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Simultaneous Display of Voltage Paths and Signal Progression in an Integrated Circuit

IP.com Disclosure Number: IPCOM000082619D
Original Publication Date: 1975-Jan-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 67K

Publishing Venue

IBM

Related People

Lukianoff, GV: AUTHOR

Abstract

This system is capable of displaying voltage paths and functional progression through the circuitry of an integrated circuit. It consists of the superposition of two techniques of voltage detection and display: voltage display coding and stroboscopy.

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Simultaneous Display of Voltage Paths and Signal Progression in an Integrated Circuit

This system is capable of displaying voltage paths and functional progression through the circuitry of an integrated circuit. It consists of the superposition of two techniques of voltage detection and display: voltage display coding and stroboscopy.

Voltage coding provides visual information on path continuity and extensions. It generates a continuous display of codes representing voltage penetrated areas. The codes are sets of spatial stripes which, when viewed at TV speeds, move. However, the motion represents neither direction of current flow nor signal propagation, merely the voltage penetrated areas. See, for example, the publication by J.J. DeStafeno et al entitled, Display of Voltage Distributions on Microcircuit", IBM Technical Disclosure Bulletin, Vol. 15, No. 8, January, 1973, pages 2547-8.

The stroboscopic technique provides visual as well as electronic data about signal progression on the specimen. However, it does not provide a continuous trace of its own signal path, but only data on the instantaneous voltage location, which when viewed at TV rates, displays signal progression. See the article by Plows and Nixon, Stroboscopic Scanning Electron Microscopy, Journal of Scientific Instruments, 1968, Volume 45, pages 595 - 600.

The simultaneous use of both techniques provides both sets of data, with the paths outlined by coding and the signal moving along the paths.

Fig. 1 shows the basic system. The inputs to the sample comprise suitable potentials and pulses proposed thereon to a pulse generator. These sources, as well as the beam blanking unit for the scanning electron microscope (SEM), are controlled by a scan generator which pulses the electron beam in the microscope column with respect to the waveform on the sample. Hence, a stationary picture may be obtained at any chosen phase within the cycle. Defect localization in the sample can be accomplished by comparison between a proper and an incorrect path within the sample. The correct path stored in memory can be superimposed in a comparator with the actual path in the sample through a voltage detector. A difference of the signal spread indicates where the digression...