Scatterometry of Nano-Particles on Silicon Wafer

With the advancing development of the semiconductor industry, optical resolution of EUV lithography has shrinked to 13nm. In the preceding inspection process of unpatterned silicon wafer, the resolution of nano-metrology of 12.5nm has been realized. For better improving the resolution of nano-metrology in unpatterned silicon wafer, more precise modelling of scatterometry is necessary. Metrology of silicon wafer is standardized with Polystyrenelatex (PSL) and metallic nano-spheres. Rayleigh scattering of PSL and metallic nano-particles in the three dimensional space is modeled and analyzed with Bidirectional Reflectance Distribution Function. Given the setting up of a simplified dark field inspection system and the established Rayleigh scattering BRDF model, the impact of different parameters on the polarized Rayleigh scattering of nano-particles on the silicon wafer are evaluated. The comprehensive analysis in this article provides a theoretical foundation for the following system design and upgradation.