REMOVAL OF PARTICLES ON SI WAFERS IN SC-1 SOLUTION

We have investigated the relationship between particle removal efficie ncy and etched depth in SC-1 solution (the mixture composed of ammoniu m hydroxide, hydrogen peroxide and DI water) for Si wafers. The Si etc hing rate increases with increasing NH4OH (ammonium hydroxide) concent ration. The particle removal efficiency depends on the etched Si depth , and is independent of NH4OH concentration. The minimum required Si e tching depth to get over 95% particle removal efficiency is 4 nm. Part icles on the Si wafers exponentially decrease with increasing the etch ed Si depth. However the particle removal efficiency is not affected b y particle size ranging from 0.2 to 0.5 mum. The particle removal mech anism on the Si wafers in SC-1 solution is dominated by the lift-off o f particles due to Si undercutting and redeposition of the removed par ticle.