International Business Machines Corporation

Douglas Y Kim

Kurt R Muller

Kenneth A Bird

Lawrence D Thorp

Stephen J Kish

Julius J Lambright

Karl Otto Muggenburg

An optical system for a beam scanning apparatus comprises a laser beam, a cylindrical first lens, a scanning mirror rotatable about an axis for deflecting and scanning the focused energy beam and a concave, toroidal mirror adapted to deflect the focused energy beam from the rotating mirror and collimate the beam. The toroidal mirror has a radius in a major axis equal to the focal length of the first lens and a radius in a minor axis equal to twice the focal length of the first lens, and is spaced from the first mirror a distance equal to the focal length of the first lens. Preferrably, the axis of rotation of the scanning mirror is non-orthogonal with respect to the direction of the beam from the first lens.

Facet tracking correction system for laser scanners

A calibration system for circuit inspection tools in which analog threshold levels are automatically set by digital signals. The inspection too includes an optical detector system that provides video signals to channels each containing an analog processor. In the analog processor an analog reference signal, an analog video inspection signal which may contain a defect indication and a digital threshold signal are employed. The digital threshold signal is converted into an analog threshold signal which is summed with the analog reference signal that has been inverted. The inverted, thresholded reference signal is then summed with the analog video signal. The summed analog video signal and thresholded reference signal is compared with a zero level. If the sum is greater than zero a defect is indicated.

Automatic threshold level structure for calibrating an inspection tool

A method and apparatus for the inspection and handling of surface level defects is taught. Briefly stated, the object to be inspected is positioned. A Laser light is polarized into at least one orientation and then reflected off of a rotated polygon mirror. This causes the light to 'move' over the area of interest. A plurality of fiber optic bundles are used to receive and conduct the reflected light back to photomultipliers. The photomultipliers convert the light into electrical signals while associated electronics digitize the signals, keeping track of pixels which are produced. By keeping track of pixel edge boundaries and determining if certain thresholds are exceeded or not met as appropriate, the area of interest can be checked for a variety of defects. By comparison of the defects to a reference base, the defects and hence the items inspected can be categorized.

Method and apparatus for object inspection

A method and apparatus for the inspection and handling of surface level defects is taught. Briefly stated, the object to be inspected is positioned. A Laser light is polarized into at least one orientation and then reflected off of a rotated polygon mirror. This causes the light to 'move' over the area of interest. A plurality of fiber optic bundles are used to receive and conduct the reflected light back to photomultipliers. The photomultiplers convert the light into electrical signals while associated electronics digitize the signals, keeping track of pixels which are produced. By keeping track of pixel edge boundaries and determining if certain thresholds are exceeded or not met as appropriate, the area of interest can be checked for a variety of defects. By comparison of the defects to a reference base, the defects and hence the items inspected can be categorized.

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Poughkeepsie, NY, United States of America

Douglas Y Kim