Abstract: The system includes a stage configured to support a workpiece and a plurality of optical heads arranged above the stage. Each optical head includes a camera configured to capture a first image of one of a plurality of targets defined on a surface of the workpiece positioned along an optical axis of the camera and a motion mechanism configured to translate the optical head along three axes relative to the stage and rotate the optical head along two axes orthogonal to the optical axis. For each optical head, a processor determines a corrective movement of the optical head based on a misalignment of the optical axis of the camera relative to the target in a first image of the target captured by the camera, and sends instructions to the motion mechanism to move the optical head according to the corrective movement to align the optical axis with the target.

Abstract: An illumination system for dark-field imaging may include one or more illumination sources providing temporally incoherent light with a first spatial profile, and two or more lens assemblies configured to direct the light from the one or more illumination sources as two or more illumination beams to a buried target along optical paths outside an objective lens of an imaging sub-system. The two or more illumination beams may fully overlap at the buried target to provide a common illumination field. The lens assemblies limit numerical apertures of the illumination beams to prevent specular reflection of the illumination beams from entering the objective lens. A respective one of the two or more lens assemblies includes a homogenizer to provide that a respective one of the two or more illumination beams has a second spatial profile with higher spatial uniformity than the first spatial profile according to a selected metric.

Abstract: An illumination system for dark-field imaging may include one or more illumination sources providing temporally incoherent light with a first spatial profile, and two or more lens assemblies configured to direct the light from the one or more illumination sources as two or more illumination beams to a buried target along optical paths outside an objective lens of an imaging sub-system. The two or more illumination beams may fully overlap at the buried target to provide a common illumination field. The lens assemblies limit numerical apertures of the illumination beams to prevent specular reflection of the illumination beams from entering the objective lens. A respective one of the two or more lens assemblies includes a homogenizer to provide that a respective one of the two or more illumination beams has a second spatial profile with higher spatial uniformity than the first spatial profile according to a selected metric.

Abstract: A wafer alignment system includes an imaging sub-system, a controller, and a stage. The controller receives image data for reference point targets and determines a center location for each of the reference point targets. The center location determination includes identifying sub-patterns within a respective reference point target and identifying multiple center location candidates for the respective reference point target. The step of identifying the multiple center location candidates for the respective reference point target includes: applying a model to each identified sub-pattern of the respective reference point target, wherein the model generates a hotspot for each sub-pattern that identifies a center location candidate for the respective reference point target.

Abstract: A wafer alignment system includes an imaging sub-system, a controller, and a stage. The controller receives image data for reference point targets and determines a center location for each of the reference point targets. The center location determination includes identifying sub-patterns within a respective reference point target and identifying multiple center location candidates for the respective reference point target. The step of identifying the multiple center location candidates for the respective reference point target includes: applying a model to each identified sub-pattern of the respective reference point target, wherein the model generates a hotspot for each sub-pattern that identifies a center location candidate for the respective reference point target.

Abstract: Notch detection methods and modules are provided for efficiently estimating a position of a wafer notch. Capturing an image of specified region(s) of the wafer, a principle angle is identified in a transformation, converted into polar coordinates, of the captured image. Then the wafer axes are recovered from the identified principle angle as the dominant orientations of geometric primitives in the captured region. The captured region may be selected to include the center of the wafer and/or certain patterns that enhance the identification and recovering of the axes. Multiple images and/or regions may be used to optimize image quality and detection efficiency.

Abstract: Notch detection methods and modules are provided for efficiently estimating a position of a wafer notch. Capturing an image of specified region(s) of the wafer, a principle angle is identified in a transformation, converted into polar coordinates, of the captured image. Then the wafer axes are recovered from the identified principle angle as the dominant orientations of geometric primitives in the captured region. The captured region may be selected to include the center of the wafer and/or certain patterns that enhance the identification and recovering of the axes. Multiple images and/or regions may be used to optimize image quality and detection efficiency.

Abstract: Automated comparison of tool recipes is described. A target recipe is digitally translated from a tool language to a standard language format to produce a translated recipe. The translated recipe is digitally compared to a source recipe that is also in the standard language format.