Generic interface for an optical metrology system

An optical metrology system, comprising:

• a processing module configured to receive a measured diffraction signal from a photometric device;
• and
• a generic interface for the processing module configured to provide the measured diffraction signal to the processing module using a standard set of signal parameters comprising:
• a reflectance parameter that characterizes the change in intensity of light when reflected on the structure wherein the reflectance parameter is an average of the square of the absolute value of complex reflection coefficients average over depolarization effects, and
• a polarization parameter that characterizes the change in polarization states of light when reflected on the structure, wherein the polarization parameter comprises:
• a first polarization parameter that characterizes half of the difference between the square of the absolute value of the complex reflection coefficients average over depolarization effects, and normalized to the reflectance parameter,
• a second polarization parameter that characterizes an imaginary component of an interference of the complex reflection coefficients average over depolarization effects, and normalized to the reflectance parameter, and
• a third polarization parameter that characterizes a real component of an interference of the complex reflection coefficients average over depolarization effects, and normalized to the reflectance parameter.

A method of analyzing a structure using an optical metrology system, comprising:

• directing light onto the structure to obtain a measured diffraction signal using a photometric device;
• processing the measured diffraction signal using a generic interface to provide the measured diffraction signal to a processing module using a standard set of signal parameters comprising:
• a reflectance parameter that characterizes the change in intensity of light when reflected on the structure, and
• a polarization parameter that characterizes the change in polarization states of light when reflected on the structure;
• and
• processing the measured diffraction signal using the processing module to analyze the structure.

A computer-readable storage medium containing computer executable instructions for causing a computer to analyze a structure using an optical metrology system, comprising instructions for:

• directing light onto the structure to obtain a measured diffraction signal using a photometric device;
• processing the measured diffraction signal using a generic interface to provide the measured diffraction signal to a processing module using a standard set of signal parameters comprising:
• a reflectance parameter that characterizes the change in intensity of light when reflected on the structure, and
• a polarization parameter that characterizes the change in polarization states of light when reflected on the structure;
• and
• processing the measured diffraction signal using the processing module to analyze the structure.