Raman spectroscopy based measurements in patterned structures

A method for use in measuring one or more characteristics of a patterned structure, the method comprising:

• illuminating the patterned structure by an illumination channel of an optical measurement system;
• obtaining, by a detection channel of the optical measurement system, measured data indicative of at least one Raman spectrum obtained from the patterned by a detection system of the optical measurement system;
• and
• a control unit that is configured to apply model based metrology on the measured data to provide one or more characteristics of the patterned structure from the measured data;
• wherein the illuminating and the obtaining are executed while one or more affecting units of the optical measurement system affect at least one or more conditions selected out of one or more illumination conditions and one or more collection conditions, wherein the one or more illumination conditions comprise an illumination polarization parameter, and the one or more collection conditions comprise one or more variable aperture parameters;
• wherein the optical measurement system further comprises an objective lens shared by the illumination and collection channel;
• and
• wherein the illumination channel is defined by a light source system that has a variable polarization unit, the light source system comprises at least three illumination sources with different wavelengths.

A non-transitory computer readable medium for use in measuring one or more characteristics of a patterned structure, the non-transitory computer readable medium stores instructions for:

• illuminating the patterned structure by an illumination channel of an optical measurement system;
• obtaining, by a detection channel of the optical measurement system, measured data indicative of at least one Raman spectrum obtained from the patterned by a detection system of the optical measurement system;
• and
• a control unit that is configured to apply model based metrology on the measured data to provide one or more characteristics of the patterned structure from the measured data;
• wherein the illuminating and the obtaining are executed while one or more affecting units of the optical measurement system affect at least one or more conditions selected out of one or more illumination conditions and one or more collection conditions, wherein the one or more illumination conditions comprise an illumination polarization parameter, and the one or more collection conditions comprise one or more variable aperture parameters;
• wherein the optical measurement system further comprises an objective lens shared by the illumination and collection channel;
• and
• wherein the illumination channel is defined by a light source system that has a variable polarization unit, the light source system comprises at least three illumination sources with different wavelengths.