Defect tool monitoring of process equipment by AIT fusion

PowerChip (PSC) Fab 12A is a newly built 300 mm DRAM fab in Taiwan. PSC Fab 12A has identified that blank wafer defect monitoring is not adequate at 300 mm due to high test wafer cost and reduced process tool productivity. Aditionally, integration defects and some tool-induced defects do not occur on blank test wafers. For these reasons PSC 12A wanted to investigate using patterned product wafers for tool monitoring. This work describes how a patterned wafer tool monitor method was implemented for ion implantation process tools using a KLA-Tencor AIT fusion darkfield defect inspection tool. The method included the use of automatic defect classification (iADC) to provide high signal to noise for the defects of interest.