Ade Corporation

Aeronca Electronics, Inc.

James David Hunt

Lee Dante Clementi

Michael L Smith

Richard D Vander Neut

Charles J Cushing

Charles A Monjak

W Jerry Alford

James L Wilkes

Full surface maps of slope and height are determined for the surface of a highly smooth surface such as a silicon wafer, by an apparatus which includes a light source for creating a light beam and scanning and wafer transport systems which cause the incident beam to be scanned over the full surface of the wafer. A quad cell light detector is positioned to receive the beam specularly reflected from the wafer surface, the quad cell detector having four cells arranged in quadrants with each cell providing an electrical signal indicative of the amount of light received by the cell. A processor is programmed to calculate changes in spot location on the detector based on the signals from the cells, and to calculate changes in surface slopes based on the changes in spot location. Full maps of X- and Y-slope are produced, and a line integration algorithm is used for calculating full surface height maps. Regions of surface height gradient exceeding a threshold are flagged as defects by the processor.

Method and apparatus for mapping surface topography of a substrate

A system for laser scanning a relatively movable reflective surface element and inspecting that surface by monitoring the reflected energy in both light and dark channel receivers. Flaws occurring on the surface of the element, depending on the types of flaws, cause various frequency components to be present in the reflected energy and affect the amount of energy reflected to the light and dark channel receivers. Circuitry is included to detect and classify the various types of flaws as they are scanned, to compute the condition of the inspected element and to grade that inspected element as being in an acceptable state or in one of a plurality of unacceptable states. The described reflective surface element is a silicon wafer of the type used as the base substrate in fabricating integrated circuits and other electronic components.

Surface inspection scanning system

Growing community of inventors

Charlotte, NC, United States of America

James David Hunt