Light source assembly that generates heterodyne output beams

摘要

A beam adjuster assembly (14) receives an input beam (16) and provides a first output beam (18) and a spaced apart second output beam (20). The beam adjuster assembly (14) comprises a first frequency adjuster (22) and a second frequency adjuster (24). The first frequency adjuster (22) receives the input beam (16). The first frequency adjuster (22) transmits a first portion of the input beam (16) to provide the first output beam (18) having a first output frequency. Additionally, the first frequency adjuster (22) adjusts a second portion of the input beam (16) to provide a first adjusted beam (354). The second frequency adjuster (24) receives the first adjusted beam (354). Moreover, the second frequency adjuster (24) adjusts at least a portion of the first adjusted beam (354) to provide the second output beam (20) having a second output frequency that is different than the first output frequency.

主权项

1. A beam adjuster assembly for a measurement system of a lithography system for measuring displacement of a stage which retains a substrate for a lithography process of the lithography system, the beam adjuster assembly receiving an input beam and providing a first output beam and a spaced apart second output beam, the beam adjuster assembly comprising:
a first frequency adjuster that receives the input beam, the first frequency adjuster transmitting a first portion of the input beam without any change in frequency to provide the first output beam having a first output frequency, and the first frequency adjuster adjusting a frequency of a second portion of the input beam to provide a first adjusted beam; and a second frequency adjuster that receives the first adjusted beam, the second frequency adjuster adjusting the frequency of at least a portion of the first adjusted beam to provide the second output beam having a second output frequency that is different than the first output frequency.