Abstract: A polarized Raman Spectrometric system for defining parameters of a polycrystaline material, the system comprises a polarized Raman Spectrometric apparatus, a computer-controlled sample stage for positioning a sample at different locations, and a computer comprising a processor and an associated memory. The polarized Raman Spectrometric apparatus generates signal(s) from either small sized spots at multiple locations on a sample or from an elongated line-shaped points on the sample, and the processor analyzes the signal(s) to define the parameters of said polycrystalline material.

Abstract: Described herein is a method of evaluating artificial lighting of a surface. The method may comprise measuring a first lumen output at a first location on the surface at a first altitude. The method may further comprise photographing the surface from a second altitude to obtain an aerial photograph of the surface comprising a plurality of pixels, each pixel of the plurality of pixels having a second lumen output, and performing an altitude adjustment on the second lumen output to obtain a third lumen output. The method may comprise dividing the aerial photograph into a plurality of zones, each zone corresponding to a section of the surface. The method may further comprise establishing a user-defined threshold lumen output for each zone of the plurality of zones, and identifying a percentage of the total number of pixels in each zone which meets or exceeds the user-defined threshold lumen output.

Abstract: The embodiments herein relate to a method for deriving topography of an object surface. A linearly polarized light wave is directed towards the object surface and a reference surface. Images of reflected linearly polarized light wave for a plurality of wavelengths are obtained. The images are obtained for at least four polarizations for each of the plurality of wavelengths. The reflected linearly polarized light wave is a reflection of the linearly polarized light wave directed towards the object surface and the reference surface. The topography of the object surface based on the obtained images is obtained.

Abstract: Provided is a shape measurement system in order to perform three-dimensional measurement corresponding to a measurement object having various shapes, which includes a measurement probe, a probe tip unit, and a calculation unit. The probe tip unit includes an optical element that is configured to irradiate an object with measurement light, a fixing mechanism that is configured to fix to the measurement probe so as to be detachable and replaceable, and a cylindrical unit that is configured to lock the optical element and is provided with the fixing mechanism.

Abstract: The methods disclosed herein include recording at near-vertical first and second measurement positions respective first and second interferograms of the photomask surface and defining a difference map as the difference between the first and second interferograms. Respective first and second normal forces on the photomask are also measured at the first and second measurement positions. The change in the normal force is used define a scaling factor, which is applied to the difference map to define a scaled difference map. A compensated flatness measurement with a reduced shape contribution due to gravity is obtained by subtracting the scaled difference map from the first interferogram. An interferometer-based flatness measurement system is also disclosed.

Abstract: A system deposits a film on a substrate while determining mechanical stress experienced by the film. A substrate is provided in a deposition chamber. A support disposed in the chamber supports a circular portion of the substrate with a first surface of the substrate facing a deposition source and a second surface being reflective. An optical displacement sensor is positioned in the deposition chamber in a spaced-apart relationship with respect to a portion of the substrate's second surface located at approximately the center of the circular portion of the substrate. When the deposition source deposits a film on the first surface, a displacement of the substrate is measured using the optical displacement sensor. A processor is programmed to use the substrate displacement to determine a radius of curvature of the substrate, and to use the radius of curvature to determine mechanical stress experienced by the film during deposition.

Abstract: An optical system includes a polarized light phase shift optical circuit that includes a polarizing beam splitter that splits light having a coherence length shorter than a difference in optical path length between a normal optical path and a delay optical path having an optical path length longer than the normal optical path, the light being split into normal light, which travels along the normal optical path, and delay light, which travels along the delay optical path; a separator where the normal light and the delay light are individually emitted at a reference flat and the separator divides the reflected light that reflects off the reference flat into a plurality of light beams; and a plurality of image capture elements that respectively detect the intensities of the plurality of divided light beams, and the optical system also includes an information processor that includes a calibrator.

