Scatterometry measurement of asymmetric structures

A method of determining asymmetry in an in-chip structure on a semiconductor wafer, the method comprising:

• illuminating the in-chip structure with polarized light;
• analyzing the specular light after the light interacts with the in-chip structure;
• detecting the analyzed light;
• generating with a processor at least a partial Mueller matrix using the detected light;
• fitting with the processor the Mueller matrix to at least one of a rigorous electromagnetic model of the in-chip structure and a calibrated linear response to determine the asymmetry in the in-chip structure.

An apparatus for measuring asymmetry of a structure on a sample, the apparatus comprising:

• a polarization state generator that produces polarized light to be incident on the structure;
• a polarization state detector that analyzes and detects the light after the interacts with the structure and generates signals in response to the detected light;
• a processor coupled to receive the signals from the polarization state detector;
• memory coupled to the processor;
• software held in the memory and run in the processor to generate at least a partial Mueller matrix using the signals from the polarization state detector and to fit the Mueller matrix to at least one of a rigorous electromagnetic model of the structure and a calibrated linear response to determine the asymmetry of the structure, wherein the asymmetry is determined without the use of light that is incident on and detected from a different structure.