Zygo Corporation

Other

Kuchel, Michael

Leslie Ludwig Deck

Peter J De Groot

Xavier Colonna De Lega

Jan Liesener

Mark Davidson

Carl A Zanoni

Michael Schroeder

James F Biegen

Peter De Groot

David L Kent

Robert M Carangelo

Phillip H Malyak

Chris Koliopoulos

Michael Küchel

Robert Smythe

Michael Lowell Holmes

James W Kramer

David Stephenson

Alexander D Wesley

Edward J Gratix

Stephen H Chakmakjian

Jan Liesner

Edward J Gratrix

A method for measuring a bond gap includes receiving a light beam at a first interferometer cavity and a reference interferometer cavity, in which the first interferometer cavity is defined by a first surface and a contact interface, and the contact interface is defined by a contact gap less than 1 μm. The method includes determining a first interference amplitude of the first interferometer cavity and a second interference amplitude of the reference interferometer cavity by applying wavelength tuning and spectral analysis to measured intensities of light from the first interferometer cavity and the reference interferometer cavity. The contact gap is determined based on a ratio of the first interference amplitude and the second interference amplitude and information about a mapping between various interference amplitude ratios and expected contact gap values.

Optical contact metrology

A method for measuring a property of a test object with an interferometer includes: a) providing calibration information relating a focus setting for the interferometer to a position of the test object relative to a reference surface of the interferometer; b) determining the position of the test object relative to the reference surface; and c) using the interferometer to collect interferometric images of the test object for use in measuring the property of the test object.

Method and apparatus for optimizing the optical performance of interferometers

Interferometric method and apparatus using calibration information relating a focus setting to a test object position

Method and apparatus for determining the wavelength of a light beam are provided. An input light beam is received, and light from the input light beam is distributed to multiple channels. At a first pair of interferometer cavities that has a first free spectral range, two of the multiple channels of light are received. The intensity of light reflected from the first pair of cavities is measured, and a first estimate of the wavelength or optical frequency of the input light beam is determined based on measurements of interference signals from the first pair of cavities and an initial estimate of the wavelength or optical frequency. At a second pair of cavities that has a second free spectral range smaller than the first free spectral range, another two of the multiple channels of light are received. The intensity of light from the second pair of cavities is measured, and a second estimate of the wavelength or optical frequency of the input light beam is determined based on the first estimate and measurements of interference signals from the second pair of cavities, in which the second estimate is more accurate than the first estimate.

Wavemeter using pairs of interferometric optical cavities

Techniques for removing interferometry signal phase variations caused by distortion and other effects in a multi-layer stack include: providing an electronic processor sample interferometry data acquired for the stack using a low coherence imaging interferometry system; transforming, by the electronic processor, the sample interferometry data to a frequency domain; identifying a non-linear phase variation from the sample interferometry data in the frequency domain, in which the non-linear phase variation is a result of dispersion introduced into a measurement beam by the test sample; and removing the non-linear phase variation from the sample interferometry data thereby producing compensated interferometry data.

Metrology of multi-layer stacks

An optical method for determining an orientation of surface texture of a mechanical part includes: i) acquiring data for a first areal surface topography image using a surface topography measurement instrument, wherein the first image corresponds to a first field of view of the mechanical part for the surface topography measurement instrument; ii) rotating the mechanical part with respect to a rotation axis provided by a rotatable mount used to secure the mechanical part to provide a second field of view of the mechanical part for the surface topography measurement instrument, wherein the first and second fields of view overlap to provide image information about a common region of the mechanical part; iii) acquiring data for a second areal surface topography image using the surface topography measurement instrument, wherein the second image corresponds to the second field of view; and iv) processing the data from the images.

