Crosstalk- and Process Variations-Aware High-Quality Tests for Small-Delay Defects

The population of small-delay defects (SDDs) in integrated circuits increases significantly as technology scales to 65 nm and below. Therefore, testing for SDDs is necessary to ensure the quality and reliability of high-performance integrated circuits fabricated with the latest technologies. Commercial timing-aware automatic test pattern generation (ATPG) tools have been developed for SDD detection. However, they only use static timing analysis reports in the form of standard delay format for path-length calculation and neglect important underlying causes, such as process variations, crosstalk, and power-supply noise, which can also induce small delays into the circuit and impact the timing of targeted paths. In this paper, we present an efficient pattern evaluation and selection procedure for screening SDDs that are caused by physical defects and by delays added to paths by process variations and crosstalk. In this procedure, the best patterns for SDDs are selected from a large repository test set. Experimental results demonstrate that our method sensitizes more LPs, detects more SDDs with a much smaller pattern count, and needs less CPU runtime compared with a commercial timing-aware ATPG tool.