Asml Netherlands B.v.

Mitutoyo Corporation

Maarten Jozef Jansen

Engelbertus Antonius Fransiscus Van Der Pasch

Teunis Jan Ikkink

Frank Auer

Suzanne Johanna Antonetta Geertruda Cosijns

Frans De Nooij

Ivo Widdershoven

Katherine Mary Medicus

Manoj Kumar Mridha

Ping Liu

Koen Govert Olivier Van De Meerakker

An interferometer system includes an optics system configured to allow a first light beam to travel along a measurement path including a target, and a second light beam to travel along a fixed reference path excluding the target; and a signal generator configured to introduce a power-modulated optical signal in the measurement path or the reference path to determine jitter caused by components of the interferometer system downstream of the signal generator.

Interferometer system, positioning system, a lithographic apparatus, a jitter determination method, and a device manufacturing method

Interferometer system including a first detector for receiving a first measurement beam travelling to a reference surface; a second detector for receiving a second measurement beam travelling to the target surface; a reference variable delay path and/or measurement variable delay path and a delay path controller for adapting a delay length. A reference spectral coherence pulse occurs at the first detector, at a reference coherence arrangement and a measurement spectral coherence pulse at the second detector at a measurement coherence arrangement. A control unit receives a reference coherence signal from the first detector, and a measurement coherence signal from the second detector, and determines a zero-position of the target surface based on the reference coherence signal and the measurement coherence signal, and based on the reference coherence arrangement and the measurement coherence arrangement and/or a delay path difference between the reference coherence arrangement and the measurement coherence arrangement.

Interferometer system and lithographic apparatus

The invention provides a positioning system to determine an absolute position of a moveable target relative to a reference, comprising an interferometer system with a first light source to emit light at a fixed frequency and a second light source to emit light at at least two different frequencies. The positioning system is configured to determine, based on movement of the target, a phase difference curve associated with a first frequency of the second light source and a phase difference curve associated with a second frequency of the second light source as a function of a phase difference associated with the fixed frequency of the first light source and to determine a cross-point to determine the absolute position of the moveable target. The invention also relates to a lithographic apparatus and corresponding method.

Positioning system, a lithographic apparatus, an absolute position determination method, and a device manufacturing method

A compact dual pass interferometer for a plane mirror interferometer configured to receive an input radiation beam from a light source. An optical component has a partially reflective surface arranged to reflect a first portion of the input radiation beam to follow a first optical path directed towards an output terminal and further arranged to transmit a second portion of the input radiation beam to follow a second optical path, directed towards a first location on a reflective target surface and back to the partially reflective surface, then to a second location on the reflective target surface and back to the partially reflective surface, whereupon the second optical path is directed through the partially reflective surface to be recombined with the first optical path to provide a recombined optical path configured to provide an output radiation beam. The output terminal configured to deliver the output radiation beam to a detector.

Compact dual pass interferometer for a plane mirror interferometer

The invention provides a method for calibration of an optical measurement system, which may be a heterodyne interferometer system, wherein a first optical axis and a second optical axis have a different optical path length, the method comprises:measuring a first measurement value along the first optical axis using a first measurement beam,measuring a second measurement value along the second optical axis using a second measurement beam,changing a wavelength of the first measurement beam and the second measurement beam,measuring a further first measurement value along the first optical axis using the first measurement beam with changed wavelength, measuring a further second measurement value along the second optical axis using the second measurement beam with changed wavelength,determining a cyclic error of the optical measurement system on the basis of the measured values, andstoring a corrective value based on the cyclic error.

Method for calibration of an optical measurement system and optical measurement system

An interferometer system including: an optical system arranged to split a radiation beam from a laser source into a first beam along a first optical path and a second beam along a second optical path, and recombine the first beam and the second beam to a recombined beam, a detector to receive the recombined beam and to provide a detector signal based on the received recombined beam, and a processing unit, wherein a first optical path length of the first optical path and a second optical path length of the second optical path have an optical path length difference, and wherein the processing unit is arranged to determine a mode hop of the laser source on the basis of a phase shift in the detector signal.

Interferometer system, method of determining a mode hop of a laser source of an interferometer system, method of determining a position of a movable object, and lithographic apparatus

The invention provides a stage system comprising a stage (ST) which is movable in respect of a reference structure. One of the stage and the reference structure comprises a reflective surface (REFS). An optical position sensor (IF) is arranged at the other one of the stage and the reference structure and is configured to determine a position of the reflective surface relative to the optical position sensor. An optical shape sensor (IF) is configured to determine a shape of the reflective surface. The stage system further comprises a position measurement controller configured to derive a stage position of the stage from the position of the reflective surface relative to the optical position sensor and from the shape of the reflective surface as determined by the optical shape sensor.

