Deterministic test for the reproduction and detection of board-level functional failures

A common scenario in industry today is “No Trouble Found” (NTF) due to functional failures. A component on a board fails during board-level functional test, but it passes the Automatic Test Equipment (ATE) test when it is returned to the supplier for warranty replacement or service repair. To find the root cause of NTF, we propose an innovative functional test approach and DFT methods for the detection of boardlevel functional failures. These DFT and test methods allow us to reproduce and detect functional failures in a controlled deterministic environment, which can provide ATE tests to the supplier for early screening of defective parts. Experiments on an industry design show that functional scan test with appropriate functional constraints can adequately mimic the functional state space well (measured by appropriate coverage metrics). Experiments also show that most functional failures due to stuck-at, dominant bridging, and crosstalk faults can be reproduced and detected by functional scan test.