Spatial mapping of non-uniform time-to-breakdown and physical evidence of defect clustering

For the first time, we report a spatial mapping methodology to directly obtain spatial BD distributions from TDDB data at wafer-scales. The results reveal BD defects are strongly clustered towards later stress times and explain the root-cause of non-Poisson area-scaling in agreement with recently developed time-dependent clustering model [3,4]. This methodology provides important detailed information for process diagnosis and improvement as well as realistic reliability assessment in future technologies as variability issues continue to rise.