Development of post InGaAs CMP cleaning process for sub 10nm device application

Abstract

In this study, a systematic analysis was carried out on the chemistry of post-CMP cleaning solution that should be able to clean the In0.53Ga0.47As substrate with low defectivity and minimal material loss. First, various concentrations of HCl and H2O2 solutions were used to measure the etch rate of wafer surface. Then, the zeta potential and surface states of InGaAs were measured using a zeta potential analyzer and X-ray photoelectron spectroscopy (XPS), respectively. For the cleaning test, the nano silica particles (130 and 289 nm) were intentionally deposited on the substrate surface. The optimized concentration ratio of the HCl/H2O2 solution was used for the wafer cleaning which showed around 40% particle removal efficiency (PRE). The application of megasonic (MS) improved the PRE to 80%. However, the addition of a surfactant with MS further improved the PRE over 96%. The combination of HCl/H2O2 with a surfactant and MS is proposed as a cleaning method for the InGaAs surface with minimal material loss and reduced oxide content. © VDE VERLAG GMBH Berlin Offenbach