High-Efficiency and Reliable Value Geometric Standard: Integrated Periodic Structure Reference Materials

Area of Science:

• Metrology and Instrumentation
• Materials Science
• Nanofabrication

Background:

• Integrated periodic structures are vital for calibrating optical instruments and micro-CT.
• Existing reference materials have limitations in measurement range, pattern diversity, and calibration parameters.

Purpose of the Study:

• To develop advanced integrated periodic structure reference materials with enhanced calibration features.
• To overcome limitations of current reference materials for optical and micro-CT calibration.

Main Methods:

• Fabrication using photolithography and inductively coupled plasma (ICP) etching.
• MATLAB simulations to analyze structure-morphology changes during ICP etching.
• Image processing and Fast Fourier Transform (FFT) for metrological analysis.

Main Results:

• Achieved precise control over line widths (relative error ≤ 17.5%) and periods (relative error ≤ 1.5%).
• Controlled etching depths from 30 to 60 μm for various grid line widths.
• Demonstrated high side wall verticality (90° ± 0.8°, relative error < 0.9%).

Conclusions:

• Developed versatile reference materials for high-efficiency, multi-value calibration.
• The new materials significantly improve calibration accuracy and range for optical instruments and micro-CT.
• Successfully addressed limitations of existing periodic structure reference materials.