Spatially Resolved Spectroscopic Extreme Ultraviolet Reflectometry for Laboratory Applications

Area of Science:

• Materials Science
• Surface Science
• Metrology

Background:

• Characterizing thin, non-uniform contamination layers on semiconductor wafers is crucial for quality control.
• Existing methods may lack the spatial resolution or chemical sensitivity required for localized defect analysis.

Purpose of the Study:

• To develop and demonstrate a spatially resolved extreme ultraviolet (EUV) reflectometry technique for local characterization of thin contamination layers.
• To assess the chemical sensitivity and spatial resolution capabilities of the developed EUV reflectometry method.

Main Methods:

• Developed a laboratory tool for multi-angle (2°-15°) and spectrally broadband (9.5-17 nm) EUV reflectometry at grazing incidence.
• Achieved a minimum EUV spot size of 25×30 μm in the sample plane for high spatial resolution.
• Performed sample reflectivity mapping to analyze contamination layers.

Main Results:

• Demonstrated high chemical sensitivity of the EUV reflectometry technique for contaminant detection.
• Successfully identified amorphous aluminum oxide (Al₂O₃) and carbon as contaminants on a silicon wafer.
• Correlated the EUV reflectometry results with those obtained by energy-filtering photoemission electron microscopy.

Conclusions:

• Spatially resolved EUV reflectometry is an effective method for local characterization of thin, non-uniform contamination layers.
• The developed laboratory tool provides a powerful approach for metrology in semiconductor manufacturing and materials analysis.
• The technique offers high chemical sensitivity and spatial resolution for identifying critical contaminants.