Robust testability of primitive faults using test points

Abstract

Recent research has characterized a class of faults, called primitive faults, that must be tested to insure timing correctness of digital circuits. Experimental results have shown that a large fraction of primitive faults usually have only non-robust tests. In this paper, we propose a method of improving robust coverage of primitive faults using test point insertion. An important feature of the proposed method is that instead of considering primitive faults explicitly, single faults are analyzed to determine whether they can be members of robustly testable primitive faults. If not, test points are specified to make any primitive fault containing such faults robustly testable. Results of experiments to determine the effectiveness of the proposed method show significant improvements in fault coverage.