Patent ID: 7396022

Claim:
A chuck capable of receiving a wafer and capable of rotating, a first region being formed by an area between the chuck and the wafer, a second region being adjacent to the wafer on a side of the wafer opposite the first region, the chuck comprising: a vacuum groove, capable of providing a low pressure suction force at a first end, said first end capable of securing the wafer; at least one venturi hole for lowering an air pressure in the first region in response to a rotation of said chuck; at least one air inlet hole for increasing the air pressure in the first region when said chuck rotates; a plurality of inlet holes, wherein a size of the inlet holes that are closer to a center of the chuck are larger than a size of the inlet holes that are farther from the center of the chuck, wherein said pressure in said first region is reduced using said at least one venturi hole and said at least one air inlet hole to substantially match a pressure of the second region, wherein the at least one air inlet hole has a larger opening than the at least one venturi hole.