Uniform deposition method of monodispersed SiO₂ nanoparticles on a 300-mm Si wafer surface

A study of the uniform deposition of nanoparticles across a 300-mm wafer was conducted to assess the uniformity of the wafer center-to-edge cleaning technique. A new method of particle deposition was devised different from the conventional method using electrostatic force. The strategy implements wafer rotation and deposition through principles of convection and diffusion. In this study, we focused on the effect of wafer rotation speed on particle deposition. After determining optimum conditions, fine results were obtained with a well-deposited shape and an excellent particle size uniformity of above 70% over the entire area of the wafer except in unusual cases. Deposition results were confirmed with KLA-Tencor Surfscan SP5 commonly used by foundries, and logic and memory manufacturers around the world to increase node development and production. The inherent index of the refraction value by Surfscan SP5 caused a particle size shift in measurement results. However, scanning electron microscopy and scanning mobility particle sizer analysis results revealed that 80-, 60-, 40-, 30-, and 20-nm-sized silica nanoparticles were well deposited on the wafer. Through this research, we believe that standard wafers processed with this particle deposition method will be useful for performance evaluation of wafer cleaning technology and calibration of wafer inspection technology during development.