Collection efficiency of metallic contaminants on Si wafer by vapor-phase decomposition-droplet collection

The collection efficiency of metallic contaminants on four different types of silicon wafers was investigated. P, p(+), n and n(+)-type polished silic on wafers were used for the substrate, and 14 metallic elements (Na, Mg, Al , K, Ca, Cr, Fe, Mn, Co, Ni, Cu, Zn, Mo and Ti) were contaminated on silico n wafer surface. Vapor-phase decomposition-droplet collection (VPD-DC) was employed as the sample preparation procedure. For the collecting solution, HNO3, HF and a mixture of HF and H2O2 were used, respectively. A liquid dro plet collecting metallic contaminants during VPD-DC was analyzed by inducti vely coupled plasma-mass spectrometry (ICP-MS). As a result, it was found t hat HNO3 and HF were not suitable for collecting Cu. Copper was not collect ed completely in HNO3 and HF. A mixture of HF and H2O2 is the most effectiv e to collect all of the tested metallic elements, regardless of the dopant concentration and type of substrate.