| 摘要 |
In accordance with an embodiment of the invention, a step in a fabrication process can be conducted so as to determine when the process has reached an end point. End point detection can be performed by detecting when a operating process condition changes. For example, in one embodiment, a step in a fabrication process (e.g., an etching step) can be conducted in a chamber by varying a position of a throttle valve connected to the chamber so as to maintain a desired pressure within the chamber. In such method, it can be determined when the etching step has reached an end point by detecting when a signal representative of the throttle valve position changes in a particular way which matches an expected signature. In another embodiment, a step in a fabrication process can be conducted in a chamber by maintaining a desired flow within the chamber, such as by controlling a throttle valve, and allowing the pressure within the chamber to vary. In such method, it can be determined when the step has reached an end point by detecting when a signal representative of the pressure changes. In a particular embodiment in which end point detection is based on change in pressure, the throttle valve can be maintained at a particular position when conducting the step in the fabrication process.
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