Automatic determination of fourier harmonic order for computation of spectral information for diffraction structures

A non-transitory machine-accessible storage medium having instructions stored thereon which when executed cause a data processing system to perform a method automatic determination of Fourier harmonic order for computation of spectral information of diffraction structures, the method comprising:

• determining a Fourier harmonic order for computation of spectral information for periodic diffraction structures of a target structure, wherein the determination of the Fourier harmonic order is based at least in part on:
• pitches in each of a plurality of directions of the periodic structures,
• material properties of materials of the periodic structures, and
• characteristics of the periodic structures;
• computing the spectral information for the periodic structures based at least in part on the determined Fourier harmonic order;
• generating a model of the periodic structures for optical metrology measurement utilizing the computed spectral information, wherein the generated model comprises at least one grating structure that runs along at least one direction of the periodic structures and that is on top of at least one substrate;
• and
• performing optical metrology of the target structure with an optical metrology system to measure at least one parameter of the target structure using the generated model of the periodic structures.

A system comprising:

• a processor;
• and
• memory having instructions stored therein which when executed by the processor cause the system to
• determine a Fourier harmonic order for computation of spectral information for diffraction structures of a target structure, wherein the determination of the Fourier harmonic is based at least in part on:
• pitches in each of a plurality of directions of the periodic structures,
• material properties of materials of the periodic structures, and
• characteristics of the periodic structures;
• and
• compute the spectral information for the periodic structures based at least in part on the determined Fourier harmonic order,
• generate a model of the periodic structures for optical metrology measurement utilizing the computed spectral information, wherein the generated model comprises at least one grating structure that runs along at least one direction of the periodic structures and that is on top of at least one substrate;
• and
• perform optical metrology of the target structure with an optical metrology system to measure at least one parameter of the target structure using the generated model of the periodic structures.