Seed Ordering and Selection for High Quality Delay Test

This paper presents a seed ordering and selection method in LFSR-reseeding-based BIST for high quality delay test. The proposed method selects seeds based on the gain in the sum of the longest path lengths sensitized by seeds, which is highly correlated with statistical delay quality level (SDQL). We also evaluate the contributions of pseudo-random patterns in several mixed-mode BIST approaches and the impact of base seed set on the final quality of selected seeds. Experimental results show that the proposed method intelligently selects seeds and obtains significant reduction in seed count under SDQL constraint within a reasonable time.