EES data analysis of lithography trouble detected by MapSSA

We performed automatic classification of wafer test maps and analyzed data for machines with trouble. We detected patterns that had periodicity in the fail chip distribution and performed the machine difference analysis. If the lithography process is the origin of the periodicity pattern, we classify it as a shot failure. We analyzed the machine data and specified the root cause of the shot failure. This method is very effective for specifying the apparatus with trouble.