Non-Visual Defect Monitoring with Surface Voltage Mapping

Abstract

Non-Visual Defects (NVD) is a category of semiconductor material and process induced defects that cause electrical failures, but are not detected with visual wafer inspection tools. This paper gives an overview of our non-contact electrical NVD metrology that uses fast whole wafer inspection with standard mm resolution Kelvin probe surface voltage mapping. In an advanced approach detected NVDs are mapped in high resolution (μm range) using Force Kelvin Probe Microscopy. In depth NVD characterization is done with the corona-Kelvin method that quantifies dielectric and interfacial properties in the defect site. This characterization is performed in a non-invasive fluence range of corona charging and all measurements are non-contact, and do not require fabrication of test devices. A broad application range is demonstrated with examples relevant to silicon IC, silicon photovoltaics and to wide bandgap epitaxial SiC.