent: 2008/0117436 (2008-05-01), Altenberger et al.
Chowdhury Tarifur
Hansen Jonathan M
KLA-Tencor Corporation
Luedeka Neely & Graham P.C.
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