Dynamic test compaction for bridging faults

Abstract

We describe a dynamic test compaction procedure for four-way bridging faults. Under this fault model, a pair of lines g/sub i/, g/sub j/ is associated with four bridging faults corresponding to two possible combinations of opposite values on g/sub i/ and g/sub j/, and two options for the line whose value is faulty in the presence of the fault (either g/sub i/ or g/sub j/). Compaction is achieved by simultaneously considering faults that have a line g/sub i/ with a value /spl alpha//sub i/ in common, such that the value /spl alpha//sub i/ on g/sub i/ is affected by the presence of the fault. Faults with a common line g/sub i/ and value /spl alpha//sub i/ differ only in the second line g/sub j/ of each pair of bridged lines, and the second lines only need to be assigned the value /spl alpha/~/sub i/ in order to detect all the faults. This strong relationship between the faults allows us to derive tests that detect large numbers of these faults, resulting in compact test sets.