Seed selection procedure for LFSR-based BIST with multiple scan chains and phase shifters

In this paper, we discuss the application of a seed-selection procedure for LFSR-based BIST to multiple scan chains, combined with a phase shifter. We introduced the procedures for selecting seeds and arrangement of phase shifters under the restriction of limiting additional hardware overheads, and evaluated them in respect to the number of test patterns required to achieve 100% fault coverage. Experimental results shows that that the test length was reduced in comparison with cases in which phase shifters or seed-selection procedures were not applied, under condition where the number of EOR gates in the phase shifter were restricted.