Abstract: An optical inspection system includes a polarizing isolator that reduces error in measurements by preventing ghost light reflected or scattered from element of a detection subsystem from re-entering the illumination and detection optical paths. The polarizing isolator may include a polarizing splitter that isolates light directionally according the a linear polarization state and two quarter-wave plates for transforming linearly polarized light to circularly polarized light.

Abstract: An optical inspection system includes a polarizing isolator that reduces error in measurements by preventing ghost light reflected or scattered from element of a detection subsystem from re-entering the illumination and detection optical paths. The polarizing isolator may include a polarizing splitter that isolates light directionally according the a linear polarization state and two quarter-wave plates for transforming linearly polarized light to circularly polarized light.

Abstract: An optical surface inspection system provides dark-field detection avoiding ghost images and without capturing, stray, reflected or re-scattered light. The system includes an illumination system that generates an illumination spot on a surface under inspection collecting lens that collects substantially all light scattered from the surface under inspection from the illumination spot. The system also includes a light guide with a first end having a numerical aperture matched to an exit aperture of the collecting lens and a field of view matched to the illumination spot, and a second end coupled to a detector.

Abstract: An optical measuring system includes a scatterometer in which an illumination beam is provided through an aperture in a lens used to collect light for the scattering detection. The void may be a slit in the lens, a missing portion along an edge of the lens, or another suitable void. Another detection channel may be provided to detect light returning through the void in the collecting lens, for example, a profilometer may be implemented by detecting interference between reflected light returning along the illumination path and light from the illumination source.

Abstract: An optical inspection system includes a fluorescence channel that detects fluorescent behavior (or lack thereof) of artifacts present on a surface under inspection and at least one other optical channel for determining a characteristic of the surface under inspection in an illuminated spot. The other optical channel may be a height measuring channel, such as an interferometric channel or a deflectometric channel, the other optical channel may be a scatterometric channel, or both height measurement and scatterometry may be employed in combination as a three channel system. The presence of absence of fluorescent behavior may be used to correct assumptions about or determine a type of artifact detected by scatterometry, and may be used to correct the polarity of a height measurement made by a height-measuring channel.

Abstract: Methods and apparatus, including computer program products, implementing and using techniques for collecting optical data pertaining to one or more characteristics of a sample. The apparatus has a light source, one or more illumination optical elements, a scanner, one or more collection optical elements, and a device forming an aperture that limits detection of light from the sample. The illumination optical elements direct a light beam from the light source onto the sample. The scanner scans the light beam across the sample. The collection optical elements collect light from the sample and transmit the collected light to a detector. None of the collection optical elements are included among the illumination optical elements. The device forming an aperture limits detection of light from the sample to light associated with a limited vertical depth within the sample, and is one of the collection optical elements.

Abstract: A scatterometer-interferometer and method for detecting and distinguishing characteristics of surface artifacts provides improved artifact detection and increased scanning speed in interferometric measurement systems. A scatterometer and interferometer are combined in a single measurement head and may have overlapping, concentric or separate measurement spots. Interferometric sampling of a surface under measurement may be initiated in response to detection of a surface artifact by the scatterometer, so that continuous scanning of the surface under measurement can be performed until further information about the size and/or height of the artifact is needed.

Abstract: Methods and apparatus, including computer program products, implementing and using techniques for collecting optical data pertaining to one or more characteristics of a sample. A light beam of a first frequency is scanned onto a sample surface using one or more illumination optical elements. Light of a second frequency is collected from a scan line on the sample surface using one or more collection optical elements. None of the one or more collection optical elements are included among the one or more illumination optical elements. The collected light is transmitted to a detector.

Abstract: A scatterometer-interferometer and method for detecting and distinguishing characteristics of surface artifacts provides improved artifact detection and increased scanning speed in interferometric measurement systems. A scatterometer and interferometer are combined in a single measurement head and may have overlapping, concentric or separate measurement spots. Interferometric sampling of a surface under measurement may be initiated in response to detection of a surface artifact by the scatterometer, so that continuous scanning of the surface under measurement can be performed until further information about the size and/or height of the artifact is needed.

Abstract: Methods and apparatus, including computer program products, implementing and using techniques for collecting optical data pertaining to one or more characteristics of a sample. The apparatus has a light source, one or more illumination optical elements, a scanner, one or more collection optical elements, and a device forming an aperture that limits detection of light from the sample. The illumination optical elements direct a light beam from the light source onto the sample. The scanner scans the light beam across the sample. The collection optical elements collect light from the sample and transmit the collected light to a detector. None of the collection optical elements are included among the illumination optical elements. The device forming an aperture limits detection of light from the sample to light associated with a limited vertical depth within the sample, and is one of the collection optical elements.

Abstract: A resonant ellipsometer and method for determining ellipsometric parameters of a surface provide an efficient and low-cost mechanism for performing ellipsometric measurements. A surface of interest is included as a reflection point of a resonance optical path within a resonator. The intersection of the resonance optical path with the surface of interest is at an angle away from normal so that the complex reflectivity of the surface alters the phase of the resonance optical path. Intensity measurements of light emitted from a partially reflective surface of the resonator for orthogonal polarizations and for at least two effective cavity lengths provide complete information for computing the ellipsoidal parameters on the surface of interest. The resonator may be a Fabry-Perot resonator or a ring resonator. The wavelength of the illumination can be swept, or the cavity length mechanically or electronically altered to change the cavity length.

