Dual-Probe Atomic Force Microscopy based on tuning fork probes for critical dimension metrology

Area of Science:

• Materials Science
• Nanotechnology
• Metrology

Background:

• Conventional atomic force microscopy (AFM) faces challenges in accurate nanostructure critical dimension (CD) characterization due to its top-down configuration and probe-size limitations.
• Existing AFM methods struggle with precise metrology in semiconductor manufacturing.

Purpose of the Study:

• To develop and validate a novel Dual-Probe Atomic Force Microscopy (DPAFM) system for accurate CD metrology.
• To overcome the limitations of conventional AFM in characterizing nanostructures.

Main Methods:

• The DPAFM system utilizes two tuning fork probes, simplifying the setup and enabling frequency-modulation (FM) mode control.
• A zero-reference point is established through dual-probe alignment, allowing independent characterization from two sides.
• Final CD features are determined by matching profiles obtained from both probes relative to the zero-reference point.

Main Results:

• Experimental validation on a CD-standard structure demonstrated the DPAFM's capability for true CD assessment.
• The developed DPAFM achieved good accuracy and repeatability in nanostructure characterization.
• The DPAFM system offers a significant improvement over conventional AFM for critical dimension measurements.

Conclusions:

• The DPAFM provides an accurate and repeatable method for nanostructure CD metrology.
• This technique addresses key limitations of conventional AFM, enhancing its utility in semiconductor manufacturing.
• DPAFM represents a significant advancement in high-precision nanoscale measurement.