The Reaction of H202 and Ozone in Ammonium Hydroxide (NH4OH) Solutions with Silicon Wafers

Abstract

The main purpose of this study was to evaluate the ozone chemistry in NH4OH solutions in terms of oxidizing power and the contaminant removal efficiency when compared with H2O2 based NH4OH solution. Above pH values of 9, the solubility of ozone in solutions was almost nil at room temperature. However, ozone was dissolved in NH4OH solutions when the temperature of solutions was lowered to 10°C. Ozone was decomposed rapidly in NH4OH solutions within a few minutes. It was interesting to note that the hydrophobic silicon surface was passivated to the hydrophilic surface in ozone-injected NH4OH solutions within 10min. Chemical oxide grown in ozone-injected NH4OH solutions was removed by DHF solution in shorter time compared with SC1 oxide. Ozone-injected NH4OH solutions could not remove the particles on silicon surface effectively. However, ozone-injected NH4OH solutions combined megasonic power could efficiently remove particles compared with DI water/megasonic and dilute SC1/megasonic cleaning