Abstract: A wafer chuck includes alignment members that allows a semiconductor wafer to be properly aligned on the chuck without using a separate alignment stage. The alignment members may be cams, for example, attached to arms of the wafer chuck. These members may assume an alignment position when a robot arm places the wafer on the chuck. In this position, they guide the wafer into a proper alignment position with respect to the chuck. During rotation at a particular rotational speed, the alignment members move away from the wafer to allow liquid etchant to flow over the entire edge region of the wafer. At still higher rotational speeds, the wafer is clamped into position to prevent it from flying off the chuck. A clamping cam or other device (such as the alignment member itself) may provide the clamping.

Abstract: A chemical etching system provides a mixture of sulfuric acid and hydrogen peroxide and serves as the etchant for removing residual copper from an edge bevel region of a semiconductor wafer. The etching system includes a dilution module where concentrated sulfuric acid and concentrated hydrogen peroxide are diluted to the appropriate concentrations and then stored. To reduce the likelihood that oxygen bubbles (from hydrogen peroxide decomposition) will appear in the etchant solution, stored sulfuric acid and hydrogen peroxide are mixed immediately prior to use. In this manner, the dissolved oxygen concentration in the hydrogen peroxide decreases well below the saturation level.