Patent ID: 11860036
Assignee: CYMER, LLC
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An optical measurement apparatus for alight source, the optical measurement apparatus comprising:
an etalon comprising a focusing lens configured to focus light at an image plane, wherein the etalon is associated with a calibration parameter related to the focusing lens, and the calibration parameter has a pre-set default value;
an optical detector configured to detect an interference pattern produced by the etalon and to produce information related to the etalon, the information comprising first spatial information for a first fringe and second spatial information for a second fringe; and
a control system coupled to the optical detector, the control system configured to:
determine a measurement error value of the etalon based on first spatial information from the detector, the second spatial information, and an initial value of the calibration parameter; and
analyze the measurement error value to determine whether to adjust the pre-set default value.