Pre-Filter For A Servo Control Loop, And Applications Thereof
AssigneeASML Holding N.V.
InventorRoberto B. Wiener
Life of this patent
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Abstract
A method, system and computer program product to control position of an error control module in a lithography apparatus using a servo control loop is described herein. The system comprises a filter, a servo controller coupled to the filter and configured to receive a control signal and an actuator coupled to the servo controller and configured to control the position of the error control module. The filter is configured to filter the control signal by modulating the amplitude and phase of the control signal in a desired frequency range, prior to the servo control loop.
Claims20
A servo control loop, comprising:
- a filter configured to filter a first control signal received from a module by modulating an amplitude and phase of the first control signal, in a desired frequency range;
- a servo controller configured to receive the filtered first control signal and a third control signal and to provide a second control signal therefrom;
- and
- an actuator coupled between the servo controller and the module and configured to receive the second control signal and to provide the third control signal therefrom, the third signal being received at the module and configured to control the module.
A method, comprising:
- filtering a first control signal received from a first module using a filter by modulating amplitude and phase of the first control signal in a desired frequency range;
- summing the filtered first control signal and a third control signal received from an actuator;
- producing a second control signal from the filtered first control signal and the third control signal using a servo controller;
- receiving the second control signal at the actuator;
- and
- controlling an error control module using the third control signal.
A computer program product comprising a computer useable medium including control logic stored therein for controlling the position of a module in a lithography apparatus, comprising:
- first control logic means for causing a computer to filter a first control signal received from a first module by modulating amplitude and phase of the first control signal in a desired frequency range;
- second control logic means for causing a computer to sum the filtered first control signal and a third control signal received from an actuator;
- third control logic means for causing a computer to provide a second control signal from the filtered first control signal and the third control signal;
- and
- control logic means for causing a computer to control an error control module using the third control signal.
A computer-readable medium containing instructions for controlling at least one processor of a host computer by a method comprising:
- filtering a first control signal received from a first module using a filter by modulating amplitude and phase of the first control signal in a desired frequency range;
- summing the filtered first control signal and a third control signal received from an actuator;
- producing a second control signal from the filtered first control signal and the third control signal using a servo controller;
- receiving the second control signal at the actuator;
- and
- controlling an error control module using the third control signal.
Dependencies are inferred from the claim text.