A circuit for voltage coding synchronizing

The appearance of stationary stripes in a voltage contrast SEM image of a circuit, generally known as voltage coding, is a commonly used technique for tracing circuit lines for failure analysis and for locating nodes for waveform measurements. Maintaining a steady striped image requires synchronizing a pattern generator to the SEM raster scan. A circuit is described which can be attached to any SEM to perform this synchronization, and which has a number of features which extend the usefulness of voltage coding. Copyright © 1990 Foundation for Advances in Medicine and Science, Inc.