Abstract: Systems and methods that enable both spectroscopy and rapid chemical and/or optical imaging using a broadband light source. Broadband light sources may be advantageous for spectroscopy as they simultaneously illuminate a sample with a plurality of wavelengths and use interferometric techniques to determine a material response as a function of wavelength (or equivalently wavenumber). Some embodiments may enable the same radiation sources to be used to efficiently map the spatial distribution of chemical species or optical property variations. This may be achieved via selection of specific optical phase delays within an interferometer that are selected to maximize the contrast between different absorption bands or resonances within the sample. By optimally selecting specific interferometer phases it may be possible to construct images that substantially represent the material response to a specific wavelength excitation, without the necessity to obtain entire spectra at each sample location.

Abstract: A method performs phase shift interferometry to detect irregularities of a surface of a wafer after the wafer has been placed into an interferometer and while the wafer is vibrating. Additionally, a system and a non-transitory computer-readable storage medium have computer-executable instructions embodied thereon for performing phase shift interferometry to detect irregularities of a surface of a wafer after the wafer has been placed into an interferometer and while the wafer is vibrating.

Abstract: The present invention is directed to a system and method for on-line real-time measuring the surface topography and out-of-plane deformation by using phase-shifting shadow moiré method. Digital Phase-Shifting Shadow Moiré Method is applied to a system, which receives the reflected images from the surface of transparent or non-transparent plate projected under a light beam passing through a grating. Next, by image correction program, the skewed interference fringe pattern is recovered to the image as if the image acquisition equipment is placed normal to the surface. Furthermore, the received images are processed with Phase-Shifting to show the surface topography of the plate.

Abstract: A system and method for forming a semiconductor device is provided. The system may measure characteristics of the substrate to determine an amount of induced stress on the substrate. The measured characteristics may include warpage, reflectivity and/or crack information about the substrate. The induced stress may be determined, at least in part, based on the measured characteristics. The system may compare the induced stress on the substrate to a maximum intrinsic strength of the substrate and adjust an anneal for the substrate based on the comparison. The adjustment may reduce or limit breakage of the substrate during the anneal. The system may control at least one of a peak anneal temperature and a maximum anneal duration for an anneal unit, which may perform an anneal on the substrate. The measurements and control may be performed ex-situ or in-situ with the anneal.

Abstract: A method for absolute measurement of flatness of surfaces of optical elements. In the method, an interferometer having a measurement axis is used for applying a three-flat method to three optical elements, by conducting actual measurements on the elements, surfaces of the elements are reconstructed by an iterative processing operation in which measurements are simulated and simulated measurements are compared with the actual measurements. At least two actual measurements are made after having performed a rotation around the measurement axis and/or a translation perpendicular to the measured axis, of a measured optical element relative to the other.

Abstract: Apparatus and methods for detecting optical profile are disclosed herein. In one embodiment, an apparatus includes a laser, a beam splitter, a collimation optical unit, first and second holders respectively holding a first test flat mirror and a second test flat mirror, a phase shifter connected with the first holder, and an angular measurement unit for measuring an angular error of the first test flat mirror and the second test flat mirror on the two holders. The first test flat mirror has a first test flat and the second test flat mirror has a second test flat. The apparatus further includes a planar imaging unit for generating the interfered test light having a direction generally along an x-axis direction of the first test flat and an x-axis direction of the second test flat and a convergence optical unit for projecting the interfered test light onto a detector.

Abstract: The present invention provides a quality inspection method of a glass plate, which can predict the shape of the glass based on three types of design shape data C1, C2 and C3 of a glass plate in a state that it is placed on a three-point supporting type actual measurement inspection stand and an actual measurement shape data Y1 of the glass plate. The virtual errors ?C2=C2?C1, ?C3=C3?C1 and ?Y1=Y1?C1 at four supporting points of the glass plate are calculated, the correction amount R=r(C3?C1) or the correction amount R=r(C2?C1) is subtracted from Y1?C1 to calculate a value corresponding to a difference Y2?A between a shape data Y2 of the glass on a desired actual measurement inspection stand and a design data A on the desired actual measurement inspection stand, and from the value corresponding to a difference Y2?A and a quality standard, the quality of the glass plate is judged.

