Zygo Corporation

Peter De Groot

Henry Allen Hill

Leslie Ludwig Deck

Xavier Colonna De Lega

Jan Liesener

Carl A Zanoni

Frank C Demarest

Mark Davidson

James W Kramer

Henry A Hill, Jr

In general, in one aspect, the invention features a system including a light source, a plurality of interferometers configured to receive light from the light source and to form output light, each interferometer including a first optic and a second optic, the first and second optics configured to be mounted on a first object and a second object, respectively, where first object is moveable with respect to the second object, the first and second optics being configured introduce an optical path length difference (OPD) between two components of the light to form the output light, the OPD being related to the position of the first optic with respect to the second optic. The system further includes a plurality of detectors configured to detect the output light from the interferometers, a modulation apparatus in the optical path between the light source and the detectors, the modulation apparatus being configured to vary an OPD between the two components of the light over a range including OPDs for which a net OPD of the output light from at least one of the interferometers at the detectors is zero, a plurality of waveguides configured to direct light between the interferometers, the modulation apparatus, and the detectors, and an electronic controller in communication with the detectors, the electronic controller being configured to determine information about a position of the first object based on the detected output light from at least one of the interferometers.

Interferometer system for monitoring an object

The invention features a surface profiling method including: collecting interferometric data related to a surface profile of a measurement object; and calculating the surface profile based on the collected interferometric data and at least one value indicative of dispersion in the phase change on reflection (PCOR) of the profiled surface of the measurement object. The invention also features a surface profiling system including: an interferometry system which during operation provides interferometric data related to a surface profile of a measurement object; and an electronic processor coupled the interferometry system, wherein during operation the electronic processor calculates the surface profile based on the interferometric data and at least one parameter indicative of dispersion in the phase change on reflection (PCOR) of the profiled surface of the measurement object.

Height scanning interferometer for determining the absolute position and surface profile of an object with respect to a datum

The invention features methods and systems for interferometrically profiling a measurement object having multiple reflective surfaces, e.g., to profile a selected one of the multiple reflective surfaces. The methods and systems involve: positioning the measurement object within an unequal path length interferometer (e.g., a Fizeau interferometer) employing a tunable coherent light source; recording an optical interference image for each of multiple wavelengths of the light source, each image including a superposition of multiple interference patterns produced by pairs of wavefronts reflected from the multiple surfaces of the measurement object and a reference surface; and extracting phases of a selected one of the interference patterns from the recorded images by using a phase-shifting algorithm that is more sensitive (e.g., at least ten times more sensitive) to a wavelength-dependent variation in the recorded images caused by the selected interference pattern than to wavelength-dependent variations in the recorded images caused by the other interference patterns.

Method and system for profiling objects having multiple reflective surfaces using wavelength-tuning phase-shifting interferometry

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Middletown, CT, United States of America

Peter De Groot