The present disclosure relates to a wafer cleaning module for post CMP processes that reduces defects (e.g., watermarks, deposited particles) on a substrate, and an associated method. In some embodiments, the wafer cleaning module has a cleaning tank that may receive a semiconductor substrate within a cleaning medium. A pusher is may vertically move the semiconductor substrate from a starting position within the cleaning tank to an ending position. A position sensor may determine a position of the semiconductor substrate relative to a meniscus of the cleaning medium. Based upon the determined position, a control unit is may adjust a location of the starting position to a predetermined distance below the meniscus.