Abstract: A system for inspecting specimens such as semiconductor wafers is provided. The system provides scanning of dual-sided specimens using a diffraction grating that widens and passes nth order (n>0) wave fronts to the specimen surface and a reflective surface for each channel of the light beam. Two channels and two reflective surfaces are preferably employed, and the wavefronts are combined using a second diffraction grating and passed to a camera system having a desired aspect ratio. The system preferably comprises a damping arrangement which filters unwanted acoustic and seismic vibration, including an optics arrangement which scans a first portion of the specimen and a translation or rotation arrangement for translating or rotating the specimen to a position where the optics arrangement can scan the remaining portion(s) of the specimen. The system further includes-means for stitching scans together, providing for smaller and less expensive optical elements.

Abstract: The time delay (and therefore the OPD) between object and reference beams in an interferometer is manipulated by changing the spectral properties of the source. The spectral distribution is tuned to produce a modulation peak at a value of OPD equal to the optical distance between the object and reference arms of a Fizeau interferometer, thereby enabling the use of its common-axis configuration to carry out white-light measurements free of coherence noise. Unwanted interferences from other reflections in the optical path are also removed by illuminating the object with appropriate spectral characteristics. OPD scanning is implemented without mechanical means by altering the source spectrum over time so as to shift the peak location by a predetermined scanning step between acquisition frames. The invention and its advantages are applicable to optical coherence tomography as well as conventional white light interferometry.

Abstract: Described are a method and device for determining three-dimensional position information of a surface of a translucent object having a wavelength-dependent transmittance and reflectance characteristics. The method includes illuminating the surface of the translucent object with optical radiation at a predetermined wavelength emitted from a pair of optical sources. Radiation scattered from the surface and below the surface is detected, and a phase of the optical radiation from one of the optical sources relative to a phase of the optical radiation from the other optical source is changed before again detecting the scattered radiation. The predetermined wavelength is selected so that the optical radiation scattered from below the surface and detected provides a substantially constant background intensity with respect to the optical radiation scattered from the surface and detected. Three-dimensional position information of the surface is calculated in response to the detected radiation.

Abstract: An adaptive algorithm is tailored to fit the local fringe frequency of single-frame spatial-carrier data under analysis. Each set of data points used sequentially by the algorithm is first processed with a Fourier Transform to find the local frequency of the fringes being analyzed. That information is then used to adapt the algorithm to the correct phase step thus calculated, thereby optimizing the efficiency and precision with which the algorithm profiles the local surface area. As a result, defects are identified and measured with precision even when the slope of the surface varies locally to the point where the algorithm without adaptive modification would not be effective to measure them. Once so identified, the defects may be measured again locally with greater accuracy by conventional temporal PSI.

Abstract: Disclosed is a method that includes combining a first light beam and at least a second light beam to form a combined light beam, introducing a sinusoidal phase shift with a frequency f between a phase of the first light beam and a phase of the second light beam, recording at least one interference signal based on a modulation of the combined light beam in response to the sinusoidal phase shift, where the interference signal includes at least three different frequency components, and outputting the information. For each interference signal, information related to the difference in optical path lengths of the first and second light beam is determined by comparing the intensity of the at least three different frequency components of the interference signal.

Abstract: A method for inspecting a transparent substrate provides an index-matching fluid between an index-matched optical coupler and a surface of the transparent substrate. The method repeats, at two or more positions along the surface of the transparent substrate, steps of illuminating an inspection volume within the transparent substrate by directing a ribbon of light through the optical coupler and into the transparent substrate and detecting scattered light from the inspection volume at a detector that is optically conjugate with the inspection volume.

Abstract: A shape measuring method for measuring a surface shape of a measurement target includes dividing light from a light source into measurement light and reference light, the measurement light being obliquely incident upon a surface of the measurement target, the reference light being incident upon a reference mirror, introducing the measurement light reflected by the measurement target and the reference light reflected by the reference mirror to a photoelectric conversion element, detecting interference light formed by the measurement light and the reference light by the photoelectric conversion element while moving the measurement target, and measuring the surface shape of the measurement target based on an interference signal obtained from the measurement light that has been reflected at the same position on the surface of the measurement target.

