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US 2015/0308895 A1Published application
Metrology Method and Apparatus, Lithographic Apparatus, and Device Manufacturing Method
AssigneeASML Netherlands B.V.
InventorArie Jeffrey Den Boef
Life of this patent
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Abstract
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.
Claims20
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, and
- the 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.
4 more elements
A system comprising:
- an illumination optical system arranged to illuminate a pattern;
- a projection optical system arranged to project an image of the pattern onto a substrate;
- and
- a metrology device configured to measure a property of a target on the substrate, the metrology device comprising:
- a first source configured to emit a first beam of radiation;
- a second source configured to emit a second beam 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 illumination beam is incident on the tiltable mirror at a second angle of incidence and wherein the beam selection device is configured to select one of the first and second illumination 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.
7 more elements
A method of measuring a property of a target on a substrate, the method comprising:
- generating first and second illumination beams, the first and second illumination beams differing in at least one of spatial extent and range of angles, the first and second beams being incident on a mirror configured to be tiltable about two axes, wherein the first beam of radiation is incident on the mirror at a first angle of incidence and the second illumination beam is incident on the mirror at a second angle of incidence;
- tilting the mirror such that one of the first and second illumination beams is directed onto the target;
- collecting radiation diffracted from the target using an objective lens;
- and
- detecting an angle-resolved spectrum in a pupil plane of the objective lens.
2 more elements
Dependencies are inferred from the claim text.