Passivation and Etching of Wafer Surfaces in HF-H2O2-IPA Solutions

Abstract

The etching behavior of silicon and oxide wafers was evaluated in HF solutions with and without the addition of H2O2 and IPA. The etch rates of SiO2 and Si were dependent on the concentrations of additives such as H2O2 and IPA in HF solution. As the concentration of H2O2 increased, the etch rates of SiO2 and Si increased. However, the etch rate of SiO2 decreased as the concentration of IPA increased in HF solutions. The etch rate of SiO2 in HF–H2O2–IPA solution was very similar to that in HF–IPA solutions. The etch rate was predominantly dependent on IPA concentration and not on H2O2 concentration. Particulate and metallic contamination removal efficiencies were evaluated in dilute HF solutions were added to which H2O2 and IPA. Fumed silica and Al2O3 particles were effectively removed in HF–H2O2–IPA. Cu removal efficiency from wafer surfaces markedly increased as the IPA and H2O2 were added into HF solution.