Abstract: In general, in one aspect, the invention features an apparatus including a multi-axis interferometer configured to produce at least three output beams each including interferometric information about a distance between the interferometer and a measurement object along a corresponding measurement axis, wherein at least three of the measurement axes are in a common plane, wherein the output beams each include a component that makes a pass to the measurement object along a common beam path.

Abstract: A method of measuring a 3D shape includes the steps of measuring a brightness of a first illumination source 41a, measuring a phase-to-height conversion factor, measuring a 3D shape of a circuit board 62 according to the normal inspection mode, and determining whether bare board information about the circuit board 62 is included. If the information is not included, performing bare board teaching to acquire the information. Then, the 3D shape of target objects on the circuit board 62 are measured, when the bare board information is included or bare board teaching information is generated. Next, the circuit board 62 is analyzed to determine if it is normal or abnormal by using 3D shape information.

Abstract: A substrate inspection method includes: generating primary charged particle beams; applying the generated primary charged particle beams to an inspection target of a substrate; condensing first secondary charged particle beams including at least one of secondary charged particles, reflected charged particles, and back scattering charged particles which have been generated from the substrate, or first transmitted charged particle beams which have transmitted the inspection target, a phase difference being generated between the secondary charged particle beams or between the transmitted charged particle beams in accordance with a structure of the inspection target; imaging the secondary charged particle beams or the transmitted charged particle beams; detecting the imaged secondary charged particle beams or transmitted charged particle beams and outputting a signal of a secondary charged particle beam image or a transmitted charged particle beam image including information on the phase difference; and detecting

Abstract: In general, in one aspect, the invention features an apparatus that includes an interferometer having a main cavity and an auxiliary reference surface, the main cavity including a partially reflective surface defining a primary reference surface and a test surface. The interferometer is configured to direct a primary portion of input electromagnetic radiation to the main cavity and an auxiliary portion of the input electromagnetic radiation to reflect from the auxiliary reference surface, wherein a first portion of the primary portion in the main cavity reflects from the primary reference surface and a second portion of the primary portion in the main cavity passes through the primary reference surface and reflects from the test surface. The interferometer is further configured to direct the electromagnetic radiation reflected from the test surface, the primary reference surface, and the auxiliary reference surface to a multi-element detector to interfere with one another to form an interference pattern.

Abstract: An optical interferometer (100) includes a first optical interferometer (200) disposed on a front surface side of a workpiece (W) and a second optical interferometer (300) disposed on a rear surface side of the workpiece (W). The first optical interferometer (200) and the second optical interferometer (300) each include a light emitting section (210, 310), a wire grid (220, 320) and an interference fringe sensor (230, 330). Wire alignment directions of the wire grid (220) of the first optical interferometer (200) and the wire grid (320) of the second optical interferometer (300) are orthogonal to each other. When no workpiece (W) is set, the wire grid (220) of the first optical interferometer (200) reflects light from the second optical interferometer (300) to generate object light and the wire grid (320) of the second optical interferometer (300) reflects light from the first optical interferometer (200) to generate object light.

Abstract: A Fizeau or other interferometer is used to provide high resolution, in-situ calibration of an external angle measurement system such as widely spaced high stability plane mirror interferometers (HSPMIs)). The calibrated measurement system then measures mechanical tilt during shearing. The tilt data is used to correct the sheared data, preferably before computation of the rotationally invariant (RI) terms. Alternatively, the data may be used to compute the spurious quadratic term and correct after integration.

Abstract: A method of measuring the topography of a large, thin, non-flat specular substrate in a production environment with minimal movement of a majority of the measurement apparatus. A gimbal-mounted reflecting element is used to steer a short coherence length probe beam such that the probe beam is substantially perpendicular to a local surface of the substrate. The probe beam and the reference beam are combined and the resulting interference pattern used to characterize defects on the local surface.

