By Oguz Yavas, Ernst Richter, Christian Kluthe & Markus Sickmoeller, Qimonda AG
A recent collection of data on 90nm, 80nm and 75nm technology from state-of-the-art 300mm wafer fabs have been brought together to perform a comprehensive analysis of wafer-edge yield engineering. For this study, a dedicated cross-functional team thoroughly investigated wafer periphery using innovative tools such as yield test chips and advanced process inspection. Critical processes were identified and countermeasures implemented to improve overall yield performance. Best practice sharing within the fabrication cluster resulted in a significant learning speed that supported an aggressive global production ramp. The challenges and the methodology used to address fast wafer-edge yield learning in Dynamic Random Access Memory (DRAM) manufacturing are the focus of this paper.