Surface topography apparatus and method

Method include using an apparatus to measure a first surface field, at a first surface of the apparatus, of an artifact having one or more surface features with known topography. The method includes determining a first focus metric at the first surface based on at least a portion of a first surface profile containing the one or more surface features. Methods include digitally transforming, the first surface field into a second surface field at a second surface of the apparatus, deriving, a second surface profile from the second surface field and computing a second focus metric for the second surface profile, and determining, based on two or more focus metric values, an optimum surface for evaluating the instrument transfer function. Method include determining the instrument transfer function of the apparatus based on at least a portion of the surface profile derived from the surface field of the optimum surface.

A method for determining characteristics of a test cavity, the method includes for each of a plurality of optical frequencies within a bandwidth of a tunable laser, measuring interference signals from the test cavity and a reference cavity having a known characteristic. The method includes determining values for the plurality of optical frequencies from the measured interference signals from the reference cavity and the known characteristic of the reference cavity, and determining the characteristic of the test cavity using the determined values of the plurality of optical frequencies.

Precision positioning system using a wavelength tunable laser

Determining information about a degree of freedom of rigid body motion of an encoder scale includes: directing a first beam toward an encoder scale, in which the first beam diffracts from an encoder scale; combining a diffracted component of the first beam with a second beam to form an interfering output beam; monitoring changes in the output beam as a function of a wavelength of the first and second beams; and determining the information about a degree of freedom of rigid body motion of the encoder scale based on changes in the output beam as a function of the wavelength.

Interferometric encoders using spectral analysis

An interferometry system for monitoring changes in the position of an object, the system includes a spectrally broadband light source, a sensor module having an interferometer that direct portions of the light received from the source along separate paths. The system includes an intensity monitor having a detector configured to measure the intensity of additional light derived from the source and to produce a monitor output signal. The system includes an electronic processing module to process a sensor output signal based on the monitor output signal to account for intensity fluctuations in light output by the source, and determine information about the changes in the position of the object. The intensity monitor is configured to characterize the intensity fluctuations as a function of wavelength or intensity fluctuations that are spectrally correlated.

Position monitoring system with reduced noise

A method for determining information about changes along a degree of freedom of an encoder scale includes directing a first beam and a second beam along different paths and combining the first and second beams to form an output beam, where the first and second beams are derived from a common source, the first and second beams have different frequencies, where the first beam contacts the encoder scale at a non-Littrow angle and the first beam diffracts from the encoder scale at least once; detecting an interference signal based on the output beam, the interference signal including a heterodyne phase related to an optical path difference between the first beam and the second beam; and determining information about a degree of freedom of the encoder scale based on the heterodyne phase.

Interferometric encoder systems

A system includes an interference microscope having one or more optical elements arranged to image a test object to an image plane by combining test light from the test object with reference light from a reference object to form an interference pattern at the image plane, wherein the test and reference light are derived from a common broadband light source. The system includes a scanning stage configured to scan an optical path difference (OPD) between the test and reference light, a multi-element detector positioned at the image plane and configured to record the interference pattern for each of a series of OPD increments and to generate multiple interferometry signals each having a fringe carrier frequency indicative of changes in the OPD as the OPD is scanned, where there is phase diversity among the interferometry signals, and an electronic processor coupled to the multi-element detector and scanning stage and configured to process the interference signals based on the phase diversity to determine information about the OPD increments having sensitivity to perturbations to the OPD increments at frequencies greater than the fringe carrier frequency.

Low coherence interferometry with scan error correction

Apparatus include a microscope including an objective and a stage for positioning a test object relative to the objective, the stage being moveable with respect to the objective, and a sensor system, that includes a sensor light source, an interferometric sensor configured to receive light from the sensor light source, to introduce an optical path difference (OPD) between a first portion and a second portion of the light, the OPD being related to a distance between the objective lens and the stage, and to combine the first and second portions of the light to provide output light, a detector configured to detect the output light from the interferometric sensor, a fiber waveguide configured to direct light between the sensor light source, the interferometric sensor and the detector, a tunable optical cavity in a path of the light from the sensor light source and the interferometric sensor, and an electronic controller in communication with the detector, the electronic controller being configured to determine information related to the OPD based on the detected output light.

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Middletown, CT, United States of America

Leslie Ludwig Deck