Abstract: The present disclosure is directed to a system for inspecting a sample with multiple wavelengths of illumination simultaneously via parallel imaging paths. The system may include at least a first detector or set of detectors configured to detect illumination reflected, scattered, or radiated along a first imaging path from a selected portion of the sample in response to the first wavelength of illumination and a second detector or set of detectors configured to concurrently detect illumination reflected, scattered, or radiated along a second imaging path from the selected portion of the sample (i.e. the same location on the sample) in response to the second wavelength of illumination, where the second imaging path may at least partially share illumination and/or detection optics with an autofocus channel.

Abstract: The present invention includes generating illumination, providing a spatial light modulator (SLM) configured to selectably illuminate one or more portions of a surface of a wafer using the generated illumination, receiving a sets of wafer pattern data indicative of one or more patterns of the wafer, translating the wafer along a direction, selectably controlling a pixel configuration of the SLM to control an illumination pattern on the surface of the wafer, a first pixel configuration illuminating a first set of regions of the wafer at an illumination level, an additional pixel configuration illuminating an additional set of regions at an additional illumination level, wherein a pixel pattern of the SLM based on the received sets of wafer pattern data is configured to move across a surface of the SLM synchronously with the pattern of the translated wafer, and detecting illumination from the surface of the wafer.

Abstract: The disclosure is directed to a system and method for inspecting a sample by illuminating the sample at a plurality of different angles and independently processing the resulting image streams. Illumination is directed through a plurality of pupil apertures to a plurality of respective field apertures so that the sample is imaged by portions of illumination directed at different angles. The corresponding portions of light reflected, scattered, or radiated from the surface of the sample are independently processed. Information associated with the independently processed portions of illumination is utilized to determine a location of at least one defect of the sample. Independently processing multiple image streams associated with different illumination angles allows for retention of frequency content that would otherwise be lost by averaging information from multiple imaging angles.

Abstract: The present disclosure is directed to a system for inspecting a sample with multiple wavelengths of illumination simultaneously via parallel imaging paths. The system may include at least a first detector or set of detectors configured to detect illumination reflected, scattered, or radiated along a first imaging path from a selected portion of the sample in response to the first wavelength of illumination and a second detector or set of detectors configured to concurrently detect illumination reflected, scattered, or radiated along a second imaging path from the selected portion of the sample (i.e. the same location on the sample) in response to the second wavelength of illumination, where the second imaging path may at least partially share illumination and/or detection optics with an autofocus channel.

Abstract: A system for inspecting a depth relative to a layer using a sensor with a fixed focal plane. A focus sensor senses the surface of the substrate and outputs focus data. In setup mode the controller scans a first portion of the substrate, receives the focus data and XY data, and stores correlated XYZ data for the substrate. In inspection mode the controller scans a second portion of the substrate, receives the focus data and XY data, and subtracts the stored Z data from the focus data to produce virtual data. The controller feeds the virtual data plus an offset to the motor for moving the substrate up and down during the inspection, thereby holding the focal plane at a desired Z distance.

Abstract: The disclosure is directed to a system and method for inspecting a sample by illuminating the sample at a plurality of different angles and independently processing the resulting image streams. Illumination is directed through a plurality of pupil apertures to a plurality of respective field apertures so that the sample is imaged by portions of illumination directed at different angles. The corresponding portions of light reflected, scattered, or radiated from the surface of the sample are independently processed. Information associated with the independently processed portions of illumination is utilized to determine a location of at least one defect of the sample. Independently processing multiple image streams associated with different illumination angles allows for retention of frequency content that would otherwise be lost by averaging information from multiple imaging angles.

Abstract: A system for inspecting a constant layer depth relative to a particular device layer. The system has an image sensor with a fixed focal plane. A focus sensor senses the surface topography of the substrate and outputs a focus data stream. A stage moves the substrate in an XY plane, and a motor moves the substrate in a Z dimension. A controller operates the system in one of a setup mode and an inspection mode. In the setup mode the controller controls XY movement of the substrate so as to scan a first portion of the substrate. The controller receives the focus data stream, concurrently receives XY data, and stores correlated XYZ data for the substrate. In the inspection mode the controller controls XY movement of the substrate so as to scan a second portion of the substrate. The controller receives the focus data stream, concurrently receives XY data, and subtracts the stored Z data from the focus data stream to produce a virtual data stream.

Abstract: A surface inspection apparatus in accordance with the principles of the invention includes an optical system having a plurality of time delay integration (TDI) sensors. The plurality of TDI sensors are arranged to generate a plurality of images of an object so that the images are offset a sub-pixel distance from each other. A scanning element enables the TDI sensors to scan the object so successive images of the object can be generated. Image processing circuitry is used to process the plurality of successive images together to produce a reconstructed image of the object having increased pixel density. The embodiments of the invention also include methods for generating reconstructed images from a plurality of TDI images obtained from at least two offset TDI sensors.

