Adsorption and surface reaction of isopropyl alcohol on SiO2 surfaces

Abstract

In this study, we investigated the adsorption and surface reaction of isopropyl alcohol (IPA) gas on silicon dioxide (SiO2) surfaces. The temperature dependence of the decomposition behavior of IPA and the effect on the SiO2 surface, such as reduction of SiO2 during IPA treatment, were studied. The chemical structures of the SiO2 surfaces before and after IPA treatment were analyzed by x-ray photoelectron spectroscopy (XPS). The decomposition behavior of IPA was investigated using an in-line evaluation system equipped with a SiO2 reactor and Fourier-transform infrared spectroscopy (FT-IR). During IPA treatment at temperatures above 150 °C, different types of organic matter were deposited on the SiO2 surfaces depending on the temperature. SiO2 was not reduced, and its surface states were not changed at temperatures below 350 °C. In addition, we investigated the amount of trimethylaluminium (TMAl) adsorbed on SiO2 surface with and without IPA treatment. As a result, the amount of TMAl adsorbed on SiO2 surface was reduced by about 25% by the IPA treatment. We found that the organic matter obtained by IPA treatment partially inhibited the adsorption of the TMAl gas on SiO2 surfaces. These findings will be useful for the use of IPA in the advanced semiconductor manufacturing such as in area-selective processes.