A wafer grinding system includes a robot arm having a suction board at one end and a table within reach of the robot arm. An upper surface of the table has a vacuum surface for sucking and holding wafers. A pusher coupled to the robot arm extends about the periphery of the suction board. The pusher flattens wafers against the upper surface of the table, allowing the table to hold by suction wafers that would otherwise be too bowed to be held in that way. Additionally, a table can have a vacuum area that is small in comparison to the wafers, which is another way of increasing the magnitude of wafer bow that can be tolerated. A grinding system can use the reduced vacuum area concept to allow the positioning table to hold bowed wafers and the pusher concept to allow the chuck tables to hold bowed wafers.