Abstract
Even though failure analysis performed with a latest generation Phemos 2000 Optical Beam Induced Resistance Change (OBIRCH) tool has given excellent results for 120nm and 90nm technology developments, the limitations of tool and technique become apparent when used for the 65nm technology node and beyond. This article discusses the use of a pulsed laser in combination with a lock-in amplifier for OBIRCH-based fault isolation in latest generation CMOS devices. Using such set-up with appropriate settings for laser pulse frequency, scan speed, and phase shift off-set, a ten-fold signal-to-noise ratio gain is achieved. This improved S/N ratio allows detecting faulty circuitry with higher sensitivity and isolating faults that cannot be detected with the traditional OBIRCH set-up. Various case studies on latest technology devices are presented to illustrate the interest of adding the lock-in capability to the standard OBIRCH tool.
