8-bit multiplier simulation experiments investigating the use of power supply transient signals for the detection of CMOS defects

Transient Signal Analysis is a digital device testing method that is based on the analysis of voltage transients at multiple test points. In this paper the power supply transient signals from simulation experiments on an 8-bit multiplier are analyzed at multiple test points in both the time and frequency domain. Linear regression analysis is used to separate and identify the signal variations introduced by defects and the variations caused by changes in fabrication process parameters. Defects were introduced into the simulation model by adding material (shorts) or removing material (opens) from the layout. Process parameter fluctuations were modeled by randomly varying transistor and circuit parameters individually and in groups over the range of +/-25% of the nominal parameters. The results of the analysis show that it is possible to distinguish between defect-free devices with injected process variation and defective devices.