Side wall water outlet design for silicon wafer wet cleaning bath

Abstract

For the wet cleaning of 300-mm-diameter semiconductor silicon wafers, an additional water outlet in the wet cleaning bath was designed, particularly focusing on the pinhole arrangements on the side walls by the concept of the overlapping water removal regions. The water velocity vectors and the virtual particle paths based on numerical calculations showed that the water injected from two bottom inlets went up through the narrow space between the wafers, then horizontally flowed along the water surface and exited the bath. The calculations additionally indicated that the water recirculation in the upper half region of the bath could be reduced depending on the side wall pinhole arrangement. Simultaneously, the percent of removed particles was increased. Based on the experiments, the water in the bath remained colorless after the continuous supply of a blue-colored ink tracer for 90 s. For smoothly transporting away the contaminants, the side wall outlet design contributed to the simple water motions with less recirculation.