Browse Prior Art Database

Electronic Measuring System

IP.com Disclosure Number: IPCOM000088460D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 3 page(s) / 69K

Publishing Venue

IBM

Related People

Pasello, R: AUTHOR

Abstract

This system is adapted for measuring semiconductor masks in the micron and submicron region. The basic principle of the system relies on electronic counting of pulses processed from the video signal provided by a TV camera and which represents the mask portion to be measured.

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Electronic Measuring System

This system is adapted for measuring semiconductor masks in the micron and submicron region. The basic principle of the system relies on electronic counting of pulses processed from the video signal provided by a TV camera and which represents the mask portion to be measured.

A block diagram of the system 10 is depicted in Fig. A. Located above the mask 11, where the measurements are to be made, are a microscope 12 associated with a TV camera 13, which provides, on bus 14, the video signal which corresponds to the electronic scanning of the mask and which results from the conversion of the optical image into electronic form.

The line and scan synchronisation signals are first extracted from the video signal (block 15). The synchro signals are then applied to circuit 16 to generate two gates X and Y under operator control 17 in both horizontal and vertical positions. The gates will appear on the TV monitor 19 simultaneously with the video signal after being surintensified in circuit 18 and appropriately amplified in the video amplifier 20. In addition, circuit 18 provides inhibition signals for a "start" comparator 21 and a "stop" comparator 22, which also receive the video signal from amplifier 20. The outputs of these comparators are connected to an electronic counter 23.

This system may be understood by turning to Fig. B, where a portion of the mask to be measured is represented. It is proposed to measure the gap between the two patterns. The video signal which...