Investigation of metallic contamination analysis using vapor phase decomposition - droplet collection - total reflection X-ray fluorescence (VPD-DC-TXRF) for Pt-group elements on silicon wafers

摘要

The conventional VPD-DC-TXRF method seems not applicable to the Pt-group elements because of dependency of the collection on the chemical state and a limited kinetics of dissolution. Further development of this method for the noble elements might benefit from more innovative ideas such as using underetching in the VPD step, use of electrochemical power, or specific complexing agents. An alternative preconcentration method might be found in the droplet sandwich etch (DSE) method, with a clear advantage of a longer contact time and less dependency on the wetting properties of the applied solution and substrate. Current contamination monitoring is advised to apply methods without chemical preconcentration such as Direct-TXRF monitoring and preferable Sweeping-TXRF for better statistical control.