FEASIBILITY OF IN SITU TXRF

摘要

Synchrotron radiation based total external reflection x-ray fluorescence spectroscopy (TXRF) isrnnow being routinely used at the Stanford Synchrotron Radiation Laboratory (SSRL) to carry outrnindustrially relevant measurements. For transition elements on Si wafer surfaces, detectionrnlimits of 8×10~7 atoms/cm~2 that correspond to 1 impurity atom among 30 million substrate atomsrnhave proven more than adequate for the studies undertaken to date. New studies, which aim torndevelop a better understanding of the kinetics of metal deposition during Si wafer cleaningrnprocesses, are being pursued. By using a sample cell with a water delivery system that has beenrncustom designed, silicon samples can be analyzed directly beneath a water layer (in situ TXRF).rnInitial results measuring silicon samples with known Cu concentrations are presented. Due tornthe increased scatter and background from the water layer along with the attenuation ofrnfluorescence signals, minimum detection limits for the in situ TXRF setup increased to 8x1010rnatoms/cm~2, in close agreement to predicted values extracted from modeling calculations.