A novel technique for in-line monitoring of micro-contamination and process induced damage

The use of a simple, rapid and nondestructive technique for inline monitoring of electrically active impurities introduced during wafer fabrication is reported. This AC surface photovoltage-based technique can determine the substrate doping type, doping concentration, oxide charge, and energy distribution of interface traps on both bare and oxidized silicon wafers without the formation of gate electrodes and substrate contacts. The technique is shown to have good reproducibility and resolution for quantifying the electrically active impurities, on the order of 1×10¹⁰ q/cm². Detection of contaminants and static charges by this technique is shown to correlate well with the electrical performance of thin dielectrics. The use of this technique for inline monitoring of very low levels of plasma-induced damage in the SiO₂/Si system is also discussed as is the potential for this tool in reducing furnace downtimes and in prompt identification of the source of contamination