De-clamping wafers from an electrostatic chuck
AssigneeAxcelis Technologies, Inc.
InventorsWilliam D. Lee, Ashwin M. Purohit, Marvin R. LaFontaine, Richard J. Rzeszut
Life of this patent
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Abstract
One embodiment of the present invention relates to a method for declamping a semiconductor wafer that is electrically adhered to a surface of an electrostatic chuck by a clamping voltage. In this method, the clamping voltage is deactivated. For a time following the deactivation, a first region of the wafer is lifted an first distance from the surface of the electrostatic chuck while a second region of the wafer remains adhered to the surface of the electrostatic chuck. A predetermined condition is monitored during the time. The second region is lifted from the surface of the electrostatic chuck when the predetermined condition is met.
Claims20
A method for de-clamping a wafer that is electrically adhered to a surface of an electrostatic chuck by a clamping voltage, comprising:
- deactivating the clamping voltage;
- for a time following the deactivation, lifting a first region of the wafer an first distance from the surface of the electrostatic chuck while a second region of the wafer remains adhered to the surface of the electrostatic chuck;
- monitoring a predetermined condition during the time;
- and
- lifting the second region from the surface of the electrostatic chuck when the predetermined condition is met.
A system for processing a wafer, comprising:
- an electrostatic chuck comprising a one or more electrodes operable to provide an electrostatic clamping force between the wafer and a surface of the electrostatic chuck;
- a power supply configured to provide a clamping voltage to the one or more electrodes;
- and
- a lifting assembly adapted to during a first time lift a first region of the wafer a first distance from the surface of the electrostatic chuck while a second region of the wafer remains on the surface, and further adapted to lift the entire wafer from the surface when a predetermined condition is met;
- a controller adapted to monitor the predetermined condition and provide control signals to the lifting assembly to lift the entire wafer from the surface when the predetermined condition is met.
A method for de-clamping a semiconductor wafer that is electrically adhered to a surface of an electrostatic chuck by a clamping voltage, comprising:
- deactivating the clamping voltage;
- for a time following the deactivation, mechanically lifting a first region of the wafer from the surface of the electrostatic chuck while a second region of the wafer remains adhered to the surface of the electrostatic chuck;
- monitoring a capacitance between the wafer and the electrostatic chuck during the time;
- and
- when the capacitance favorably relates to a threshold level, lifting the second region of the wafer from the surface of the electrostatic chuck to completely remove the wafer from the electrostatic chuck.
Dependencies are inferred from the claim text.