Patent ID: 8712575

Claim:
A method of processing a semiconductor wafer using a double side grinder of the type that holds the wafer between a pair of grinding wheels and a pair of hydrostatic pads during a grinding operation, the method comprising: establishing a first hydrostatic pressure in the hydrostatic pads to initially clamp the wafer during a first stage of the grinding operation, measuring the amount of electrical current used by the grinding wheels of the double side grinder, determining the stage of the grinding operation based on the measured amount of electrical current used by the grinding wheels of the double side grinder, reducing the hydrostatic pressure to a second hydrostatic pressure lower than the first pressure during grinding of the wafer in a second stage of the grinding operation, and increasing the hydrostatic pressure to a third hydrostatic pressure during a third stage of the grinding operation to clamp the wafer and to thereby improve nanotopology in the processed wafer.