Determining tilt angle of substrate structures utilizing angular fourier decomposition of scattering images

A system, comprising memory and a processing device coupled to the memory, wherein the processing device is configured to:

• receive a first small angle scattering image of a substrate, wherein the substrate comprises a plurality of structures oriented at a first angle relative to a base of the substrate, and wherein the first small angle scattering image of the substrate is collected at a second angle of incidence of radiation relative to the base of the substrate, different than the first angle;
• determine a first first-order Fourier term associated with the first small angle scattering image by performing angular Fourier decomposition of the first small angle scattering image;
• determine a first second-order Fourier term by performing angular Fourier decomposition of the first small angle scattering image;
• and
• determine a value of the first angle based on the first first-order Fourier term and the first second-order Fourier term.

A non-transitory machine-readable storage medium storing instructions which, when executed, cause a processing device to perform operations comprising:

• receiving a first small angle scattering image of a substrate, wherein the substrate comprises a plurality of structures oriented at a first angle relative to a base of the substrate, and wherein the first small angle scattering image of the substrate is collected at a second angle of incidence of radiation relative to the base of the substrate, different than the first angle;
• determining a first first-order Fourier term associated with the first small angle scattering image by performing angular Fourier decomposition of the first small angle scattering image;
• determining, by the processing device, a first second-order Fourier term by performing angular Fourier decomposition of the first small angle scattering image;
• and
• determining, by the processing device, a value of the first angle based on the first first-order Fourier term and the first second-order Fourier term.