Partial scan selection for user-specified fault coverage

With current approaches to partial scan, it is difficult, and often impossible, to achieve a specific level of fault coverage without returning to fill scan. In this paper, we introduce a new formulation of the minimum scan chain assignment problem and propose an effective covering algorithm and test sequence generator SCORCH (Scan Chain Ordering with Reduced Cover Heuristic) to solve it. SCORCH uses a combinational test generator not only to optimize the scan chain assignment, subject to maintaining a user-specified level of fault coverage, brit also as a basis for the test sequence generation. We report experimental results with minimized partial scan assignment and 100% fault coverage for a set of large benchmarks