Browse Prior Art Database

Defect Scanner for Repetitive Patterns

IP.com Disclosure Number: IPCOM000080912D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Thomas, DR: AUTHOR

Abstract

This semiconductor array pattern defect scanner allows manufacturing introduced optical defects to be detected.

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Defect Scanner for Repetitive Patterns

This semiconductor array pattern defect scanner allows manufacturing introduced optical defects to be detected.

A semiconductor mask 10, or other work piece, containing repetitive patterns is placed on a support, not shown, and the repetitive pattern is scanned by a high-resolution imaging device, such as a television image orthicon device 12. The video signal is split and one part sent to a delay unit 14, which provides a time delay corresponding to the periodicity of the pattern. The other part of the signal is sent to a differential amplifier 16. Both signals are differentially sensed to detect differences in the input signal, corresponding to differences in the image of each pattern.

The error, or defect, signal from amplifier 16 is sent to a storage system 18, which retains a record of the time and position of the defects for realtime or latter review. Sensitivity to electronic drift and other imaging relating problems caused by dual image monitoring are reduced by utilizing only a single input device. By comparing repetitive patterns during a single scan, inaccuracies caused by physically stepping from one pattern to another are eliminated.

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