Abstract: An optical system for controlling polarization may include an illumination source to illuminate a surface of a sample, a set of collection optics to collect illumination from the surface of a sample, and a wave plate having a spatially-varying surface profile along a thickness direction positioned at a pupil plane of the set of collection optics, where the spatially-varying surface profile of the wave plate is configured to control polarization rotation as a continuous function of transverse position, and where the spatially-varying surface profile is selected to rotate light scattered from a surface of a sample to a selected polarization angle. The system may further include a linear polarizer oriented to block light with the selected polarization angle, and a sensor to detect illumination transmitted through the linear polarizer.

Abstract: A system is disclosed. The system includes a stage assembly configured to receive a specimen and maintain a height of the specimen at a first working distance height during a first characterization mode and an additional working distance height during an additional characterization mode. The system further includes an illumination source configured to generate an illumination beam. The system further includes an illumination arm including a set of optical elements configured to direct a portion of the illumination beam including illumination of a first wavelength to the specimen during the first characterization mode, and direct a portion of the illumination beam including illumination of an additional wavelength to the specimen during the additional characterization mode. The system further includes a detector assembly configured to receive illumination emanated from the specimen, and a controller configured to determine a specimen height value based on the illumination received by the detector assembly.

Abstract: An optical system for controlling polarization may include an illumination source to illuminate a surface of a sample, a set of collection optics to collect illumination from the surface of a sample, and a wave plate having a spatially-varying surface profile along a thickness direction positioned at a pupil plane of the set of collection optics, where the spatially-varying surface profile of the wave plate is configured to control polarization rotation as a continuous function of transverse position, and where the spatially-varying surface profile is selected to rotate light scattered from a surface of a sample to a selected polarization angle. The system may further include a linear polarizer oriented to block light with the selected polarization angle, and a sensor to detect illumination transmitted through the linear polarizer.

Abstract: A polarization control device includes a first wave plate having a first surface profile and a second wave plate having a second surface profile complementary to the first surface profile. The optical axis of the first wave plate is orthogonal to the optical axis of the second wave plate. The first wave plate and the second wave plate are positioned to align the first surface profile with the second surface profile and maintain a constant thickness across the polarization control device. The first wave plate and the second wave plate may control polarization rotation as a continuous function of transverse position across a pupil plane of an optical system. The first wave plate and the second wave plate are separated by a sufficiently small distance so as to limit wave front distortion below a selected level.

Abstract: Stray and air scattered light can be reduced by configuring a size of the collection area of a sensor, which reduces a source of sensitivity-limiting noise in the system. By adjusting a size of the collection area, stray deep ultraviolet light and air-scattered deep ultraviolet light can be reduced. A servo can control a position of an illumination spot that is collected by the time delay and integration sensor.

Abstract: The inspection system includes an illumination source, a TDI-CCD sensor, and a dark field/bright field sensor. A polarizer receives the light from the light source. The light from the polarizer is directed at a Wollaston prism, such as through a half wave plate. Use of the TDI-CCD sensor and the dark field/bright field sensor provide high spatial resolution, high defect detection sensitivity and signal-to-noise ratio, and fast inspection speed.

Abstract: A system is disclosed. The system includes a stage assembly configured to receive a specimen and maintain a height of the specimen at a first working distance height during a first characterization mode and an additional working distance height during an additional characterization mode. The system further includes an illumination source configured to generate an illumination beam. The system further includes an illumination arm including a set of optical elements configured to direct a portion of the illumination beam including illumination of a first wavelength to the specimen during the first characterization mode, and direct a portion of the illumination beam including illumination of an additional wavelength to the specimen during the additional characterization mode. The system further includes a detector assembly configured to receive illumination emanated from the specimen, and a controller configured to determine a specimen height value based on the illumination received by the detector assembly.

Abstract: Stray and air scattered light can be reduced by configuring a size of the collection area of a sensor, which reduces a source of sensitivity-limiting noise in the system. By adjusting a size of the collection area, stray deep ultraviolet light and air-scattered deep ultraviolet light can be reduced. A servo can control a position of an illumination spot that is collected by the time delay and integration sensor.

Abstract: A polarization control device includes a first wave plate having a first surface profile and a second wave plate having a second surface profile complementary to the first surface profile. The optical axis of the first wave plate is orthogonal to the optical axis of the second wave plate. The first wave plate and the second wave plate are positioned to align the first surface profile with the second surface profile and maintain a constant thickness across the polarization control device. The first wave plate and the second wave plate may control polarization rotation as a continuous function of transverse position across a pupil plane of an optical system. The first wave plate and the second wave plate are separated by a sufficiently small distance so as to limit wave front distortion below a selected level.