Abstract: Apparatus and methods for generating an empirically determined mathematical model of wavefront error in an interferometer as a function of aperture misalignment and then applying the model to correct subsequent measurements. The methods are useful in Fizeau and other types of interferometers in which carrier fringe analysis may be used for reducing errors caused by environmental and vibration effects.

Abstract: A method for determining at least one of distortion and de-focus for an optical imaging system. The method includes determining wavefront aberrations in a pupil plane of the optical imaging system by a wavefront measurement method, determining focus offset measured values in an xy-direction and/or z-direction for one or more different illumination settings by a test pattern measurement method with imaging and comparative evaluation of test patterns for the optical imaging system, and determining values for one or more aberration parameters that relate to the distortion and/or image surface from a prescribed relationship between the determined wavefront aberrations and the determined focus offset measured values.

Abstract: An interferometer for measuring the flatness, variation of thickness and parallelism of large, thin transparent wafers held vertically and undistorted by gravitational forces. A sodium lamp provides monochromatic light that is diffusely reflected off a background screen towards the wafer. A reference flat surface is positioned sufficiently closely to the wafer that an interference fringe pattern is formed that is a measure of the air gap between the reference flat surface and the surface of the wafer being measured. The background screen is angled so that the fringe pattern, which is localized at the air gap can be viewed at an angle to a normal to the wafer. The background screen has trapezoidal markings that, when viewed at the angle required to see the fringes, appear as a grid. This allows counting of the number of fringes visible within a fixed distance to characterize the surface flatness.

Abstract: The light intensity ratio adjustment filter is placed between the reference surface and the sample surface of the interferometer. This light intensity ratio adjustment filter has a light intensity ratio adjustment film including an optical reflection-absorption layer and a dielectric anti-reflection layer on the surface of a transparent substrate made of glass on the sample side, and an optical anti-reflection film on the reference surface side, and acts so as to reflect part of the incident light from the surface opposite the reference surface, and after absorbing part of the remaining light, transmit the remainder towards the sample, and furthermore, absorb part of the light returned from the sample while controlling reflection, and transmit the remainder in the direction of the reference surface as the sample light.

Abstract: Techniques and systems for using optical interferometers to obtain full-field optical measurements of surfaces, such as surfaces of flat panels, patterned surfaces of wafers and substrates. Applications of various shearing interferometers for measuring surfaces are described.

Abstract: A surface texture measuring instrument provided with a near-field measuring unit (30) including a near-field probe (33) that forms a near-field light at a tip end thereof when a laser beam is irradiated, a laser source (35) that generates the laser beam to be irradiated on the near-field probe (33), a detection element (38) that detects scattering effect of the near-field light generated when the near-field probe (33) is moved close to a workpiece (1), and an actuator (32) that displaces the near-field probe (33) and the workpiece (1) in a direction moving close to/away from each other, includes: a laser length-measuring unit (20) that measures a relative distance between a reference position and the workpiece (1) in the vicinity of the tip end of the near-field probe (33) or a relative distance between the reference position and the near-field probe (33).

Abstract: A method of processing a substrate having an optical surface includes using an interferometer which includes optics for providing a beam of measuring light. The optics polarize the beam of measuring light such that a tangential polarization component continuously increases relative to a radial polarization component with increasing distance from an optical axis. The substrate is positioned in the beam of measuring light. Using the system, the interferometer determines a surface map of the optical surface, and determines deviations of the optical surface from a target shape.

Abstract: The present invention provides a form measuring device including a measuring section (302) for obtaining measurement data obtained by measuring a space between a straightedge rule (321) and an edge of an object to be measured (305) paired with each other, a function value setting section for setting form-function values, which indicates distances from a reference line R to the straightedge rule (321) and to edges of the object to be measured, and angle-function values ?, which indicates internal angles of the object to be measured 305 and an angle formed by the straightedge rules (321), a simultaneous equation deriving section for deriving simultaneous equations for pains each consisting of the straightedge rule (321) and an edge of the object to be measured (305) based on the measurement data, and a simultaneous equation processing section for processing the derived simultaneous equations.

