Application of laser scattering and optical defect detection methods to SIMOX-SOI wafers

Most major microprocessor manufacturers have said that silicon-on-insulator (SOI) is on their respective technology roadmaps, and at least one has already started shipping SOI based processors. As circuit sizes and densities continue to increase, and SOI applications expand, the accompanying need to further reduce defect levels in SOI wafers makes accurate defect metrology more important; improved metrology subsequently enables further defect reduction to be pursued. Metrology tools using laser light scattering to detect defects on bare silicon wafers, and optical imaging approaches used on patterned wafers, require special considerations when applied to SIMOX-SOI wafers. The purpose of this work is to further understand the issues and optimize the capabilities of optical defect detection methods for SIMOX-SOI wafer and circuit production. Improved capabilities will enable further reduction in SIMOX-SOI process related defects.