placing a first semiconductor wafer on a wafer chuck in a process chamber;

producing a first plasma for processing the first semiconductor wafer by exciting a first gas from a gas dispenser, such that a first feature is formed on a central region of the first semiconductor wafer and a second feature is formed on an edge region of the first semiconductor wafer, wherein the central region of the first semiconductor wafer has a circular area, and the edge region of the first semiconductor wafer has a ring area surrounding the central region, and the gas dispenser is positioned above the wafer chuck;

removing the first semiconductor wafer from the process chamber;

placing a second semiconductor wafer into the process chamber;

measuring a first dimension of the first feature, and measuring a second dimension of the second feature;

calculating a first difference between the first dimension of the first feature and a first predetermined dimension through a process control system, and calculating a second difference between the second dimension of the second feature and a second predetermined dimension through the process control system;

determining whether the first difference is acceptable through the process control system, and determining whether the second difference is acceptable through the process control system;

in response to the determination determines that the first difference of the central region of the first semiconductor wafer is not acceptable, adjusting a first vertical distance between the gas dispenser and the wafer chuck;

in response to the determination determines that the second difference of the edge region of the first semiconductor wafer is not acceptable, adjusting a second vertical distance between an upper edge ring surrounding the wafer chuck and the gas dispenser; and

after adjusting the first and second vertical distances, producing a second plasma for processing the second semiconductor wafer by exciting a second gas from the gas dispenser.

placing a first semiconductor wafer above a top surface of a wafer chuck in a process chamber, wherein the top surface extends in a horizontal direction;

dispensing a processing gas through a gas dispenser, wherein the gas dispenser is positioned above the wafer chuck in a vertical direction;

producing a plasma for processing the first semiconductor wafer by exciting the processing gas, such that a first feature is formed on a central region of the first semiconductor wafer, and a second feature is formed on an edge region of the first semiconductor wafer;

measuring a first dimension of the first feature, measuring a second dimension of the second feature;

calculating a first_difference between the first dimension of the first feature, formed through the process chamber, and a first predetermined dimension through a process control system, and calculating a second difference between the second dimension of the second feature, formed through the process chamber, and a second predetermined dimension through the process control system;

determining whether the first difference is acceptable through the process control system, and determining whether the second difference is acceptable through the process control system;

placing a second semiconductor wafer into the process chamber;

in response to the determination determines that the first difference of the central region of the first semiconductor wafer is not acceptable, controlling a shape of the plasma in the vertical direction by adjusting a first vertical distance between the gas dispenser and the wafer chuck; and

in response to the determination determines that the second difference of the edge region of the first semiconductor wafer is not acceptable, controlling the shape of the plasma in the vertical direction by adjusting a second vertical distance between an upper edge ring surrounding the wafer chuck and the gas dispenser.