Parameter optimization for through-focus scanning optical microscopy.

Area of Science:

• Metrology and Nanotechnology
• Optical Physics

Background:

• Accurate 3-D shape analysis of nanoscale objects is vital for high-volume nanomanufacturing and process control.
• Through-focus scanning optical microscopy (TSOM) is a promising technique for high-throughput, non-destructive 3-D metrology.
• A systematic investigation into TSOM parameter optimization was previously lacking.

Purpose of the Study:

• To systematically study and optimize the key parameters influencing the performance of Through-focus Scanning Optical Microscopy (TSOM).
• To enhance the accuracy and efficiency of 3-D shape metrology for nanometer to micrometer scale objects.

Main Methods:

• Optimization of illumination numerical aperture (NA) and collection NA.
• Adjustment of focus step height and digital camera pixel size.
• Investigation of illumination polarization and wavelength effects on TSOM performance.

Main Results:

• Identified optimal settings for illumination NA, collection NA, focus step height, and pixel size.
• Determined the influence of illumination polarization and wavelength on measurement resolution and accuracy.
• Demonstrated peak performance of the TSOM method through systematic parameter optimization.

Conclusions:

• Systematic optimization of TSOM parameters significantly enhances its capability for precise 3-D nanoscale metrology.
• The findings provide a framework for achieving sub-nanometer measurement resolution in high-volume nanomanufacturing.
• Optimized TSOM is a viable solution for economical and non-destructive 3-D shape analysis in advanced manufacturing processes.