Browse Prior Art Database

Display of Voltage Distributions on Microcircuits

IP.com Disclosure Number: IPCOM000078524D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

DeStafeno, JJ: AUTHOR [+3]

Abstract

A system for display of voltage distributions on a microcircuit 1 uses a scanning electron microscope (SEM) 2, equipped with a voltage-sensitive detector 3. The output signal from this detector normally produces an image on a CRT display 4. The normal image contains information about voltage distribution mixed with other unrelated information, e.g. topography and materials composition.

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Display of Voltage Distributions on Microcircuits

A system for display of voltage distributions on a microcircuit 1 uses a scanning electron microscope (SEM) 2, equipped with a voltage-sensitive detector 3. The output signal from this detector normally produces an image on a CRT display 4. The normal image contains information about voltage distribution mixed with other unrelated information, e.g. topography and materials composition.

To distinguish voltage information from other information, voltage signals are applied to the microcircuit 1 by a number of signal or pulse generators 5, of adjustable frequencies or pulse repetition rates f(1), f(2), . . . , f(n). The temporal frequency of each generator 5 is translated by the scanning process into a spatial frequency in the image on the display 4. These spatial frequencies depend also on the line and frame scanning frequencies produced by scan generator 6. Additional control of the spatial frequencies may be obtained by triggering or gating each generator 5, by using signals 7 derived from the scan generator 6, e.g. the line scan sync pulse.

Each input signal from generators 5 is coded as a specific spatial frequency in the displayed image. Those portions of a microcircuit dependent on more than one of the generators, are distinguishable by a mixture of the corresponding spatial frequencies in the displayed image.

The wave shapes or pulse shapes from generators 5 are not critical, but may be conveniently chosen to...