Deep-subwavelength Nanometric Image Reconstruction using Fourier Domain Optical Normalization

Area of Science:

• Optical Metrology
• Nanotechnology
• Solid State Physics

Background:

• Accurate measurement of sub-wavelength nanometric structures is a significant challenge.
• Existing methods often lack the required precision for atomic-scale details.

Purpose of the Study:

• To develop a quantitative optical measurement approach for 3D nanometric structures.
• To achieve sub-nanometer sensitivity for features smaller than 1/30th of the wavelength.

Main Methods:

• Utilized a Fourier domain normalization approach within Fourier optical imaging code.
• Simulated the full 3D scattered light field for 15 nm structures.
• Accurately replicated the light field as a function of focus position.

Main Results:

• Successfully fitted nanometer-scale details, including a 2 nm conformal oxide and topography.
• Measured densely packed structures closer than the Rayleigh resolution limit.
• Achieved sub-nanometer parametric uncertainties for feature sizes.

Conclusions:

• The developed method enables practical measurement sensitivity to atomic-scale variations.
• Broad applications in measuring nanometric structures and nanoelectronic devices.
• Offers high throughput optical configuration for nanoscale metrology.