Broadband light profile microscopy: a rapid and direct method for thin film depth imaging

Area of Science:

• Materials Science and Engineering
• Optical Physics
• Surface Science

Background:

• Conventional optical inspection methods struggle to visualize subtle interface structures in thin films.
• Existing techniques often require complex sample preparation or specialized equipment.
• There is a need for direct, high-contrast imaging methods for thin film analysis.

Purpose of the Study:

• To introduce and demonstrate broadband light profile microscopy (BB-LPM) as a novel optical inspection technique.
• To showcase BB-LPM's capability for direct imaging of thin film layer structures.
• To highlight the effectiveness of BB-LPM for samples of industrial and manufacturing relevance.

Main Methods:

• Utilized a novel right-angle imaging geometry for enhanced contrast.
• Employed white-light excitation for BB-LPM, relying on elastic scatter, refraction, and transmission for contrast.
• Implemented a compact and easily aligned apparatus with minimal sample preparation requirements.

Main Results:

• Achieved outstanding contrast for subtle interface structures and morphologies, often invisible to conventional methods.
• Demonstrated BB-LPM's effectiveness in directly imaging the layered structures of various thin film samples.
• BB-LPM provided interface contrast comparable to laser-based light profile microscopy.

Conclusions:

• Broadband light profile microscopy (BB-LPM) is a viable and effective method for direct thin film imaging.
• The technique offers significant advantages in contrast and ease of use for industrial applications.
• BB-LPM provides a powerful new tool for the characterization of thin film materials.