Motorola Corporation

University Patents, Inc.

Thomas W Peterson

Frank W Fischer

Donald R Pettit

A method for coating a substrate with a coating solution. In a first step (31), a semiconductor wafer is placed on a turntable. In a second step (32), the substrate is spun at a high speed and a coating solution is dispensed onto the substrate. In a third step (33), the turntable is spun at a low speed and additional coating solution is dispensed onto the substrate.

Method for coating a substrate with a coating solution

The disclosed invention employs an optical heterodyne technique that depends upon coherent detection of phase modulated light from individual particles, and does not depend on measurement of light scattered at a specific angle from particles. A collimated coherent beam of light is generated and separated into a subject beam and a reference beam. The subject beam is focused at the inspection region and light is gathered from the inspection region. The gathered light and the reference beam are combined and a photodetector is responsive to the combined light for producing an electrical signal representative of the combined light. The phase shift of light scattered from an individual particle passing through the inspection region is then determined by measuring the power in the phase modulated sidebands of the electrical signal. The phase shift is indicative of the size of the particle passing through the inspection region.

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Tucson, AZ, United States of America

Thomas W Peterson