Image Number 18 for United States Patent #7456113.
The present invention is a method of use of a novel cleaning solution in a single wafer cleaning process. According to the present invention the method involves using a cleaning solution in a single wafer mode and the cleaning solution comprises at least ammonium hydroxide (NH.sub.4OH), hydrogen peroxide (H.sub.2O.sub.2), water (H.sub.2O) and a chelating agent. In an embodiment of the present invention the cleaning solution also contains a surfactant. Moreover, the present invention also teaches a method of combining an ammonia hydroxide, hydrogen peroxide, and chelating agent step with a short HF step in a fashion that minimizes process time in a way that the entire method removes aluminum and iron contamination efficiently without etching too much oxide.The single wafer cleaning processes may also be used to increase the yield of high-grade reclaimed wafers.