Metrology Method and Apparatus, Lithographic Apparatus, and Device Manufacturing Method

摘要

A metrology apparatus includes first (21) and second (22) radiation sources which generate first (iB1) and second (iB2) illumination beams of different spatial extent and/or angular range. One of the illumination beams is selected, e.g. according to the size of target to be measured. The beam selection can be made by a tillable mirror (254) at a back-projected substrate plane in a Kohler illumination setup.

主权项

1. A system comprising:
first and second sources configured to emit corresponding first and second beams of radiation; a beam selection device comprising a tiltable mirror configured to be tiltable about two axes, wherein:
the tiltable mirror is positioned such that the first beam of radiation is incident on the tiltable mirror at a first angle of incidence and the second beam is incident on the tiltable mirror at a second angle of incidence, andthe beam selection device is configured to select one of the first and second beams of radiation as a measurement beam of radiation by tilting the tiltable mirror; an objective lens configured to direct the measurement beam of radiation onto the target on the substrate and to collect radiation diffracted by the target; and a sensor configured to detect an angle resolved spectrum in a pupil plane of the objective lens.