Interferometer system, positioning system, a lithographic apparatus, a jitter determination method, and a device manufacturing method
AssigneeASML Netherlands B.V.
InventorMaarten Jozef Jansen
Life of this patent
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Abstract
An interferometer system includes an optics system configured to allow a first light beam to travel along a measurement path including a target, and a second light beam to travel along a fixed reference path excluding the target; and a signal generator configured to introduce a power-modulated optical signal in the measurement path or the reference path to determine jitter caused by components of the interferometer system downstream of the signal generator.
Claims20
An interferometer system comprising:
- an optics system configured to allow a first light beam to travel along a measurement path arranged to include a target, and a second light beam to travel along a fixed reference path arranged to exclude the target;
- a signal generator configured to introduce a power-modulated optical signal in the measurement path or the reference path;
- a detector system at an end of the measurement path and the reference path to receive the first and second light beams, the detector system comprising one or more detectors;
- and
- a processing unit configured to determine a phase of the first and/or second light beam based on the power-modulated optical signal received at the detector system and to determine jitter caused by components of the interferometer system downstream of the signal generator.
A method for determining jitter in an interferometer comprising a light source configured to emit a first light beam and a second light beam, and an optics system configured to allow the first light beam to travel along a measurement path including a target, and the second light beam to travel along a fixed reference path excluding the target, and wherein the method comprises:
- introducing a power-modulated optical signal in the measurement path or the reference path;
- detecting the power-modulated optical signal after traveling along the measurement path or the reference path;
- determining a phase of the detected power-modulated optical signal;
- and
- determining the jitter from the determined phase of the detected power-modulated optical signal.
Dependencies are inferred from the claim text.