Browse Prior Art Database

High Speed Automatic Particle Counter

IP.com Disclosure Number: IPCOM000082778D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Shaw, WP: AUTHOR [+2]

Abstract

This surface defect detector is capable of counting surface defects on an entire semiconductor wafer in the micron and submicron size range.

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High Speed Automatic Particle Counter

This surface defect detector is capable of counting surface defects on an entire semiconductor wafer in the micron and submicron size range.

A semiconductor wafer to be inspected is placed directly under a TV pickup camera having a field of view consisting of the entire wafer surface. The wafer surface is illuminated by light sources 1 and 2 mounted 90 degrees apart, and at an angle of incidence to the wafer surface of about 5 degrees. Light reflected or scattered by particles on the wafer surface is picked up by a sensitive TV camera.

The output of the camera is amplified and passed to a detection circuit which controls a TV monitor and/or a digital counter. Response time for an entire wafer is about one second, making the detector suitable for automatic wafer inspection techniques. The visual display allows other imperfections such as scratches, stains, fingerprints and similar defects to be identified.

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