IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Thursday Sessions
       Session EL-ThA

Paper EL-ThA10
SR-TXRF for the Investigation of the Deposition Mechanism of Trace Cu Impurities on Si Wafer Surfaces

Thursday, November 1, 2001, 5:00 pm, Room 124

Session: In-Situ Semiconductor Characterization
Presenter: K. Baur, Stanford Synchrotron Radiation Laboratory
Authors: K. Baur, Stanford Synchrotron Radiation Laboratory
T. Homma, Waseda University, Japan
J. Tsukano, Waseda University, Japan
M. Watanabe, Komatsu Electronic Metals, Japan
A. Singh, Stanford Synchrotron Radiation Laboratory
S. Brennan, Stanford Synchrotron Radiation Laboratory
P. Pianetta, Stanford Synchrotron Radiation Laboratory
Correspondent: Click to Email
Total Reflection X-ray Fluorescence (TXRF) spectroscopy using synchrotron radiation is one of the most powerful techniques for trace impurity analysis on Si wafer surfaces. In addition, among the more sensitive techniques, it is the only one that is non-destructive. We present the status of the transition metal analysis activity at the Stanford Synchrotron Radiation Labororatory (SSRL) which has matured to a point where a facility exists at which semiconductor companies are able to perform industrially relevant measurements at state of the art detection limits. This facility features clean wafer handling and automated data acquisition making routine analytical measurements possible. The best sensitivity demonstrated to date is 3.4 E7 atoms/cm2 for a 5000 second count time corresponding to 7.6 E7 atoms/cm2 for a standard 1000 second count time. This is more than a factor of 100 better than what can be achieved with conventional TXRF systems. A new development at SSRL is the investigation of the deposition mechanisms of trace metal impurities during a wet cleaning process on Si wafer surfaces. This is considered to be influenced by the oxidation conditions at the silicon wafer surface. This study requires high surface sensitivity and renders Synchrotron Radiation TXRF the technique of choice. We will present our results on the deposition mechanism of Cu trace impurities on Si wafers immersed into ultra pure water, focussing on the correlation between the deposited Cu concentration and the amount of dissolved oxygen present in the ultra pure water.