Importance

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Abstract

A system and method for holding a semiconductor wafer substantially flat on a chuck and for cooling the chuck is provided. The system for securing a wafer on a chuck includes first and second conduits, first and second valves, and a first sensor. The first and second conduits each fluidly connect a first plurality of holes in the chuck to a vacuum source. The first and second valves are disposed within the first and second conduits respectively. The first sensor is in fluid communication with one of the first and second valves. The first sensor measures a first vacuum level applied to one of the first and second valves. In operation, one of the first and second valves opens to induce a vacuum force between the first plurality of holes in the chuck and a wafer disposed on the chuck. When the first vacuum level applied to one of the first and second valves is greater than a predetermined vacuum level, the wafer has been partially pulled down against the chuck. Thereafter, the other valve of first and second valves opens to increase the first vacuum force. The system further includes a cooling gas source fluidly connected to the first conduit. When the first valve is open, the cooling gas source urges gas to flow through the first plurality of holes to cool the chuck.

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First Claim