Abstract:
A inspection system includes an illumination source to generate an illumination beam, focusing elements to direct the illumination beam to a sample, a detector, collection elements configured to direct radiation emanating from the sample to the detector, a detection mode control device to image the sample in two or more detection modes such that the detector generates two or more collection signals based on the two or more detection modes, and a controller. Radiation emanating from the sample includes at least radiation specularly reflected by the sample and radiation scattered by the sample. The controller determines defect scattering characteristics associated with radiation scattered by defects on the sample based on the two or more collection signals. The controller also classifies the one or more particles according to a set of predetermined defect classifications based on the one or more defect scattering characteristics.
Abstract:
Disclosed are apparatus and methods for determining height of a semiconductor structure. The system includes an illumination module for directing one or more source lines or points towards a specimen having multiple surfaces at different relative heights and a collection module for detecting light reflected from the surfaces. The collection module contains at least two detectors with one slit or pinhole in front of each detector that that are positioned to receive light reflected from one of the surfaces. A first detector receives reflected light from a slit or pinhole that is positioned before a focal point, and a second detector receive reflected light from a slit or pinhole that is positioned after the focal point so that the first and second detector receive light having different intensity values unless the surface is at an optimum focus. The system includes a processor system for determining a height based on the detected light received by the detectors from two of the surfaces.
Abstract:
Disclosed are methods and apparatus for detecting defects in a semiconductor sample. The system includes an illumination optics module for simultaneously scanning two or more structured illumination (SI) patterns across the sample in a scan direction. The SI patterns have a phase shift with respect to each other, and the SI patterns are parallel to the scan direction. The system also includes a collection optics module for collecting output light from the sample in response to the SI patterns that are scanned across the sample and two or more detectors for individually detecting the output light collected for individual ones of the SI patterns. The system includes a controller to generate two or more SI images for the SI patterns based on the individually detected output light and detect defects on the sample by performing a comparison type inspection process based on the two or more SI images.
Abstract:
Systems and methods for inspecting a wafer are provided. One system includes an illumination subsystem configured to illuminate the wafer; a collection subsystem configured to collect light scattered from the wafer and to preserve the polarization of the scattered light; an optical element configured to separate the scattered light collected in different segments of the collection numerical aperture of the collection subsystem, where the optical element is positioned at a Fourier plane or a conjugate of the Fourier plane of the collection subsystem; a polarizing element configured to separate the scattered light in one of the different segments into different portions of the scattered light based on polarization; and a detector configured to detect one of the different portions of the scattered light and to generate output responsive to the detected light, which is used to detect defects on the wafer.
Abstract:
Illumination subsystems for multi-spot wafer inspection are provided. One illumination subsystem includes a diffractive optical element configured to separate an illumination light beam into multiple light beams and a refractive lens array positioned in the path of the multiple light beams. The refractive lens array is configured to relay the laser beam waist at the diffractive optical element onto a wafer surface and to separately and simultaneously focus each of the multiple light beams to a wafer for inspection.
Abstract:
A system which may be used to generate a plurality of spots on a surface is provided. The spots may be aligned with the incident plane of oblique illumination. The system may include a diffractive optical element configured to split a beam into a plurality of beams by generating a plurality of diffraction orders. The system may also include a focusing lens configured to focus at least some of the plurality of beams on the surface in the plurality of spots. At least some of the plurality of beams may be focused on the surface at an oblique illumination angle. The system may also include an illumination source positioned off-axis relative to an optical axis of the diffractive optical element. Using the system, a plurality of spots may be generated on an inclined surface.
Abstract:
Methods and systems for enhancing the dynamic range of a high sensitivity inspection system are presented. The dynamic range of a high sensitivity inspection system is increased by directing a portion of the light collected from each pixel of the wafer inspection area toward an array of avalanche photodiodes (APDs) operating in Geiger mode and directing another portion of the light collected from each pixel of the wafer inspection area toward another array of photodetectors having a larger range. The array of APDs operating in Geiger mode is useful for inspection of surfaces that generate extremely low photon counts, while other photodetectors are useful for inspection of larger defects that generate larger numbers of scattered photons. In some embodiments, the detected optical field is split between two different detectors. In some other embodiments, a single detector includes both APDs operating in Geiger mode and other photodetectors having a larger range.
Abstract:
This system comprises an illumination optics subsystem for generating and directing an incident beam towards a defect on a surface of a wafer. The illumination optics subsystem includes a light source for generating the incident beam and one or more polarization components for adjusting a ratio and/or a phase difference for the incident beam's electric field components. The system includes a collection optics subsystem for collecting scattered light from the defect and/or surface in response to the incident beam, and the collection optics subsystem comprises an adjustable aperture at the pupil plane, a rotatable waveplate for adjusting a phase difference of electric field components of the collected scattered light, and a rotatable analyzer. The system includes a controller for selecting a polarization of the incident beam, obtaining a defect scattering map from the defect, obtaining a surface scattering map from the background surface, and determining a configuration of the polarization components, aperture mask, rotatable waveplate, and analyzer based on analysis of the defect and surface scattering map to maximize a defect signal to noise ratio.
Abstract:
A inspection system includes an illumination source to generate an illumination beam, focusing elements to direct the illumination beam to a sample, a detector, collection elements configured to direct radiation emanating from the sample to the detector, a detection mode control device to image the sample in two or more detection modes such that the detector generates two or more collection signals based on the two or more detection modes, and a controller. Radiation emanating from the sample includes at least radiation specularly reflected by the sample and radiation scattered by the sample. The controller determines defect scattering characteristics associated with radiation scattered by defects on the sample based on the two or more collection signals. The controller also classifies the one or more particles according to a set of predetermined defect classifications based on the one or more defect scattering characteristics.
Abstract:
Disclosed is apparatus for inspecting a sample. The apparatus includes illumination optics for simultaneously directing a plurality of incident beams at a plurality of azimuth angles towards a sample and collection optics for directing a plurality of field portions of output light from two or more of the plurality of angles towards two or more corresponding sensors. The two or more sensors are arranged for receiving the field portions corresponding to two or more angles and generating two or more corresponding images. The apparatus further comprises a processor for analyzing the two or more images to detect defects on the sample