Detection of In-Plane Movement in Electrically Actuated Microelectromechanical Systems Using a Scanning Electron...

Area of Science:

• MEMS technology
• Nanoscale metrology
• Electron microscopy

Background:

• Measuring in-plane motion in microelectromechanical systems (MEMS) is difficult due to device size and low motion amplitude.
• Existing techniques face limitations in characterizing nanoscale movements.

Purpose of the Study:

• To investigate the feasibility of using Scanning Electron Microscope (SEM) imaging with motion detection algorithms for MEMS motion characterization.
• To address uncertainties regarding SEM's accuracy in motion detection compared to optical methods, considering electrical actuation interference.

Main Methods:

• Utilized existing motion detection algorithms applied to SEM images.
• Analyzed the impact of electrical actuation on measurement accuracy.
• Explored image properties like bright edges for motion detection enhancement.

Main Results:

• Successfully detected motion with amplitudes as low as 69 nm using SEM and motion detection algorithms.
• SEM image features, such as bright edges, were found to complement the algorithms.
• Electrical actuation introduced measurement errors, primarily in electrically connected regions, with minimal impact on insulated areas.

Conclusions:

• SEM is a powerful tool for characterizing low-amplitude motion in MEMS.
• SEM enables motion detection below 100 nm amplitude and aids in analyzing electrical contacts within MEMS devices.
• The study validates SEM's utility despite potential interference from electrical actuation.