A novel DFT technique for critical bridging faults in CMOS and BiCMOS ICs

This paper presents a technique for on-chip detection of (resistive) Bridging Faults (BFs) in CMOS (and BiCMOS) circuits, that improves the state of the art of testing in the following aspects: 1) compared with off-chip I_DDQ testing, it is much faster; 2) compared with on-chip Built-In Current Sensors (BICS), it avoids the use of extra devices in series with the functional circuits; 3) compared with both techniques, it is inherently selective, because it detects only BFs producing extra delays in excess of specified maximum values; 4) it can be used for on-line testing. The method of this work must be applied in addition to functional testing, that takes care of stuck-at and equivalent faults. In the case of buffers, our approach can be slightly modified to also detect stuck-at faults