Is Built-In Logic Redundancy Ready for Prime Time?

Chris Allsup
Synopsys, Inc.


With each new process generation, it becomes ever more challenging to maintain high yields of integrated circuits. Progressively lower yields potentially undermine the profits of semiconductor companies across all industry segments. Embedding redundant logic into designs can improve product yields, but is this economically viable for most systems-on-chip? This paper attempts to answer this fundamental question. After describing an example architecture for built-in logic redundancy (BILR), we examine precisely how the BILR design and test parameters affect the area overhead, test execution time and yield of the redundant system. After conveying the cost model, we present analysis results showing that redundancy could be cost-effective, depending on a number of cost infrastructure variables that include the parameters of the BILR system itself.