Three dimensional sidewall measurements by laser fluorescent confocal microscopy

Area of Science:

• Metrology
• Microscopy
• Surface characterization

Background:

• Conventional profiling techniques struggle with precise 3D measurements of vertical sidewalls in concave micro-structures.
• Accurate characterization of micro-scale features is crucial for various scientific and engineering applications.

Purpose of the Study:

• To introduce a simple yet effective technique for obtaining 3D sidewall geometry of concave micro-structures.
• To analyze the underlying physical principles of the proposed measurement method.
• To evaluate the strengths, limitations, and accuracy improvement factors of the technique.

Main Methods:

• Utilizes laser fluorescent confocal microscopy combined with an intensity gradient algorithm.
• Employs a fluorescent solution to fill concave micro-structures for imaging.
• Identifies the micro-structure profile based on maximum intensity variation in 3D volume images.

Main Results:

• Demonstrates capability for measuring 3D geometry of various concave features, including vertical and buried micro channels.
• Achieves sub-micrometer (RMS) measurement accuracy and repeatability.
• Provides detailed analysis of the measurement principle and influencing factors.

Conclusions:

• The developed technique offers a viable solution for precise 3D profile measurements of challenging concave micro-structures.
• It overcomes limitations of traditional methods, enabling accurate characterization of micro-scale sidewall geometry.
• The technique shows high potential for applications requiring detailed micro-structure analysis.