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

Since the nineties non-Si based materials are introduced at an accelerated pace in the research and development for advanced micro-electronic devices or micro electric mechanical systems (MEMS). Several of the materials contain elements from the Pt-group with e.g. metal gates (Ru, Pt, Ir, IrO_2), ferro-electric materials (Pt, Ir, IrO_2), seed layers for interconnects (Pd) and MEMS (Pt, Ru, RuO_2, Rh, Pd, Os). The controlled introduction of these materials in clean room environments requires the availability of efficient detection methods such as VPD-DC-TXRF. The Pt-group elements however exhibit electropositive reduction potentials with respect to Si wafers and a more problematic collection of these metals is expected, similar to the well-known case of Cu contamination [1]. In this paper, we investigate the feasibility of a VPD-DC-TXRF method for Pt-group elements in comparison with Cu.