Measurement of surface features beyond the diffraction limit with an imaging ellipsometer
Optics Letters
|November 17, 2007
Summary
A new imaging ellipsometer technique precisely measures subwavelength structures. This method accurately determines linewidths down to 100 nm, overcoming optical resolution limits.
Area of Science:
- Optics and Photonics
- Metrology
- Nanotechnology
Background:
- Accurate measurement of subwavelength structures is crucial for advanced manufacturing and scientific research.
- Traditional optical microscopy is limited by diffraction, hindering precise feature size determination at the nanoscale.
- Existing metrology techniques may lack sensitivity or require complex instrumentation.
Purpose of the Study:
- To develop a sensitive surface and feature measurement technique for subwavelength structures.
- To utilize polarization signatures from unresolved features for linewidth measurement.
- To overcome the diffraction-limited resolution of imaging systems.
Main Methods:
- Development of a novel imaging ellipsometer.
- Utilization of polarization signatures from unresolved subwavelength structures.
- Application of a focused beam rigorous coupled wave analysis (RCWA) method for simulation.
- Experimental validation of the technique.
Main Results:
- Demonstrated accurate linewidth measurement down to 100 nm.
- Achieved measurement accuracy of approximately 10 nm for lines wider than 100 nm.
- Successfully measured features beyond the diffraction-limited resolution (500 nm) of the imaging system.
Conclusions:
- The novel imaging ellipsometer technique offers high sensitivity and accuracy for subwavelength feature metrology.
- Polarization signatures provide a powerful means to measure linewidths below the optical resolution limit.
- This technique enables precise characterization of nanoscale features, advancing semiconductor inspection and nanotechnology.
