A Probe of Chemical Oxide Growth Conditions

摘要

We propose that the species of wet chemical oxidant determine the level of oxide interface stress that is induced by the oxidation process. We have observed that the type of chemical finish present on a bare silicon wafer may affect the intensity of the reflected beam in thermal reflection spectroscopy (Therma-probe). Therma-probes measure changes in thermal conductivity that can be related to stress. For example, the change in stress caused by implantation is measured using a Therma-probe by testing monitor wafers before and after implantation. However, some types of silicon wafers interfere with this stress measurement by giving a very high or non-uniform signal before implantation. Sub-surface damage has been thought to be the cause. However, we will show in this paper that the level of near-surface stress measured by the Therma-Probe reading may be correlated with the type of chemical oxidant.