The University of North Carolina at Charlotte

The University of North Carolina at Chapel Hill

Rafic Zein Makki

Thomas Paul Weldon

David M Binkley

Ali Chehab

Richard F Greene

Farid M Tranjan

Kasra Daneshvar

Methods and apparatus are provided for testing to determine the existence of defects and faults in circuits, devices, and systems such as digital integrated circuits, SRAM memory, mixed signal circuits, and the like. In particular, methods and apparatus are provided for detecting faults in circuits, devices, and systems using input control signals to generate controlled-duration, controlled pulse-width, transient power supply currents in a device under test, where said transient power supply currents are of controllable bandwidth and can be used as observables to determine faulty or defective operation. Additionally, methods and apparatus are provided to permit high bandwidth sensing of transient supply currents as need to preserve the narrow widths of these current pulses. These methods may include autozero techniques to remove supply current leakage current and DC offsets associated with practical current sensing currents. The sensed transient supply currents can be compared to single or multiple thresholds to assess normal or faulty or defective operation of the device under test.

Methods and apparatus for testing electronic circuits

Internal test sites on integrated circuit chips may be tested with minimal input/output pad or chip area overhead by providing transient interconnections to the internal test sites using an optically activated photoconductive layer which is formed over the active device layers of the integrated circuit to be tested. The photoconductive layer may be optically activated using an optical mask or hologram, to electrically access the desired internal test sites. Different test sites may be tested using different masks or holograms. The photoconductive layer is preferably hydrogenated amorphous silicon which is highly compatible with standard integrated circuit processing.

Electro-optical method and apparatus for testing integrated circuits

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Charlotte, NC, United States of America

Rafic Zein Makki