Test compaction by test cube merging for four-way bridging faults

Abstract

Test compaction that accommodates the constraints of test data compression can be achieved by generating test cubes for target faults, and then merging the test cubes. This paper describes an improved test cube merging procedure for four-way bridging faults. The procedure is motivated by the prevalence of bridging defects and the fact that test sets for bridging faults are larger than test sets for single stuck-at faults. A four-way bridging fault g_i/a_i/h_i models the case where a value a_i of a line h_i dominates the value of a line g_i. A basic test cube merging procedure considers a set of test cubes C_det that detects target faults. The paper extends the set of test cubes to include, in addition to C_det, a set of test cubes C_dom that assign values to dominating lines. Test cubes from C_dom have significantly fewer specified values than test cubes from C_det. When test cubes from C_dom are merged with test cubes from C_det, each resulting test cube detects more faults, and fewer test cubes are needed for detecting the same set of target faults.