Modification of DHF for removal of metals from silicon wafer

Abstract

In this study, we modified DHF (Dilute Hydrofluoric acid) cleaning solution using various additives such as ozone and chelating agents to control metallic contaminants on silicon (Si) surface. Metal contaminations, Cu and Al, were intentionally deposited on Si surface by a dipping method to evaluate the effect of additives on metal removal. MRE (Metal Removal Efficiency) was measured by atomic force microscopy. By optimizing the concentration of additives in DHF, more than 95% of MRE was achieved. Cu was not easy to remove when compared with Al in chelating agent added DHF solutions. However, DHF with ozone showed higher and equal removal efficiency in both Cu and Al contaminants. © The Electrochemical Society.