Coherent Fourier scatterometry using orbital angular momentum beams for defect detection

Area of Science:

• Semiconductor Manufacturing
• Optical Metrology
• Nanotechnology

Background:

• Defect inspection is crucial for semiconductor quality assurance.
• Current Coherent Fourier Scatterometry (CFS) with Gaussian beams faces limitations with shrinking critical dimensions.
• Extreme ultraviolet lithography demands higher sensitivity and throughput in inspection.

Purpose of the Study:

• Introduce novel bright-field CFS techniques using orbital angular momentum (OAM) beams.
• Develop defect inspection methods with enhanced sensitivity and robustness for nanoscale features.
• Address the need for advanced in-line inspection in high-volume semiconductor manufacturing.

Main Methods:

• Utilized bright-field Coherent Fourier Scatterometry (CFS) with coherent beams carrying orbital angular momentum (OAM).
• Developed a differential OAM CFS technique that does not require pre-established databases for symmetric patterns.
• Employed numerical investigations to evaluate performance on amplitude and phase defects.

Main Results:

• Demonstrated superior performance of OAM-based CFS techniques compared to conventional Gaussian beam CFS.
• Achieved up to an order of magnitude higher signal-to-noise ratio for defect detection.
• Showcased enhanced sensitivity and robustness for in-line nanoscale defect inspection.

Conclusions:

• Novel OAM-based CFS techniques significantly improve nanoscale defect inspection sensitivity and robustness.
• Differential OAM CFS offers a unique, database-independent inspection method for symmetric structures.
• These advancements are vital for next-generation semiconductor manufacturing, particularly with extreme ultraviolet lithography.