Automatic test pattern generation for maximal circuit noise in multiple aggressor crosstalk faults

Decreasing process geometries and increasing operating frequencies have made VLSI circuits more susceptible to signal integrity related failures. Capacitive crosstalk is one of the causes of such kind of failures. Crosstalk fault results from switching of neighboring lines that are capacitively coupled. Long nets are more susceptible to crosstalk faults because they tend to have a higher coupling capacitance to overall capacitance ratio. A typical long net has multiple aggressors. In generating patterns to create maximal crosstalk noise, it may not be possible to activate all aggressors at the same time. Therefore, pattern generation must focus on activating a maximal subset of aggressors weighted by actual coupling capacitance values. This is a variant of max-satisfiability problem. Unlike a traditional max-satisfiability problem, here we must deal with signal propagation to an observable output. In this paper, we present a novel solution that combines 0-1 Integer Linear Program (ILP) with traditional stuck-at fault ATPG. The maximal aggressor activation is formulated as a linear programming problem while the fault effect propagation is treated as an ATPG problem. The problems are separated by min-cut circuit partitioning technique based on Kernighan-Lin-Fiduccia-Mattheyses (KLFM) method. This proposed technique was applied to ISCAS 85 benchmark circuits. Results indicated that 75-100 % of the aggressors could be switched for generating crosstalk noise while satisfying requirement of sensitizing a path to the output. I