Abstract
The emergence of multiple core, high speed microprocessors in sub 90nm node technologies present challenges for defect localization, especially in SRAM logic circuits involving Array Built In Self Test (ABIST). Voltage sensitive, temperature sensitive and frequency sensitive soft defects in these ABIST logic circuits can spell the difference between pass and failure, especially for Silicon on Insulator (SOI) designs. High density SRAM arrays with ever shrinking critical dimensions in multiple core, high speed microprocessor designs dictate an increased number of ABIST logic circuits of complex hierarchical design. Scan chain diagnostics to pinpoint the failing scan latch logic circuit following ABIST testing frequently results in ever greater uncertainty; increased number of suspect circuits related to the failure. A case study analysis successfully applied to pinpointing a voltage sensitive logic circuit defect in a 90nm SOI design is described here, followed by root cause TEM analysis.
