Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization

Area of Science:

• Optics and Photonics
• Micro-electro-mechanical-systems (MEMS)
• Metrology

Background:

• Micro-electro-mechanical-systems (MEMS) are crucial components across diverse industries, necessitating robust inspection and characterization metrology systems.
• Ensuring the functional reliability of MEMS requires advanced metrology tools for precise evaluation.
• Digital holography has emerged as a powerful technique for quantitative phase retrieval and object characterization.

Purpose of the Study:

• To present a compact, lens-less digital holographic microscope (CDHM) system for micro-electro-mechanical-system (MEMS) metrology.
• To demonstrate the CDHM's capability in evaluating key characteristics for MEMS inspection.
• To validate the accuracy of the CDHM by comparing its measurements with Atomic Force Microscopy (AFM).

Main Methods:

• Development of a novel, compact digital holographic microscope (CDHM) system.
• Utilizing digital holography principles to record interference patterns between object and reference beams.
• Acquiring quantitative phase information to reconstruct surface profiles of MEMS devices.

Main Results:

• The CDHM system successfully measured surface profiles of MEMS under both static and dynamic conditions.
• Demonstrated the system's potential for evaluating critical MEMS inspection criteria.
• Initial comparisons with Atomic Force Microscopy (AFM) indicate high accuracy for the CDHM.

Conclusions:

• The lens-less CDHM presents a compact and effective solution for micro-electro-mechanical-system (MEMS) metrology.
• This technology holds significant promise for reliable industrial inspection and characterization of MEMS.
• The CDHM offers a viable alternative to existing metrology systems, potentially improving production line efficiency.