Stage system and lithographic apparatus

The invention provides a wavelength tracking system comprising a wavelength tracking unit and an interferometer system. The wavelength tracking unit has reflection surfaces at stabile positions providing a first reflection path with a first path length and a second reflection path with a second path length. The first path length is substantially larger than the second path length. The interferometer system comprises: a beam splitter to split a light beam in a first measurement beam and a second measurement beam; at least one optic element to guide the first measurement beam, at least partially, along the first reflection path and the second measurement beam, at least partially, along the second reflection path; a first light sensor arranged at an end of the first reflection path to receive the first measurement beam and to provide a first sensor signal on the basis of the first measurement beam; a second light sensor arranged at an end of the second reflection path to receive the second measurement beam and to provide a second sensor signal on the basis of the second measurement beam; and a processing unit to determine a wavelength or change in wavelength on the basis of the first sensor signal and the second sensor signal.

Wavelength tracking system, method to calibrate a wavelength tracking system, lithographic apparatus, method to determine an absolute position of a movable object, and interferometer system

An interferometer system, including a heterodyne interferometer and a processing system. The heterodyne interferometer is arranged to provide a reference signal and a measurement signal. The reference signal has a reference phase. The measurement signal has a measurement phase and an amplitude. The processing system is arranged to determine a cyclic error of the heterodyne interferometer based on the reference phase, the measurement phase and the amplitude.

Cyclic error measurements and calibration procedures in interferometers

A position measurement system configured to measure a position of an object, the system including: a displacement interferometer having a first capture range; a time-of-flight sensor having a second capture range that is larger than the first capture range and having an inaccuracy that is smaller than the first capture range; and a processing unit, wherein the position measurement system has a zeroing mode in which the processing unit is configured to determine a coarse position of the object within the second capture range based on an output from the time-of-flight sensor, and in which the processing unit is configured to determine a fine position of the object based on the determined coarse position and an output from the displacement interferometer.

Position measurement system, zeroing method, lithographic apparatus and device manufacturing method

An interferometric displacement measuring system operable to measure displacements of a movable object of the lithographic apparatus in a first direction using a measurement beam of radiation and a reflector. The reflector being substantially planar and substantially perpendicular to the first direction. Calibration is obtained using a first set of measurements of the angular position movable object. A phase offset in the measurement beam is affected. A second set of measurements of the angular position of the movable object is obtained. The interferometric displacement measuring system is calibrated based on the first and second sets of measurements.

Lithographic apparatus, device manufacturing method, and method of calibrating a displacement measuring system

The invention relates to a method and an apparatus for determining a height of a number of spatial positions on a sample, defining a height map of a surface of said sample. The method can involve irradiating the surface of the sample with light including a spatial periodic pattern in a direction perpendicular to an optical axis and moving parallel to the pattern, scanning the surface in the direction of the optical axis for each position of the surface and detecting the light reflected by the sample by a detector during the scanning. In any scanning position, only a single image is taken, and the scanning speed has a predetermined relation to the phase of the periodic pattern. Analyzing an output signal of the detector can involve, for each spatial position of the detector, determining of an amplitude of the signal detected during the scanning and determining a scanning location where the amplitude is maximal.

Method and apparatus for determining a height of a number of spatial positions on a sample

The invention relates to a method and an apparatus for determining the height of a number of spatial positions on the sample, defining a height map of a surface through interferometry with a broadband light source. The method can involve for each spatial position: obtaining a correlogram during scanning of the surface plane of the objective and estimating the point of the correlogram where an amplitude of the correlogram is at its maximum, thus determining an approximation of the height of the spatial position on the sample. The estimation of the value where the correlogram has its maximum can involve subjecting the correlogram to a Fourier transform, subjecting the Fourier transformed signal to a filter, subjecting the filtered signal to an inverse Fourier transform, and calculating the location of the center of mass of the inversed filtered Fourier transformed signal.

Method and apparatus for determining the height of a number of spatial positions on a sample defining a profile of a surface through white light interferometry

The invention relates to an apparatus and a method for determining a height map of a surface of an object. The apparatus can include positioning means for the object, a light source, an optical detector for converting the received light into electrical signals, first optics for directing light from the light source to the surface and for directing the light from the surface to the optical detector, a beam splitter located between the first optics and the surface, a reference mirror, second optics located between the beam splitter an the mirror for directing the light from the beam splitter to the mirror and from the mirror to the beam splitter, scanning means, processing means that converts the signal from the optical detector into a height map. The beam splitter can be a polarizing beam splitter. A controllable polarization controller can be located between the light source and the first optics.

Apparatus for determining a height map of a surface through both interferometric and non-interferometric measurements

An interferometer includes a light source, adapted to generate a coherent light beam, a detector adapted to analyze the phase difference of optical light beams, a location unit for locating an object to be measured, a first optical path from the light source to the object and a second optical path from the object to the detector. The first and the second optical path have a common section adjacent to the object. An optical polarization modulator has been arranged in the first path.

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Casteren, Netherlands

Maarten Jozef Jansen