Abstract: A polarization control device includes a first wave plate having a first surface profile and a second wave plate having a second surface profile complementary to the first surface profile. The optical axis of the first wave plate is orthogonal to the optical axis of the second wave plate. The first wave plate and the second wave plate are positioned to align the first surface profile with the second surface profile and maintain a constant thickness across the polarization control device. The first wave plate and the second wave plate may control polarization rotation as a continuous function of transverse position across a pupil plane of an optical system. The first wave plate and the second wave plate are separated by a sufficiently small distance so as to limit wave front distortion below a selected level.

Abstract: A luminescent tag based defect detection system comprises a luminescent tag attachment assembly, an illumination source, one or more detectors, and a set of optical elements. The luminescent tag attachment assembly exposes a sample to one or more luminescent tag materials selectively attached to one or more defects on the sample. The illumination source generates illumination including one or more wavelengths corresponding to the one or more absorption spectra associated with the one or more luminescent tags. At least a portion of the set of optical elements directs illumination from the illumination source to the sample, and at least a portion of the set of optical elements directs illumination emitted from the one or more luminescent tag materials to the one or more detectors. A luminescent tag based defect detection system may also include a luminescent tag removal assembly to remove the luminescent tags after detection.

Abstract: A wafer scanning system includes imaging collection optics to reduce the effective spot size. Smaller spot size decreases the number of photons scattered by the surface proportionally to the area of the spot. Air scatter is also reduced. TDI is used to produce a wafer image based on a plurality of image signals integrated over the direction of linear motion of the wafer. An illumination system floods the wafer with light, and the task of creating the spot is allocated to the imaging collection optics.

Abstract: Improvement of wafer surface inspection sensitivity includes acquiring a first inspection image from the surface of the wafer, generating a reference image by applying a thresholding function to the first image in order to isolate a speckle signal component of the first image induced by wafer surface roughness, acquiring one or more measurement inspection images from the surface of the wafer, and generating a difference image by subtracting the generated one or more reference images from the acquired one or more measurement inspection images.

Abstract: An inspection apparatus for simultaneous dark field (DF) and differential interference contrast (DIC) inspection includes an illumination source and a sample stage configured to secure a sample. The inspection apparatus includes a first sensor, a second sensor and an optical sub-system. The optical sub-system includes an objective, one or more optical elements arranged to direct, through the objective, illumination from the one or more illumination sources to a surface of the sample. The objective is configured to collect a signal from the surface of the sample, wherein the collected signal includes a scattering-based signal and/or a phase-based signal from the sample. The inspection apparatus includes one or more separation optical elements arranged to spatially separate the collected signal into a DF signal and a DIC signal by directing the DF signal and the DIC signal along a DF path and DIC path respectively.

Abstract: A wafer scanning system includes imaging collection optics to reduce the effective spot size. Smaller spot size decreases the number of photons scattered by the surface proportionally to the area of the spot. Air scatter is also reduced. TDI is used to produce a wafer image based on a plurality of image signals integrated over the direction of linear motion of the wafer. An illumination system floods the wafer with light, and the task of creating the spot is allocated to the imaging collection optics.

Abstract: An inspection apparatus for simultaneous dark field (DF) and differential interference contrast (DIC) inspection includes an illumination source and a sample stage configured to secure a sample. The inspection apparatus includes a first sensor, a second sensor and an optical sub-system. The optical sub-system includes an objective, one or more optical elements arranged to direct, through the objective, illumination from the one or more illumination sources to a surface of the sample. The objective is configured to collect a signal from the surface of the sample, wherein the collected signal includes a scattering-based signal and/or a phase-based signal from the sample. The inspection apparatus includes one or more separation optical elements arranged to spatially separate the collected signal into a DF signal and a DIC signal by directing the DF signal and the DIC signal along a DF path and DIC path respectively.

Abstract: Improvement of wafer surface inspection sensitivity includes acquiring a first inspection image from the surface of the wafer, generating a reference image by applying a thresholding function to the first image in order to isolate a speckle signal component of the first image induced by wafer surface roughness, acquiring one or more measurement inspection images from the surface of the wafer, and generating a difference image by subtracting the generated one or more reference images from the acquired one or more measurement inspection images.

Abstract: A polarization control device includes a first wave plate having a first surface profile and a second wave plate having a second surface profile complimentary to the first surface profile. The optical axis of the first wave plate is orthogonal to the optical axis of the second wave plate. The first wave plate and the second wave plate are positioned to align the first surface profile with the second surface profile and maintain a constant thickness across the polarization control device. The first wave plate and the second wave plate may control polarization rotation as a continuous function of transverse position across a pupil plane of an optical system. The first wave plate and the second wave plate are separated by a sufficiently small distance so as to limit wave front distortion below a selected level.