MEASUREMENT OF TRACE METALLIC CONTAMINANTS ON SILICON-WAFER SURFACES IN NATIVE AND DIELECTRIC SILICON-OXIDES BY VAPOR-PHASE DECOMPOSITION FLOW-INJECTION INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY

A highly sensitive multielement analytical method known as vapor phase decomposition flow injection inductively coupled plasma-mass spectrometry (ICP-MS) was developed and used to measure the concentration of trace metals on silicon wafer surfaces. The method uses hydrogen fluoride vapor to decompose and release metal contaminants from a surface oxide. These trace metals are then collected by scanning a small drop of dilute acid solution throughout the wafer surface. Trace metals in the solution are measured by ICP-MS using flow injection (FI) sample introduction. Potentially, 60 elements can be measured with detection limits ranging from 10(8) to 10(11) atom/cm2. Typical surface concentrations of trace metals on silicon wafers with native oxides and dielectric oxides were measured and presented.