Abstract: A system for inspecting specimens such as semiconductor wafers is provided. The system provides scanning of dual-sided specimens using a diffraction grating that widens and passes nth order (n>0) wave fronts to the specimen surface and a reflective surface for each channel of the light beam. Two channels and two reflective surfaces are preferably employed, and the wavefronts are combined using a second diffraction grating and passed to a camera system having a desired aspect ratio. The system preferably comprises a damping arrangement which filters unwanted acoustic and seismic vibration, including an optics arrangement which scans a first portion of the specimen and a translation or rotation arrangement for translating or rotating the specimen to a position where the optics arrangement can scan the remaining portion(s) of the specimen. The system further includes means for stitching scans together, providing for smaller and less expensive optical elements.

Abstract: A method of processing an optical element comprises providing an interferometer optics; arranging a calibrating substrate in a beam of measuring light emitted by the interferometer optics; superimposing measuring light having traversed the first and second surfaces of the calibrating substrate with reference light, and taking a first interferometric measurement of the superimposed measuring light and reference light; arranging the aspherical surface of the optical element in the beam of measuring light emitted by the interferometer optics, while the calibrating substrate is not arranged in the beam of measuring light; superimposing measuring light having interacted with the aspherical surface and the reference light, and taking a second interferometric measurement of the superimposed measuring light and reference light; determining deviations of the aspherical surface from a target shape thereof in dependence of the first and second measurements; and machining the aspherical surface of the optical element.

Abstract: A surface inspection apparatus for inspecting a surface of an object to be inspected, includes: a projecting optical system which projects an inspection light to the object surface via a reference surface; a pick up unit which picks up surface interference fringes formed by reflected light from the reference surface and reflected light from the object surface; and an arithmetic unit which calculates a shape of the surface of the object based on the picked up interference fringes. The projecting optical system includes a laser light source that emits, as the inspection light, pulsed laser light having a pulse width and a pulse quiescent time capable of preventing formation of rear face interference fringes which are formed by the reflected light from the object surface and reflected light caused by the inspection light being reflected from its rear face, the object allowing the inspection light to pass therethrough.

Abstract: An apparatus including: an interferometer comprising a series of three partially reflective reference surfaces, wherein the interferometer is configured to direct electromagnetic radiation to a test surface along a path through the series of three partially reflective reference surfaces, and direct the electromagnetic radiation reflected from each of the surfaces to form an optical interference pattern on a detector, wherein the interferometer comprises a first reference optic supporting the first reference surface and a second reference optic supporting the second and third reference surfaces, and wherein the second reference optic is configured to adjustably rotate to exchange an order of the second and third reference surfaces along the path relative to the first reference surface.

Abstract: An apparatus capable of measuring topography and transparent film thickness of a patterned metal-dielectric layer on a substrate without contact with the layer. A broadband interferometer measures an absolute phase of reflection at a plurality of wavelengths from a plurality of locations within a field of view on the metal-dielectric patterned layer on the substrate, and produces reflection phase data. An analyzer receives the reflection phase data and regresses the transparent film thickness and the topography at each of the plurality of locations from the reflection phase data. In this manner, the apparatus is not confused by the phase changes produced in the reflected light by the transparent layers, because the thickness of the transparent layers are determined by using the reflection phase data from multiple wavelengths. Further, the surface topography of the layer, whether it be opaque or transparent is also determinable.

Abstract: Systems and methods are described for rapid acquisition of fused off-axis illumination direct-to-digital holography. A method of recording a plurality of off-axis object illuminated spatially heterodyne holograms, each of the off-axis object illuminated spatially heterodyne holograms including spatially heterodyne fringes for Fourier analysis, includes digitally recording, with a first illumination source of an interferometer, a first off-axis object illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; and digitally recording, with a second illumination source of the interferometer, a second off-axis object illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis.

Abstract: An apparatus for measuring an object's surface shape that obtains complex amplitude at a plurality of positions substantially in the directions of the optical axis of the light reflected by the object and calculates the first surface shape of the object by the depth-from-focus principle. On the other hand, using the phase data of the complex amplitude, the apparatus can measure a micro shape in the sub-fringe order by ordinary laser interference measurement. The first surface shape data are applied to a region including a step of a height greater than ½ of the light's wavelength and second surface shape data are applied to the other region.

