Advanced via inspection tool (AVIT)

US5216485A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Kenneth A. Bird · New Paltz, US
• Douglas Y. Kim · Poughkeepsie, US
• Stephen J. Kish · Hyde Park, US
• Julius J. Lambright · Hopewell Junction, US
• Kurt R. Muller · Hopewell Junction, US
• Lawrence D. Thorp · Yorktown, US

Key dates

• Filing date: Sep 4, 1991
• Grant date: Jun 1, 1993
• Expiry date: Sep 4, 2011

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2021/95615
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

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.