VOLTAGE MEASUREMENTS ON INTEGRATED-CIRCUITS USING A TIME-OF-FLIGHT ELECTRON SPECTROMETER

The time-of-flight (TOF) electron spectrometer offers significant adva ntages in terms of speed of data-acquisition over the retarding-field spectrometer commonly used in electron-beam test (EBT) machines. It me asures the time taken for a short pulse of secondary electrons to trav el from the specimen surface to a fast microchannel plate detector pla ced some way up the electron-optical column. Results are presented for an experimental setup based on a standard scanning electron microscop e column with an additional ''single-pole'' final lens which allows a relatively large unobstructed working distance above the specimen. Met hods for the rapid extraction of quantitative voltage data are describ ed.