Abstract: A surface inspection apparatus in accordance with the principles of the invention includes an optical system having a plurality of time delay integration (TDI) sensors. The plurality of TDI sensors are arranged to generate a plurality of images of an object so that the images are offset a sub-pixel distance from each other. A scanning element enables the TDI sensors to scan the object so successive images of the object can be generated. Image processing circuitry is used to process the plurality of successive images together to produce a reconstructed image of the object having increased pixel density. The embodiments of the invention also include methods for generating reconstructed images from a plurality of TDI images obtained from at least two offset TDI sensors.

Abstract: A proximity effect correction method for electron beam lithography suitable for use in a raster scan system. The exposure pattern consists of shapes; these shapes are subdivided into edge pixels and interior pixels; the pattern is then modified by uniformly removing a fraction of the interior pixels. The method reduces the backscattered electron background dose, improving the contrast for shapes with fine features, particularly when they are in close proximity to large or densely packed shapes.

Abstract: A method and an apparatus detect in a light pattern the presence of defects (10') in a photomask (10) to which the light pattern corresponds. An inspection area (36) that includes the light pattern is partitioned into stripe regions (72). The width (70) of a stripe region corresponds to the maximum extent of the image window (54) of a charge-coupled camera device (42) that is employed to scan continuously each stripe region at a nominally constant speed. Each stripe region is divided into a first array (90) of pixel elements (92) arranged in rows (94) and columns (96). The camera device comprises plural light detecting elements (84) that are arranged in a second array (82) of rows (86) and columns (88). The camera continuously traverses the columns of the first array in a direction along the length of the stripe region and acquires in row-by-row fashion quantities of charge which correspond to the intensities of the light present in the pixel elements with which the light detecting elements are aligned.

Abstract: An inspection system (10, 100) employs a Fourier transform lens (34, 120) and an inverse Fourier transform lens (54, 142) positioned along an optic axis (48, 144) to produce from an illuminated area of a patterned specimen wafer (12) a spatial frequency spectrum whose frequency components can be selectively filtered to produce an image pattern of defects in the illuminated area of the wafer. Depending on the optical component configuration of the inspection system, the filtering can be accomplished by a spatial filter of either the transmissive (50) or reflective (102) type. The lenses collect light diffracted by a wafer die (14) aligned with the optic axis and light diffracted by other wafer dies proximately located to such die. The inspection system is useful for inspecting only dies having many redundant circuit patterns.

Abstract: A specimen distance measuring system uses a plate (36) to obstruct the flux of backscattered electrons produced by an electron beam (18), and to cast a shadow across a measurement detector (32) which is sensitive to the position of the shadow. The shadow plate (36) and measurement detector (32) are aligned at an angle of approximately 45 degrees with a substrate (14) in order to allow calibration of the distance measuring system by scanning the electron beam (18). The measuring system is particularly useful as a height sensor (10) in an electron beam lithography apparatus (12) for sensing the height of a substrate (14). The distance measuring system may also include a reference detector (34) which is positioned in order to receive backscattered electron flux without obstruction from the shadow plate (36).

Abstract: A translatable and rotatable mechanism is employed in optical processing apparatus for exposing a specimen pattern and inspecting light pattern or image developed from it. The mounting mechanism includes a plate that is rotatably mounted on a linear positioning table assembly. The plate includes a substrate arm and a camera arm that extend in opposite directions from the axis of rotation of the plate. The specimen pattern, such as a photomask, is positioned on the free end of the substrate arm, and a video camera is positioned on the free end of the camera arm. Whenever the plate is rotated to an exposure orientation, the photomask diffracts light rays emanating from a laser. The diffracted light rays interfere with a reference beam to form a hologram. Whenever the plate is rotated 180.degree. to an inspection orientation, a reconstructed imate of the photomask appears at the location where the photomask was positioned during exposure.

Abstract: An inspection system (10, 100) employs a Fourier transform lens (34, 120) and an inverse Fourier transform lens (54, 142) positioned along an optic axis (48, 144) to produce from an illuminated area of a patterned specimen wafer (12) a spatial frequency spectrum whose frequency components can be selectively filtered to produce an image pattern of defects in the illuminated area of the wafer. Depending on the optical component configuration of the inspection system, the filtering can be accomplished by a spatial filter of either the transmissive (50) or reflective (102) type. The lenses collect light diffracted by a wafer die (14) aligned with the optic axis and light diffracted by other wafer dies proximately located to such die. The inspection system is useful for inspecting only dies having many redundant circuit patterns.