Method for correcting measurements in the manufacture of integrated circuits and associated apparatuses
Disclosed is a method of metrology. The method comprises illuminating a radiation onto a substrate; obtaining measurement data relating to at least one measurement of each of one or more structures on the substrate; using a Fourier-related transform to transform the measurement data into a transformed measurement data; and extracting a feature of the substrate from the transformed measurement data, or eliminating an impact of a nuisance parameter.
1 . A method of metrology comprising:
illuminating radiation onto a substrate, the radiation having a wavelength that is greater than or equal to 0.1 nm and less than or equal to 100 nm;
obtaining measurement data relating to at least one measurement of each of one or more structures on the substrate;
using a Fourier-related transform to transform the measurement data into a transformed measurement data, the transformed measurement data comprising a depth spectrum; and
extracting a feature of the substrate from the transformed measurement data or eliminating an impact of a nuisance parameter.
2 . The method of claim 1 , wherein the extracting a feature of the substrate from the transformed measurement data or eliminating an impact of a nuisance parameter comprises:
determining a reconstruction signal from the transformed measurement data; and
determining one or more positional and/or size parameters of the one or more structures from the reconstruction signal.
3 . The method of claim 2 , wherein:
the reconstruction signal comprises regions of higher amplitude; and
the determining one or more positional and/or size parameters comprises determining these parameters from the size and/or position and/or a configuration of a corresponding one or more of the regions of higher amplitude.
4 . The method of claim 3 , wherein the size and/or position and/or a configuration of the regions of higher amplitude corresponding to a second and/or third direction parallel to a substrate plane is indicative of the one or more of the positional and/or size parameters in the second and/or third direction.
5 . The method of claim 2 , wherein the reconstruction signal comprises a combination of results from multiple measurements using different illumination spectra on the same one or more structures.
6 . The method of claim 1 , wherein the extracting a feature of the substrate from the transformed measurement data or eliminating an impact of a nuisance parameter comprises determining a position of a peak value in the transformed measurement data and extracting a feature of the substrate from the position of the peak value.
7 . The method of claim 1 , wherein the using a Fourier-related transform to transform the measurement data into transformed measurement data comprises transforming the measurement data from a reciprocal space to a real space.
8 . The method of claim 7 , wherein the transforming the measurement data into transformed measurement data comprises a Fourier transform.
9 . The method of claim 7 , further comprising transforming the transformed measurement data back to the reciprocal space.
10 . The method of claim 1 , wherein the extracting a feature of the substrate from the transformed measurement data or eliminating an impact of a nuisance parameter comprises applying a bandpass filter to the transformed measurement data.
11 . The method of claim 1 , further comprising a weighting step using a weighting function.
12 . The method of claim 1 , wherein the obtaining the measurement data relating to at least one measurement of each of one or more structures on the substrate comprises obtaining a diffraction pattern from a target structure comprising at least two differently biased targets.
13 . The method of claim 1 , wherein the method is an iterative method.
14 . The method of claim 1 , wherein the method is a non-iterative method.
15 . The method of claim 1 , wherein the method comprises a data-driven step or training a model.
16 . The method of claim 1 , wherein the measurement data comprises at least an asymmetry or symmetry component of the measurement data describing an asymmetry in the one or more structures.
17 . The method of claim 1 , wherein the measurement data comprises diffraction efficiencies or diffraction intensities or relates to any amplitude metric for a plurality of diffraction orders.
18 . The method of claim 1 , wherein the Fourier-related transform is performed to obtain a complex-valued spectrum for the one or more structures in distance space.
19 . The method of claim 1 , further comprising performing the transforming the measurement data to cover three dimensions of the one or more structures.
20 . The method of claim 1 , wherein the obtaining measurement data comprises obtaining the measurement data in pupil space.
21 . A non-transitory computer program product comprising machine-readable instructions therein, the instructions, upon execution by a computer system, configured to cause the computer system to at least cause performance of a method of metrology comprising:
illuminating radiation onto a substrate, the radiation having a wavelength that is greater than or equal to 0.1 nm and less than or equal to 100 nm;
obtaining measurement data relating to at least one measurement of each of one or more structures on the substrate;
using a Fourier-related transform to transform the measurement data into a transformed measurement data, the transformed measurement data comprising a depth spectrum; and
extracting a feature of the substrate from the transformed measurement data or eliminating an impact of a nuisance parameter.
22 . A metrology apparatus comprising:
a controller configured to:
illuminate radiation onto a substrate, the radiation having a wavelength that is greater than or equal to 0.1 nm and less than or equal to 100 nm;
obtain a measurement data relating to at least one measurement of each of one or more structures on the substrate;
use a Fourier-related transform to transform the measurement data into a transformed measurement data, the transformed measurement data comprising a depth spectrum; and
extract a feature of the substrate from the transformed measurement data or eliminating an impact of a nuisance parameter.