Method for determining and classifying sram bit fail modes suitable for production test implementation and real time feedback

Abstract

A method () for determining various bit failure modes in a static random access memory device. A hard/soft bit failure test sequence is performed on each cell of the memory device to determine whether the cell exhibits a hard bit failure or a soft bit failure, then a data retention test is performed on the cell having soft bit failure to determine whether the cell exhibits a data retention failure. A write or disturb test sequence is then performed on the cell not having data retention failure, and a read or disturb test sequence is performed on the cell having write or disturb failure. Finally, a disturb test sequence is performed on the cell having read or disturb failure, and then an analysis is performed on the data from the tests to determine whether the cell exhibits one of a write, read, or disturb failure.