Investigation Of Critical Path Selection For In-Situ Monitors Insertion

The performance and low power requirement are becoming more and more challenging to fulfill for consumer product. On the opposite, a low failure rate at SoC level must be guaranteed to the end-customer. In that context, the insertion of in-situ slack monitor is known to be promising and efficient solution to manage the wear-out and more generally to minimize all margins related to manufacturing variations and operating conditions. As far as in-situ slack monitors are located in functional path, the choice of endpoint register and the number of monitors are of prime importance. This paper deals with a methodology of path selection in a context of monitor insertion in digital block without pattern availability. Basically, the timing of data path arriving to an endpoint register is analyzed, and a weight is calculated as a figure of merit. This work accounts for stochastic dispersion, aging, global corner process, voltage and temperature variations. The important role played by the sub critical path is illustrated with silicon measurement.