Water Motion over a Wafer Surface Rotating in a Single-Wafer Wet Cleaner

Abstract

Water motion over a 200-mm diameter wafer surface rotating in a single-wafer wet cleaner was observed and calculated, by means of the water flow visualization technique and the computational fluid dynamics, respectively. The tracer, the blue-colored ink, injected from the wafer center symmetrically spread over the rotating wafer surface from its center to the edge. The radial velocity of the water was nearly constant over the wafer surface except at its center area. The water layer thickness in the rotation rate range, approximately 0.1 mm, gradually decreased with the increasing rotation rate. The tracer injected from non-center positions tended to be localized in the peripheral region of the wafer, particularly at the high rotation rates.