Abstract: An optical inspection system includes one or more gratings to convert the polarization of light scattered from a target from an elliptical polarization that varies spatially across a collection pupil to a linear polarization that is uniformly oriented across the collection pupil. The one or more gratings have phase retardation that varies spatially across the collection pupil in accordance with the elliptical polarization. The one or more gratings include at least one grating on a reflective substrate. The optical inspection system also includes a linear polarizer to filter out the linearly polarized light.

Abstract: A dark-field optical system may include a rotational objective lens assembly with a dark-field objective lens to collect light from a sample within a collection numerical aperture, where the dark-field objective lens includes an entrance aperture and an exit aperture at symmetrically-opposed azimuth angles with respect to an optical axis, a rotational bearing to allow rotation of at least a part of the dark-field objective lens including the entrance aperture and the exit aperture around the optical axis, and a rotational driver to control a rotational angle of the entrance aperture. The system may also include a multi-angle illumination sub-system to illuminate the sample with an illumination beam through the entrance aperture at two or more illumination azimuth angles, where an azimuth angle of the illumination beam on the sample is selectable by rotating the objective lens to any of the two or more illumination azimuth angles.

Abstract: An optical inspection system includes one or more single-material gratings to convert the polarization of light scattered from a target from an elliptical polarization that varies spatially across a collection pupil to a linear polarization that is uniformly oriented across the collection pupil. The one or more single-material gratings have phase retardation that varies spatially across the collection pupil in accordance with the elliptical polarization. The optical inspection system also includes a linear polarizer to filter out the linearly polarized light.

Abstract: An optical inspection system includes one or more gratings to convert the polarization of light scattered from a target from an elliptical polarization that varies spatially across a collection pupil to a linear polarization that is uniformly oriented across the collection pupil. The one or more gratings have phase retardation that varies spatially across the collection pupil in accordance with the elliptical polarization. The one or more gratings include at least one grating on a reflective substrate. The optical inspection system also includes a linear polarizer to filter out the linearly polarized light.

Abstract: A defect detection system includes a programmable and reconfigurable digital micro-mirror device (DMD) and at least one optical element. The DMD includes a micro-mirror array with a plurality of micro-mirrors adjustable to achieve a first deflection state or a second deflection state. The DMD is configured to receive incoming light and reflect a first portion of the incoming light into a first light channel corresponding to the first deflection state and a second portion of the incoming light into a second light channel corresponding to the second deflection state. The at least one optical element is optically coupled to the first light channel and the second light channel. The at least one optical element is configured to deflect the first portion of the incoming light to a first imaging lens and a second portion of the incoming light to a second imaging lens.

Abstract: A defect detection system includes a programmable and reconfigurable digital micro-mirror device (DMD) and at least one optical element. The DMD includes a micro-mirror array with a plurality of micro-mirrors adjustable to achieve a first deflection state or a second deflection state. The DMD is configured to receive incoming light and reflect a first portion of the incoming light into a first light channel corresponding to the first deflection state and a second portion of the incoming light into a second light channel corresponding to the second deflection state. The at least one optical element is optically coupled to the first light channel and the second light channel. The at least one optical element is configured to deflect the first portion of the incoming light to a first imaging lens and a second portion of the incoming light to a second imaging lens.

Abstract: Systems, methods, and apparatuses are disclosed herein for directing, using an optical arrangement including one or more lenses, a main beam and a leading beam toward a specimen such that the main beam is incident on the specimen at a main beam incidence and the leading beam is incident on the specimen at a leading beam incidence. The main beam intensity is greater than a leading beam intensity of the leading beam. A TDI sensor receives electromagnetic radiation from the leading beam incidence, thereby generating a first accumulated charge portion, and receives electromagnetic radiation from the main beam incidence, thereby generating a second accumulated charge portion. A processor maps the first accumulated charge portion to a first FOV, thereby yielding leading beam data, and maps the second accumulated charge portion to a second FOV, thereby yielding main beam data.

Abstract: A dark-field optical system may include a rotational objective lens assembly with a dark-field objective lens to collect light from a sample within a collection numerical aperture, where the dark-field objective lens includes an entrance aperture and an exit aperture at symmetrically-opposed azimuth angles with respect to an optical axis, a rotational bearing to allow rotation of at least a part of the dark-field objective lens including the entrance aperture and the exit aperture around the optical axis, and a rotational driver to control a rotational angle of the entrance aperture. The system may also include a multi-angle illumination sub-system to illuminate the sample with an illumination beam through the entrance aperture at two or more illumination azimuth angles, where an azimuth angle of the illumination beam on the sample is selectable by rotating the objective lens to any of the two or more illumination azimuth angles.

