Differential process control method
AssigneeGlobiTech Incorporated
InventorsDanny Kenny, Keith Lindberg
Life of this patent
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Abstract
A system and method for monitoring a process flow of a semiconductor wafer. In one embodiment, the method initially calculates a first location of the wafer before it is processed. The wafer is then moved into a process chamber where it is processed. Then a second location of the wafer is calculated before the wafer is unloaded. If the difference between the first and second locations are within a predetermined amount, the wafer is unloaded and regular processing steps proceed. If the difference is not within the predetermined amount, an alarm is activated and the process is stopped.
Claims3
A method for monitoring a process flow of a semiconductor wafer, the method comprising the steps of:
- calculating a first offset value indicative of the location offset between the nominal location of the wafer and the actual location of the wafer before processing;
- moving the wafer into a process chamber for processing;
- processing the wafer;
- calculating a second offset value indicative of the location offset between the nominal location of the wafer and the actual location of the wafer after processing;
- comparing said first offset value with said second offset value;
- determining if a difference between the first and second offset values is greater than a predetermined amount;
- and
- activating an alarm if the difference is greater than the predetermined amount.
Dependencies are inferred from the claim text.