CMOS IC reliability indicators and burn-in economics

Sensitive I/sub DDQ/ and LVMF (low V/sub DD/, maximum frequency) tests were done to examine reliability indicators and burn-in economics for CMOS ICs. These experiments used 3,495 CMOS 1 Mb SRAMs for special I/sub DDQ/ tests, LVMF tests, burn-in and life tests, and failure analysis. I/sub DDQ/ was measured at the maximum V/sub DD/ tolerated by the IC, ranging from 40% to 60% above the nominal V/sub DD/. These data indicate that elevated voltage I/sub DDQ/ screening can replace burn-in for CMOS ICs, including ICs from poor quality (rogue or maverick) lots. A low reliability risk group (27% of the population) that failed only I/sub DDQ/ tests was identified by I/sub DDQ/ signatures and life tests. Two other defect classes were examined for this yield reclamation potential for ICs that failed only I/sub DDQ/ tests.