New results and algorithms for MCM substrate testing

Substrate testing is critical to cost-effective MCM (multichip module) production. The authors formulate this problem as the verification of a set of trees using k-probes, and present linear-time algorithms for optimal probe generation. The algorithms yield near-optimal probe sets for complete fault coverage. It is shown that the associated probe scheduling problem is metric, and a bounded-error scheduling heuristic is obtained. Furthermore, an insertion-based heuristic is presented which exploits the special structure of 3-pin and the power/ground nets in the MCM substrate. This heuristic significantly improves probing costs over previous methods. Simulations using industry benchmarks show reductions in testing costs of up to 21% over the best previous methods