Ade Optical Systems Corporation

Ade Corporation

Estek Corporation

Lee Dante Clementi

Michael E Fossey

John C Stover

Songping Gao

James David Hunt

Charles A Monjak

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 surface inspection system and method is provided which detects defects such as particles or pits on the surface of a workpiece, such as a silicon wafer, and also distinguishes between pit defects and particle defects. The surface inspection system comprises an inspection station for receiving a workpiece and a scanner positioned and arranged to scan a surface of the workpiece at the inspection station. The scanner includes a light source arranged to project a beam of P-polarized light and a scanner positioned to scan the P-polarized light beam across the surface of the workpiece. The system further provides for detecting differences in the angular distribution of the light scattered from the workpiece and for distinguishing particle defects from pit defects based upon these differences.

Wafer inspection system for distinguishing pits and particles

The composition of a particle occurring on the surface of a smooth substrate is identified by impinging the surface with a light beam having a strong P-polarized component at an oblique angle of incidence to the surface, and collecting light scattered from the surface at forward, center, and back locations relative to the portion of the surface impinged by the incident beam. The intensities of the light collected at these locations are measured by detectors and converted into signals, and the magnitudes of the signals are compared to correlations of particle material as a function of the relative magnitudes of the forward-, center-, and back-scatter signals so as to identify the material whose correlation most nearly matches the measured detector signals. Preferably, a ratio of the back detector signal magnitude to forward detector signal magnitude is correlated with particle material and back detector signal magnitude. Alternatively or additionally, a ratio of back detector signal magnitude to center detector signal magnitude is correlated with particle material and back detector signal magnitude. Average particle diameter versus back detector signal magnitude is correlated with particle material.

Methods and apparatus for identifying the material of a particle

A surface inspection system and methods of inspecting a surface of a workpiece are provided for detecting particles, defects, or other surface characteristics in or on a surface of the workpiece. The surface inspection system preferably has a transporter arranged for transporting a workpiece along a material path and a rotator associated with the transporter and arranged for rotating a workpiece during translational travel along the material path. A scanner is positioned and arranged for scanning a surface of a workpiece during rotational and translational travel along the material path. The scanner preferably includes a light source arranged to generate a light beam therefrom and a deflector positioned to receive the light beam and arranged for deflecting the light beam along a predetermined scan path across a surface of the workpiece as the workpiece rotationally and translationally travels along the material path. A collector also is preferably arranged for collecting light specularly reflected and scattered from the surface of the workpiece during rotational and translational travel along the material path.

Surface inspection system and method of inspecting surface of workpiece

The particle detection system detects particles or flaws on the surface of an article. The system has a source of light directed against the surface of the article and a detector for detecting light scattered from the article and indicative of the presence of particles or flaws present on the article. The detector includes a light collector positioned for receiving and collecting light scattered from the surface of the article, a light splitter cooperating with the collector for dividing the collected light into first and second light collect components, first and second photodetectors positioned for receiving respectively first and second like light components, and an electrical circuit for combining the output signals from the first and second photodetectors to form a combined output signal with a higher signal-to-noise ratio than traditional systems.

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Lake Wylie, SC, United States of America

Lee Dante Clementi