Post-CMP Cleaning of InGaAs Surface for the Removal of Nanoparticle Contaminants for Sub-10nm Device Applications

Abstract

In this study, the development of post-chemical mechanical polishing (CMP) protocols for cleaning abrasive nanoparticles from In0.53Ga0.47As surfaces was systematically analyzed. Abrasive silica nanoparticles (130 and 289 nm) were intentionally deposited onto InGaAs surfaces. Various concentration ratios of chemical etchants such as HCl and H2O2 were used to control material loss and surface oxides of InGaAs. The optimal concentration ratio of the HCl/H2O2 cleaning solution exhibited 40% particle removal efficiency (PRE). Application of megasonic (MS) cleaning improved the PRE to 80%. To prevent particle re-contamination, ammonium dodecyl sulfate (ADS) was used as an anionic surfactant to modify surface charge in the InGaAs substrate. Addition of surfactant further improved the PRE to over 96%. Optimal cleaning of InGaAs surfaces was achieved with a combination of HCl/H2O2, surfactant, and MS.