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: Methods and systems for reducing illumination intensity while scanning over large particles are presented herein. A surface inspection system determines the presence of a large particle in the inspection path of a primary measurement spot using a separate leading measurement spot. The inspection system reduces the incident illumination power while the large particle is within the primary measurement spot. The primary measurement spot and the leading measurement spot are separately imaged by a common imaging collection objective onto one or more detectors. The imaging based collection design spatially separates the image of the leading measurement spot from the image of the primary measurement spot at one or more wafer image planes. Light detected from the leading measurement spot is analyzed to determine a reduced power time interval when the optical power of the primary illumination beam and the leading illumination beam are reduced.

Abstract: A method and apparatus for producing high frequency dynamically focused oblique laser illumination for a spinning wafer inspection system. The focus is changed by changing the beam direction incidence angle so as to bring focal spot onto the wafer surface. Disclosed herein is a system and method for automatic beam shaping (i.e., spot size) and steering (i.e., position) for a spinning wafer inspection system, combined into a single module. Also disclosed is a method and system for measuring the beam position/size/shape and angle with sufficient resolution to make corrections using feedback from the monitor.

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: Methods and systems for reducing illumination intensity while scanning over large particles are presented herein. A surface inspection system determines the presence of a large particle in the inspection path of a primary measurement spot using a separate leading measurement spot. The inspection system reduces the incident illumination power while the large particle is within the primary measurement spot. The primary measurement spot and the leading measurement spot are separately imaged by a common imaging collection objective onto one or more detectors. The imaging based collection design spatially separates the image of the leading measurement spot from the image of the primary measurement spot at one or more wafer image planes. Light detected from the leading measurement spot is analyzed to determine a reduced power time interval when the optical power of the primary illumination beam and the leading illumination beam are reduced.

Abstract: A method and system for providing illumination is disclosed. The method may include providing a laser having a predetermined wavelength; performing at least one of: beam splitting or beam scanning prior to a frequency conversion; converting a frequency of each output beam of the at least one of: beam splitting or beam scanning; and providing the frequency converted output beam for illumination.

Abstract: A beam splitter includes first and second prisms. The first prism includes first, second, and third optical surfaces. The second prism includes three surfaces, one of which faces the second surface of the first prism and both transmit and reflect light. The first surface of the first prism is curved and forms a lens for focusing light either transmitted or reflected by the common interface between the two prisms. The first prism is from a single piece of material. Fabrication includes making two cuts through a lens to cut-out an intermediate section. A portion of the intermediate section is cut-off to form the third surface of the first prism. The first surface of the first prism corresponds to the curved top surface of the lens. The second surface of the first prism corresponds to the bottom plano surface of the lens. The first and second prisms are then combined.

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: A method and apparatus for producing high frequency dynamically focused oblique laser illumination for a spinning wafer inspection system. The focus is changed by changing the beam direction incidence angle so as to bring focal spot onto the wafer surface. Disclosed herein is a system and method for automatic beam shaping (i.e., spot size) and steering (i.e., position) for a spinning wafer inspection system, combined into a single module. Also disclosed is a method and system for measuring the beam position/size/shape and angle with sufficient resolution to make corrections using feedback from the monitor.

Abstract: The disclosure is directed to a system and method for inspecting a spinning sample by substantially simultaneously scanning multiple spots on a surface of the sample utilizing a plurality of illumination beams. Portions of illumination reflected, scattered, or radiated from respective spots on the surface of the sample are collected by at least one detector array. Information associated with at least one defect of the sample is determined by at least one computing system in communication with the detector array. According to various embodiments, at least one of scan pitch, spot size, spot separation, and spin rate is controlled to compensate pitch error due to tangential spot separation.

Abstract: A method and apparatus for producing high frequency dynamically focused oblique laser illumination for a spinning wafer inspection system. The focus is changed by changing the beam direction incidence angle so as to bring focal spot onto the wafer surface. Disclosed herein is a system and method for automatic beam shaping (i.e., spot size) and steering (i.e., position) for a spinning wafer inspection system, combined into a single module. Also disclosed is a method and system for measuring the beam position/size/shape and angle with sufficient resolution to make corrections using feedback from the monitor.

Abstract: Methods, systems, and structures for monitoring incident beam position in a wafer inspection system are provided. One structure includes a feature formed in a chuck configured to support a wafer during inspection by the wafer inspection system. The chuck rotates the wafer in a theta direction and simultaneously translates the wafer in a radial direction during the inspection. An axis through the center of the feature is aligned with a radius of the chuck such that a position of the axis relative to an incident beam of the wafer inspection system indicates changes in the incident beam position in the theta direction.