Abstract: A system and method are provided for obtaining mapping profiles of transparent objects having a plurality of reflective surfaces. The object, the surfaces of which are to be mapped, is placed in an unequal path interferometer including a reference surface located a predetermined distance from the object. Coherent light is supplied in the interferometer from a tunable source; and multiple optical interferograms for each of the plurality of reflective surfaces are simultaneously recorded. These interferograms are simultaneously extracted through the use of a dynamically generated weighted least-square fitting technique; which separates interferograms from a set of superimposed interferograms to obtain a given interferogram for any one of the surfaces, free from errors resulting from the existence of the other interferograms.

Abstract: The invention features methods and systems in which wavelength-tune PSI data is analyzed in the frequency domain to produce spectrally separated frequency peaks each corresponding to a particular pair of surfaces in an interferometric cavity defined by multiple pairs of surfaces. Each frequency peak provides optical path length information about a corresponding pair of surfaces in the cavity. As a result, the interferometric data from such cavities provides simultaneous information about multiple surfaces.

Abstract: The invention comprises methods and apparatus for reducing sub-harmonic cyclic errors by rotating by a small angle an interferometer or elements thereof. The rotation of the interferometer or selective elements thereof introduces a corresponding small angle between a sub-harmonic type spurious beam that subsequently interferes with either the reference or measurement beam so that the fringe contrast of the interference terms between the subharmonic spurious beam and either the reference or measurement beam is reduced by a required factor for a given use application thereby reducing nonlinearities in the phase signal.

Abstract: A system and method for in-line inspection of specimens such as semiconductor wafers is provided. The system provides scanning of sections of specimens having predetermined standardized characteristics using a diffraction grating that widens and passes nth order (n>0) wave fronts to the specimen surface and a reflective surface for the transmitted light beam. Light energy is transmitted in a narrow swath across the portion of the surface having the standardized features. The wavefronts are combined using a second diffraction grating and passed to a camera system having a desired aspect ratio.

Abstract: Interferometric method(s) and apparatus for accurately measuring aspherical surfaces and transmitted wavefronts, particularly of the type having relatively large diameters and departure employed in lithographic applications used in the fabrication of integrated circuits and the like. An interferometer, preferably of the Fizeau type, is provided with at least one aspherical reference surface that is positioned adjacent the test optic. The test optic can be either rotationally or non-rotationally symmetric, a reflecting aspherical test surface, or a refracting system that is illuminated by an aspherical wavefront or produces a transmitted aspherical wavefront. In any case, the departure of the test optic from its intended performance is ultimately determined. The aspherical reference surface is illuminated by an aspherical wavefront provided by upstream optics structured so that the incident aspherical wavefront propagates normal to the aspherical reference surface across its entire surface.

Abstract: A system and method are provided for obtaining mapping profiles of transparent objects having a plurality of reflective surfaces. The object, the surfaces of which are to be mapped, is placed in an unequal path interferometer including a reference surface located a predetermined distance from the object. Coherent light is supplied in the interferometer from a tunable source; and multiple optical interferograms for each of the plurality of reflective surfaces are simultaneously recorded. These interferograms are simultaneously extracted through the use of a dynamically generated weighted least-square fitting technique, which separates interferograms from a set of superimposed interferograms to obtain a given interferogram for any one of the surfaces, free from errors resulting from the existence of the other interferograms.

Abstract: A non-contact measurement apparatus and method. A probe is provided for mounting on a coordinate positioning apparatus, comprising at least one imaging device for capturing an image of an object to be measured. Also provided is an image analyzer configured to analyze at least one first image of an object obtained by the probe from a first perspective and at least one second image of the object obtained by the probe from a second perspective so as to identify at least one target feature on the object to be measured. The image analyzer is further configured to obtain topographical data regarding a surface of the object via analysis of an image, obtained by the probe, of the object on which an optical pattern is projected.