Removal of Organic Wax and Particles on Final Polished Wafer by Ozonated DI Water

Abstract

In this study, new cleaning process which has low cost of ownership (CoO) has been developed with ozonated DI water (DIO₃). Ozone concentration of 40 ppm at room temperature is used to remove the organic wax film and particles. Thicker than 200 Å of wax residues were still remained after commercial dewaxer treatment only. DIO₃treatment instead of a dewaxer showed the low removal rate on thick wax layer of 8000 Å due to diffusion limited reaction of ozone. A dewaxer was combined with DIO₃rinse to reduce wax removal time and remove wax residues completely. Replacing DI rinse with DIO3 rinse resulted in the surface with contact angle lower than 5˚ which indicates no further cleaning steps required. Particle removal efficiency (PRE) also improved further by combining SC-1 cleaning step with DIO₃rinsing process. The reduction of process time was obtained by introducing DIO₃cleaning with dewaxing process.