At-speed scan testing may suffer from severe yield loss due to the launch safety problem, where test responses are invalidated by excessive launch switching activity (LSA) caused by test stimulus launching in the at-speed test cycle. However, previous low-power test generation techniques can only reduce LSA to some extent but cannot guarantee launch safety.… (More)
The high test power consumption, which can be several factors higher than the functional power consumption for which an integrated circuit (IC) is designed, may result in higher overall cost due to yield loss and potentially damaged ICs. As system-on-chips (SOCs) designed in modular fashion are becoming increasingly common, the testing can, in contrast to… (More)
Research on low-power scan testing has been focused on the shift mode, with little or no consideration given to the capture mode power. However, high switching activity when capturing a test response can cause excessive IR drop, resulting in significant yield loss. This paper addresses this problem with a novel low-capture-power X-filling method by… (More)
This paper describes the VirtualScan technology for scan test cost reduction. Scan chains in a VirtualScan circuit are split into shorter ones and the gap between external scan ports and internal scan chains are bridged with a broadcaster and a compactor. Test patterns for a VirtualScan circuit are generated directly by one-pass VirtualScan ATPG, in which… (More)
IR-drop-induced malfunction is mostly caused by timing violations on activated critical paths during the capture cycle of at-speed scan testing. A critical-path-aware <i>X</i>-filling method is proposed for reducing IR-drop, especially on gates that are close to activated critical paths, thus effectively preventing test-induced yield loss.