<p>Apparatus and methods for a wafer handling system that manipulates semiconductor wafers. The invention includes an end effector having a vacuum chuck, an internal vacuum plenum, and flow diverters positioned within the vacuum plenum that define vacuum distribution channels coupled in fluid communication with vacuum ports of the vacuum chuck. The invention also includes a vacuum chuck having flow diverters positioned in one or more internal vacuum plenums that are in fluid communication with the vacuum ports of the vacuum chuck. The flow diverters adjust the vacuum pressure supplied to the vacuum ports such that, as vacuum ports are occluded by the wafer, the vacuum pressure is preferentially applied to unblocked vacuum ports for increasing the attractive force applied to unengaged portions of the wafer. The apparatus of the present invention has particularly utility for securing thin semiconductor wafers with a significant warpage.</p>
