A Reflected-Light-Mode Multiwavelength Interferometer for Measurement of Step Height Standards

Area of Science:

• Metrology
• Optical Physics
• Interferometry

Background:

• Accurate measurement of step height standards is crucial for nanotechnology and semiconductor manufacturing.
• Traditional interferometry methods for step height measurement can be limited by fringe analysis techniques.

Purpose of the Study:

• To present a novel application of the variable wavelength interferometer (VAWI) for precise step height standard measurements.
• To introduce a new method for analyzing interference patterns by focusing on fringe periods and phases.
• To evaluate the metrological potential of this enhanced VAWI technique.

Main Methods:

• Utilizing a modified variable wavelength interferometer (VAWI) in reflected-light mode.
• Employing two Wollaston prisms to generate interference patterns.
• Replacing traditional fringe coincidence searching with continuous measurement of fringe periods and phases relative to the zero-order fringe.
• Analyzing the resulting sinusoidal data using both classical and uniform thickness criterion methods.

Main Results:

• The developed VAWI method provides a continuous measurement approach for step height standards.
• Simulations and experimental results demonstrate the feasibility and accuracy of the proposed technique.
• The new analysis method shows promise for enhanced metrological capabilities in step height measurements.

Conclusions:

• The modified VAWI technology offers a precise and potentially more efficient method for measuring step height standards.
• The continuous fringe analysis represents a significant advancement over traditional methods.
• Further exploration of VAWI's metrological potential is warranted for advanced applications.