Evaluation of Laser Scattering Technique and Spectroscopic Ellipsometry for In-Line Ion Implantation Characterization

Today, most semi-conductor fabrication units are looking for fast and cheap in-line characterization tools to develop and monitor each process step. In this study, we evaluated new ways to characterize as-implanted process by ion implantation with equipment typically dedicated for other applications. First, we will demonstrate how sensitive spectroscopic ellipsometry and laser scattering technique can be to slight changes in ion implantion parameters (i.e. energy, ion dose, tilt, etc.). Then, these results will be compared to classical in-line ion implantation doping characterization technique (i.e. Sheet resistance measurement). In this study, ion implantation has been realized on medium current ion implanters (E500 from Varian and NV-8200P from Axcelis). Two different species have been implanted (one heavy ion: Arsenic and one light ion: Hydrogen) into silicon with various energy, ion dose, tilt and beam uniformity. In-line characterization was performed on as-implanted wafers, using two differents means: i) a Woollam M2000 spectroscopic ellipsometer, working in the 0.7-6.5eV range and ii) the low frequency part of the scattered light (called "haze") of KLA-Tencor Sp1(DLS) particle counter. First promising results indicate that these techniques could be used to characterize in-line low-doping and no-doping species.