Screening minVDD outliers using feed-forward voltage testing

MinVDD testing using full vector set search routines consumes too much test time. A 3-step process is proposed using: (1) a reduced vector set (RVS) binary search to measure the intrinsic (defect free) minVDD for a die; (2) a feed-forward to the full vector set (FVS) for low voltage testing; and (3) delta VDD and nearest neighbor residual statistical post-processing (SPP) are applied to the data to screen the minVDD outliers that are identified using the RVS binary search. RVS vs. FVS correlation data is shown on 3 products. Data shows minVDD yield fallout of 0.2-0.8% and 20% of the minVDD outliers shows significant VDD shifts in burn-in.