Systems for providing illumination in optical metrology

摘要

The disclosure is directed to systems for providing illumination to a measurement head for optical metrology. In some embodiments of the disclosure, illumination beams from a plurality of illumination sources are combined to deliver illumination at one or more selected wavelengths to the measurement head. In some embodiments of the disclosure, intensity and/or spatial coherence of illumination delivered to the measurement head is controlled. In some embodiments of the disclosure, illumination at one or more selected wavelengths is delivered from a broadband illumination source configured for providing illumination at a continuous range of wavelengths.

主权项

1. A system for providing illumination to a measurement head, comprising:
a plurality of illumination sources including a first illumination source, a second illumination source, a third illumination source, a fourth illumination source, a fifth illumination source, and a sixth illumination source; a first fold mirror configured to reflect illumination from the first illumination source along a guidance path; a second fold mirror configured to reflect illumination from the second illumination source along the guidance path; a first dichroic combiner configured to transmit illumination from the first illumination source along the guidance path, the first dichroic combiner further configured to reflect illumination from the third illumination source along the guidance path; a second dichroic combiner configured to transmit illumination from the second illumination source along the guidance path, the second dichroic combiner further configured to reflect illumination from the fourth illumination source along the guidance path; a third dichroic combiner configured to transmit illumination from the first illumination source and illumination from the third illumination source along the guidance path, the third dichroic combiner further configured to reflect illumination from the fifth illumination source along the guidance path; a fourth dichroic combiner configured to transmit illumination from the sixth illumination source along the guidance path; the fourth dichroic combiner further configured to reflect illumination from the second illumination source and illumination from the fourth illumination source along the guidance path; and a fifth dichroic combiner configured to transmit illumination from the second illumination source, illumination from the fourth illumination source, and illumination from the sixth illumination source along an illumination path to a measurement head, the fifth dichroic combiner further configured to reflect illumination from the first illumination source, illumination from the third illumination source, and illumination from the fifth illumination source along the illumination path to the measurement head.