INCREASED THROUGHPUT FOR THE TESTING AND REPAIR OF RAMS WITH REDUNDANCY

This paper considers the problem of determining whether a redundant random-access memory (RRAM) containing faulty memory cells can be repaired with spare rows and columns. The approach is to increase the number of working RRAM's manufactured per unit time, rather than per wafer, by presenting 1) a computationally efficient algorithm for detecting unrepairability, 2) a computationally efficient algorithm for optimal repair for special patterns of faulty memory cells, and 3) on-line algorithms that can find an optimal repair or else detect unrepairability during memory testing, hence aborting unnecessary testing. Experimental validation of the approach is given which is based on industrial device fabrication data.