Multiple parametric nanoscale measurements with high sensitivity based on through-focus scanning optical microscopy

Area of Science:

• Optical Microscopy
• Nanoscale Metrology
• Optical Engineering

Background:

• Through-focus scanning optical microscopy (TSOM) is valuable for nanoscale measurement but is susceptible to optical and mechanical noise.
• Existing TSOM methods face challenges in sensitivity and application for comprehensive 3D parameter extraction.

Purpose of the Study:

• To investigate the sensitivity and applicability of TSOM for three-dimensional (3D) multiple parameter measurement.
• To develop and validate a robust TSOM system and simulation algorithm capable of overcoming noise interference.

Main Methods:

• A novel TSOM system utilizing objective scanning and a corresponding simulation algorithm were developed.
• Experimental validation was performed on an isolated gold (Au) line, establishing a matching library.
• 3D multiple parameters were extracted by comparing experimental and simulated TSOM images.

Main Results:

• The proposed TSOM system demonstrated robustness against optical and mechanical noises.
• Precise 3D multiple parameter results were successfully extracted for the gold line.
• Fidelity tests confirmed the system's accuracy for through-focus image analysis.

Conclusions:

• The developed TSOM system offers enhanced sensitivity and reliability for 3D nanoscale measurements.
• The system's noise robustness makes it suitable for high-volume nanomanufacturing.
• This advancement facilitates more accurate and efficient nanoscale metrology.