Measurement method and apparatus, exposure apparatus
AssigneeCanon Kabushiki Kaisha
InventorKazuki Yamamoto
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Abstract
A measurement method for measuring a wavefront aberration of a target optical system using a measurement apparatus that measures the wavefront aberration of the target optical system by detecting an interference pattern includes the steps of measuring as a system parameter a shift from a design value of a value that defines a structure of the measurement apparatus and the target optical system, and measuring the wavefront aberration of the target optical system using the system parameter.
Claims6
A measurement method for measuring a wavefront aberration of a target optical system by detecting an interference pattern formed by light passing through the target optical system, said measurement method comprising the steps of:
- obtaining a process parameter including at least one of a thickness of a member that generates the interference pattern, a distance between the member and an image sensor that takes an image of the interference pattern, a central coordinate of the interference pattern on the image sensor, and a radius of the interference pattern on the image sensor;
- and
- obtaining an offset parameter including at least one of a linearity gain used to adjust a variance amount of the wavefront aberration of the target optical system, and an absolute value used to adjust an absolute amount of the wavefront aberration of the target optical system,
- measuring the wavefront aberration of the target optical system by calculating a wavefront aberration from the detected interference pattern using the process parameter and the offset parameter.
A measurement apparatus for measuring a wavefront aberration of a target optical system by detecting an interference pattern formed by light passing through the target optical system, said measurement apparatus comprising:
- a memory configured to store a process parameter including at least one of a thickness of a member that generates the interference pattern, a distance between the member and an image sensor that takes an image of the interference pattern, a central coordinate of the interference pattern on the image sensor, and a radius of the interference pattern on the image sensor and an offset parameter including at least one of a linearity gain used to adiust a variance amount of the wavefront aberration of the target optical system, and an absolute value used to adiust an absolute amount of the wavefront aberration of the target optical system;
- and
- a processor configured to measure the wavefront aberration of the target optical system by calculating a wavefront aberration from the detected interference pattern using the process parameter and the offset parameter.
Dependencies are inferred from the claim text.