Metrology method and apparatus for of determining a complex-valued field
AssigneeASML Netherlands B.V.
InventorsAlexander Prasetya Konijnenberg, Willem Marie Julia Marcel Coene, Nitesh Pandey
Life of this patent
Estimating the term…
Abstract
Disclosed is a method of determining a complex-valued field relating to a sample measured using an imaging system. The method comprises obtaining image data relating to a series of images of the sample, imaged at an image plane of the imaging system, and for which at least two different modulation functions are imposed in a Fourier plane of the imaging system; and determining the complex-valued field from the imaging data based on the imposed modulation functions.
Claims14
A method, comprising:
- imaging, by an imaging system, a field reflected from a sample;
- imposing, at a Fourier plane of the imaging system, at least two different modulation functions in the reflected field;
- detecting, at an image plane of the imaging system, a series of images of the sample;
- obtaining image data relating to the series of images of the sample;
- and
- determining a complex-valued field from the image data based on the imposed modulation functions,
- wherein the at least two different modulation functions comprise a plurality of pairs of modulation functions, each of the pairs of modulation functions comprising modulation functions that differ only in a perturbation region.
A non-transitory computer readable medium comprising processor readable instructions which, when run on a processor controlled apparatus, cause the processor controlled apparatus to perform a method comprising:
- imaging a field reflected from a sample;
- imposing, at a Fourier plane of an imaging system, at least two different modulation functions in the reflected field;
- detecting, at an image plane of the imaging system, a series of images of the sample;
- obtaining image data relating to the series of images of the sample, imaged at an image plane of the imaging system, and for which at least two different modulation functions are imposed in a Fourier plane of the imaging system;
- and
- determining a complex-valued field from the image data based on the imposed modulation functions when run on a suitable apparatus,
- wherein the at least two different modulation functions comprise a plurality of pairs of modulation functions, each of the pairs of modulation functions comprising modulation functions that differ only in a perturbation region.
Dependencies are inferred from the claim text.