Spectroscopic measurement system using an off-axis spherical mirror and refractive elements

A method for performing spectroscopic ellipsometry scatterometric measurements on a sample having diffracting structures thereon, comprising:

• providing broadband radiation from a source;
• focusing broadband radiation from the source in a sampling beam to a spot on the sample by means of optics that includes a curved mirror;
• polarizing broadband radiation that is from the source and that is focused by the optics to the spot on the sample;
• analyzing radiation from the sampling beam that has interacted with the sample by means of an analyzer, thereby producing an output beam;
• detecting the output beam to provide a detected output;
• and
• processing the detected output to determine changes of polarization state in amplitude and phase of the sampling beam caused by interaction with the sample in order to measure parameters of the diffracting structure.

An ellipsometer for performing spectroscopic scatterometric measurements on a sample having diffracting structures thereon, comprising:

• a source which emits broadband radiation;
• optics including at least one refractive element, said optics focusing broadband radiation from the source in a sampling beam to a spot on the diffracting structures of the sample;
• a polarizer that polarizes broadband radiation that is from the source and that is focused by the optics to the spot on the sample;
• an analyzer that analyses radiation from the sampling beam that has interacted with the sample, thereby producing an output beam, wherein radiation reaching the analyzer from the source travels along an optical path;
• a detector detecting the output beam to provide an output;
• and
• a processor processing the detector output to determine changes of polarization state in amplitude and phase of the sampling beam caused by interaction with the sample in order to measure parameters of the diffracting structure.

A method for performing spectroscopic ellipsometry scatterometric measurements on a sample having diffracting structures thereon, comprising:

• providing broadband radiation from a source;
• focusing broadband radiation from the source in a sampling beam to a spot on the sample by means of optics that includes at least one refractive element;
• polarizing broadband radiation that is from the source and that is focused by the optics to the spot on the sample;
• analyzing radiation from the sampling beam that has interacted with the sample by means of an analyzer, thereby producing an output beam;
• detecting the output beam to provide a detected output;
• and
• processing the detected output to determine changes of polarization state in amplitude and phase of the sampling beam caused by interaction with the sample in order to measure parameters of the diffracting structure.