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Simultaneous Spatial Frequency Coding of Different Kinds of Information in Scanning Electron Microscopy

IP.com Disclosure Number: IPCOM000078526D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Touw, TR: AUTHOR

Abstract

In systems for precoding voltage distributions on microcircuits in terms of spatial frequencies in a scanning electron microscope image (as disclosed in IBM Technical Disclosure Bulletin Vol. 15, No. 8, pages 2547, 2548 and 2549, January 1973), the coding carries information about the sources of the voltage occurring at a given location on the microcircuit. The information about the magnitude of the voltage is contained in the amplitude of the coded image signal. On the other hand, FM scanning electron microscopy (SEM) (as disclosed in IBM Technical Disclosure Bulletin Vol. 15, No. 7, pages 2298 and 2299, December 1972) allows coding of the signal amplitude at a point of a SEM image into spatial frequencies independently of the contrast mechanism, and, in particular, independently of the source of a voltage-contrast signal.

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Simultaneous Spatial Frequency Coding of Different Kinds of Information in Scanning Electron Microscopy

In systems for precoding voltage distributions on microcircuits in terms of spatial frequencies in a scanning electron microscope image (as disclosed in IBM Technical Disclosure Bulletin Vol. 15, No. 8, pages 2547, 2548 and 2549, January 1973), the coding carries information about the sources of the voltage occurring at a given location on the microcircuit. The information about the magnitude of the voltage is contained in the amplitude of the coded image signal. On the other hand, FM scanning electron microscopy (SEM) (as disclosed in IBM Technical Disclosure Bulletin Vol. 15, No. 7, pages 2298 and 2299, December 1972) allows coding of the signal amplitude at a point of a SEM image into spatial frequencies independently of the contrast mechanism, and, in particular, independently of the source of a voltage-contrast signal.

These two methods may be combined and used simultaneously, to code different kinds of information about the microcircuit in the same image. The resultant image has voltage-signal sources coded in one (discrete) set of spatial frequencies, and local voltage magnitude coded independently in another (continuous) set of spatial frequencies.

The system combines a set of signal generators for precoding voltage-signal sources by frequencies and/or pulse parameters, and a voltage-controlled generator operating on the precoded AM video signal to code...