Modification of copper and copper oxide surface states due to isopropyl alcohol treatment toward area-selective processes

The reduction of copper oxide by isopropyl alcohol (IPA) gas and its mechanism were investigated toward the selective process of copper (Cu) wiring. Also, the decomposition behavior of IPA gas and surface modification during the IPA treatment on Cu and copper oxide surfaces were studied. Two samples were measured: Cu surface having native oxide film and a metal Cu surface after a hydrogen reduction treatment. The decomposition and reaction behaviors and adsorption characteristics of IPA were investigated using the inline evaluation system equipped with a Cu reactor and Fourier transform infrared spectroscopy. The chemical structures of the Cu and copper oxide surfaces before and after IPA treatment were analyzed by x-ray photoelectron spectroscopy. Based on the experiments, the process condition to induce reduction of copper oxide by IPA gas during the Cu processes temperature range was identified. It was also found that different organic matter derived from IPA was adsorbed on each surface.