Simultaneous measurement method of total and self-interference for the volumetric thickness-profilometer

Area of Science:

• Optics and Photonics
• Materials Science
• Metrology

Background:

• Accurate measurement of thin film properties is crucial for microelectronics and optics.
• Existing methods often lack simultaneous measurement capabilities for total and self-interference.
• Characterizing micro-patterned thin films requires high-resolution and efficient techniques.

Purpose of the Study:

• To propose a simultaneous measurement method for total and self-interference in micro-patterned thin films.
• To develop a compact and light-efficient system for separate measurements of film thickness and surface profile.
• To demonstrate the system's efficiency for high-speed measurements.

Main Methods:

• Extension of a full-field wavelength scanning interferometer using a single acousto-optic tunable filter (AOTF).
• Utilizing polarization-sensitive diffraction in non-collinear acousto-optic interaction to separate signals.
• Employing manipulated polarization states of reference and sample light for simultaneous signal generation in different directions.
• Integration of a beam splitter and two CCDs for data acquisition.

Main Results:

• Simultaneous measurement of total interference and self-interference achieved.
• Separate determination of thickness and surface profile for micro-patterned thin films.
• Realization of a compact and light-efficient system with 2-4 times higher light-efficiency than previous systems.
• Experimental results validated against commercial equipment, showing high-speed measurement capability.

Conclusions:

• The proposed method enables simultaneous, separate measurements of thin film thickness and surface profile.
• The developed system offers a compact, light-efficient, and high-speed solution for micro-patterned thin film analysis.
• This technique provides an efficient alternative for metrology applications in microfabrication and material science.