Surface topography acquisition method for double-sided near-right-angle structured surfaces based on dual-probe...

Area of Science:

• Metrology and Surface Science
• Optical Interferometry
• Nanotechnology and Precision Engineering

Background:

• Accurate measurement of complex micro/nanostructures is crucial for advanced manufacturing and scientific research.
• Existing methods often struggle with double-sided or near-right-angle geometries, limiting characterization capabilities.
• The development of high-resolution, non-contact metrology techniques is an ongoing challenge.

Purpose of the Study:

• To propose and validate a novel dual-probe wavelength scanning interferometry (DPWSI) approach for measuring double-sided near-right-angle structured surfaces.
• To establish a robust calibration procedure for the DPWSI system, ensuring accurate spatial and vertical measurements.
• To demonstrate the system's capability for high-resolution surface topography acquisition.

Main Methods:

• Development of the principle and mathematical model for dual-probe wavelength scanning interferometry (DPWSI).
• Calibration of the measurement system using standard step-height samples and a custom-designed artifact.
• Integration of white light scanning interferometry (WLSI) and scanning electron microscopy (SEM) for artifact topography reference.
• Application of a 3D registration algorithm to determine the precise relative probe locations.

Main Results:

• Successful calibration of the DPWSI system for both vertical measurements and spatial coordinate relationships.
• Accurate determination of the dual-probe system's relative positioning using 3D registration.
• Experimental validation demonstrating the capability to measure double-sided near-right-angle structured surfaces.
• Achieved nanometer-level vertical resolution and micrometer-level lateral resolution in measurements.

Conclusions:

• The proposed DPWSI method offers a viable solution for metrology of challenging double-sided near-right-angle structured surfaces.
• The comprehensive calibration strategy ensures high accuracy and reliability of the measurement system.
• This technique advances the field of surface metrology, enabling detailed characterization of complex geometries with high precision.