Prevention of Metal Contamination in Sub 50 nm SC1 Cleaning Process

Abstract

In this study, we investigated the relationship between particle removal efficiency (PRE), surface etch rate and removal of metal contaminant with various concentrations of SC1 cleaning solution. To identify the relationship between etch rate and the formation of defect, etch depth was measured for various compositions of SC-1 solution by using atomic force microscopy. Si wafers were contaminated with Cu ions and particles by dipping method. Cu precipitate and particles on Si surface were counted by using atomic force microscopy and a dark field optical microscope respectively to evaluate cleaning efficiency of SC1 solutions. The effect of SC1 compositions on Si etching was also investigated. It is observed that with increase in H2O2 concentration both Cu contamination and PRE decreases. This study suggests that the SCl cleaning solution needs to be optimized in order to achieve lower Cu contamination with a high PRE.