Abstract: A Fabry-Perot resonator apparatus and method including an in-resonator polarizing element improves detection/measurement sensitivity of an optical system, provides both fields at a single end of the resonator, and overcomes other structural and performance limitations of particular optical systems. A polarizing element, which may be a quarter-wave plate, a 45-degree Faraday rotator or other polarizing element capable of converting between linear and circular polarizations and back, is placed in the resonance path of the Fabry-Perot resonator. The polarizing element effectively doubles the cavity length and orthogonally isolates forward from reverse reflection rays within the resonator, eliminating interference between rays and providing isolated bright and dark fields at each end of the resonator.

Abstract: Apparatus for sensing information regarding a surface including a first plurality of optical elements arranged to acquire two dimensional information about a surface, a second plurality of optical elements arranged to acquire topographical information about the surface, wherein the first plurality and the second plurality of optical elements are arranged to simultaneously provide the two dimensional information and the topographical information to at least partially non-overlapping portions of a single sensor array.

Abstract: A three-dimensional imaging resonator and method therefor provides improved surface height measurement capability in optical measuring systems. A resonator including a surface of interest in a resonant image path is coupled to an external multi-pixel detector that detects an image of intensity of light reflected from or transmitted through the resonator. An imaging system is included in the resonator to image a region of a surface of interest on another reflector forming part of the resonator. By changing an effective cavity length of the resonator, the image is “scanned” in a direction perpendicular to the other reflector and a processing system stores information corresponding to resonance peaks to achieve a mapping of feature height above the surface of interest. The resonator effective cavity length can be changed by sweeping the illumination wavelength or by mechanically or otherwise altering the optical length of the resonator.

Abstract: A resonator method and system for distinguishing characteristics of surface features or contaminants provides improved inspection or surface feature detection capability in scanning optical systems. A resonator including a surface of interest in the resonant path is coupled to a detector that detects light leaving the resonator. Changes in the resonance peak positions and peak intensities are evaluated against known changes for standard scatters in order to determine the material characteristics of an artifact at the surface of interest that causes a resonance change. The lateral size of the artifact is determined by de-convolving a known illumination spot size with the changing resonance characteristics, and the standard scatterer data is selected in conformity with the determined artifact size.

Abstract: A method and system for optical measurement via a resonator having a non-uniform phase profile provides a mechanism for measuring and/or detecting sub-micron surface features with increased resolution. A second surface forming part of a resonator is illuminated through a first partially reflective surface that has a non-uniform phase profile that transitions from negative to positive phase with respect to a resonance phase value of the resonator. As a result, a reduced spot size is produced at the second surface, which enhances the resolution of a measurement and/or detection of surface features on the second surface. Additionally, if a discontinuity is provided in the non-uniform phase profile, interaction of the discontinuity with surface features of the second surface will provide enhanced resolution of the surface features. The resolution of the system is improved over the resolution that can be attained using a Fabry-Perot resonator.

Abstract: An active sensor a method for optical illumination and detection provides low cost and high-speed optical scanning of bio-arrays, DNA samples/chips, semiconductors, micro-electromechanical systems and other samples requiring inspection or measurement. A plurality of illumination sources forming a parallel multi-pixel array is used to illuminate one or more samples via an imaging system or by placement in close proximity to the samples. The array may be a line array or a two-dimensional array. A plurality of detectors is integrated within the multi-pixel illumination array or provided in a separate array, each detector for detecting optical properties of the sample that results from illumination by one or more associated illumination sources. One detector may be associated with multiple illuminators or one illuminator may be associated with multiple detectors.

Abstract: A method and system for determining surface feature characteristics (including position and dimensions) using slit detectors provides a low-cost and high-speed measurement system for inspecting a surface. The system includes multiple slit detectors positioned so that a feature on a surface scanned by the system is detected by at least two detectors that are rotationally offset from each other and from the direction of scanning, a scanning control system for providing motion to the surface of interest in relation to the detectors, and an electronic analyzer for computing characteristics (including position and dimensions) of surface features.

Abstract: A method and apparatus including in-resonator imaging lens for improving resolution of a resonator-enhanced optical system provides resolution improvements for optical inspection and measurement systems, optical storage and retrieval systems as well as other optical systems. An imaging lens is incorporated in the resonator to image a point or area of one of the reflective surfaces of the resonator on a point or area of another reflective surface of the resonator. Resonance may be supported between the two surfaces, or with respect to only one surface with the other surface acting as an intermediary reflector. The partially reflective surface or a totally reflective surface may also be incorporated on a planar outside surface of the imaging lens.

Abstract: A three-dimensional imaging resonator and method therefor provides improved surface height measurement capability in optical measuring systems. A resonator including a surface of interest in a resonant image path is coupled to an external multi-pixel detector that detects an image of intensity of light reflected from or transmitted through the resonator. An imaging system is included in the resonator to image a region of a surface of interest on another reflector forming part of the resonator. By changing an effective cavity length of the resonator, the image is “scanned” in a direction perpendicular to the other reflector and a processing system stores information corresponding to resonance peaks to achieve a mapping of feature height above the surface of interest. The resonator effective cavity length can be changed by sweeping the illumination wavelength or by mechanically or otherwise altering the optical length of the resonator.