Novel 3D SEM Moiré method for micro height measurement.

Area of Science:

• Materials Science
• Metrology
• Nanotechnology

Background:

• Accurate 3D shape measurement is crucial for nanoscale applications.
• Existing methods may lack the required sensitivity or resolution.
• Scanning Electron Microscopy (SEM) offers high magnification but typically provides 2D imaging.

Purpose of the Study:

• To introduce and validate a new 3D Scanning Electron Microscope Moiré Method (SMM) for high-sensitivity 3D shape measurement.
• To establish the theoretical geometric model for the 3D SMM.
• To demonstrate the method's capability for nanoscale height measurement.

Main Methods:

• Development of a theoretical geometric model for 3D SMM by integrating stereovision in SEM with in-plane SMM principles.
• Analysis of Virtual Projection Fringe (VPF) patterns under varying conditions for 3D reconstruction.
• Experimental validation using two representative applications.

Main Results:

• Successful theoretical establishment of the 3D SMM geometric model.
• Experimental validation demonstrating height measurement sensitivity below 10nm.
• Close agreement between experimental results and the proposed theoretical model.

Conclusions:

• The 3D SEM Moiré Method (SMM) is a viable technique for high-precision 3D shape measurement at the nanoscale.
• The developed theoretical model accurately predicts the performance of the 3D SMM.
• The method shows significant potential for applications requiring nano-scale metrology.