Test-cost optimization in a scan-compression architecture using support-vector regression

Scan compression is widely used in high-volume testing of complex integrated circuits. With an increase in design complexity, the increased density of unknown (X) values from output responses reduces compression efficiency. In order to effectively block X values and maximize the effectiveness of test compression, a scan-compression architecture has recently been proposed, in which deterministic test patterns can be loaded into selected scan cells by controlling the initial state of the pseudo-random pattern generator (PRPG). A careful selection of the PRPG length is however essential to reduce test cost. We propose an optimization method based on support-vector regression to determine the PRPG length for test-cost reduction in a given scan-compression architecture. A correlation-based feature selection methodology is also proposed to reduce the amount of data needed for the accurate selection of the PRPG length. Experimental results on industrial designs highlight the effectiveness of the proposed method.