Formal Test Point Insertion for Region-based Low-Capture-Power Compact At-Speed Scan Test

Launch-Switching-Activity (LSA) is a serious problem during at-speed testing of integrated circuits, since localized LSA may lead to severe IR-drop and thus failures. The excessive LSA is conventionally mitigated by reducing the switching activity through special low-power test generation techniques, typically resulting in severe test pattern inflation and high test costs. This work introduces a novel concept of Low-Capture-Power Test Points (LCP-TPs), which are inserted to reduce switching activity in critical High-Capture-Power (HCP) regions. LCP-TPs also help in retaining high test compaction capability. An optimization- SAT based procedure is proposed to compute a small set of optimal LCP-TP locations for compact at-speed test sets with effective capture power reduction. Experimental results clearly demonstrate the advantages of LCP-TP insertion.