Semiconductor wafers are positioned in a cleaning tank and subjected to sequential flows of one or more highly diluted cleaning solutions that are injected into the lower end of the tank and allowed to overflow at the upper end. One solution comprises one part ammonium hydroxide, two parts hydrogen peroxide,...http://www.google.com.au/patents/US5950645?utm_source=gb-gplus-sharePatent US5950645 - Semiconductor wafer cleaning system