SBIR Phase II: Focused Beam Total Reflection X-Ray Fluorescence Analysis Using Doubly-Curved Crystals

This Small Business Innovation Research (SBIR) Phase II project proposes to meet the demand from the microelectronics industry for improved wafer contamination analysis. Wafer contamination control is critical for Ultra Large Scale Integrated (ULSI) technology and there is a strong demand for a non-destructive analytical tool with improved sensitivity and spatial resolution over the conventional total x-ray fluorescence (TXRF) method. A new technique, focused beam TXRF, can meet this important market need. Based on point-focusing toroidal crystal optics, focused beam TXRF will improve the spatial resolution by a factor of more than 100 and provide 30 times better detection sensitivity for local contaminants on Si as compared to the conventional TXRF method. This technique also has potential for low-level Al, Na and other low Z elements analysis on Si that cannot be addressed effectively by the conventional TXRF and other techniques. In this project, preliminary focused beam TXRF data will be collected using WL1 excitation provided by a toroidal Si (220) crystal to demonstrate the improvement of sensitivity and resolution for transition metal detection. Theoretical calculation will be also carried out to determine the feasibility for Al and Na detection for wafer contamination control at 10^ 9 to 10^10 atoms/cm^2 level. Focused beam TXRF analysis has commercial applications in the microelectronics industry for wafer contamination control including localized and homogeneous contaminants with high resolution. These contaminants include many important elements such as transition metals, Al, Na and other low Z elements. By being able to identify these contaminants, the quality of silicon wafers can be improved. This will be a tremendous cost savings to a multi-billion dollar industry