Abstract
Traditional fault based scan ATPG stuck-at, transition-delay and small-delay defect and custom multi-transition fault model based patterns have been used as the primary DFT scan test content for many years to guarantee zero defects on automotive designs. Continued analysis to reduce DPPB on multiple automotive designs confirmed presence of subtle cell-internal defects that were not getting screened out using the traditional set of fault model based patterns and, motivated us to evaluate and integrate defect-oriented cell-aware tests on automotive designs. In this paper, we will first discuss the cell-aware pattern generation flow followed by the enhanced test program flow that was used to screen and identify unique cell-aware only failures from a new product introduction design. Later, we will review the deep-dive findings from the first unique cell-aware failure on a new design. ATE silicon characterization, failure analysis findings and ATPG simulation along with CMOS transistor level explanation of how cell-aware transition-delay patterns were more effective in screening out the defective unit when compared to traditional transitional-delay patterns will be discussed in detail.
