Flexible measurement models for model based measurements of semiconductor structures

A method comprising:

• illuminating a semiconductor structure with an amount of radiation at each of one or more measurement sites;
• detecting an amount of measurement data associated with measurements of the semiconductor structure in response to the amount of radiation;
• receiving an indication of a selection of a re-useable, parametric model to describe a physical characteristic of at least a first portion of the semiconductor structure, wherein the re-useable, parametric model includes multiple geometric sections each characterized by a different shape profile parameterized by at least one shape parameter, wherein the re-useable, parametric model is fully defined by a set of independent parameters including the shape parameters characterizing the shape profiles of the multiple, geometric sections;
• receiving an indication of a selection of initial values of the shape parameters associated with the shape profiles;
• and
• estimating a value of a parameter of interest characterizing the physical characteristic of the semiconductor structure at each of the one or more measurement sites based on a fitting of a measurement model to the amount of measurement data associated with each of the one or more measurement sites, wherein the measurement model includes the re-useable, parametric model.

A metrology system comprising:

• an illumination subsystem configured to illuminate a semiconductor structure with an amount of radiation at each of one or more measurement sites;
• a detector configured to detect an amount of measurement data associated with measurements of the semiconductor structure in response to the amount of radiation;
• and
• a computing system configured to:
• receive an indication of a selection of a re-useable, parametric model to describe at least a portion of the semiconductor structure, wherein the re-useable, parametric model is fully defined by a set of independent parameter values, wherein the re-useable, parametric model describes a nanowire or nanosheet having any of a rounded square cross-section, a rounded trapazoid cross-section, a rounded diamond cross-section, and a rounded triangle cross-section;
• receive an indication of a selection of the set of independent parameter values;
• and
• estimate a value of a parameter of interest characterizing the semiconductor structure at each of the one or more measurement sites based on a fitting of a measurement model to the amount of measurement data associated with each of the one or more measurement sites, wherein the measurement model includes the re-useable, parametric model.