Note: Near infrared interferometric silicon wafer metrology

Area of Science:

• Semiconductor Manufacturing
• Optical Metrology
• Materials Science

Background:

• Accurate characterization of silicon wafers is critical for semiconductor device fabrication.
• Traditional metrology techniques may have limitations in non-destructively measuring wafer properties.
• Near-infrared (NIR) light offers unique advantages due to its transparency through silicon.

Purpose of the Study:

• To present and validate two novel NIR interferometric techniques for silicon wafer metrology.
• To demonstrate the capability of these methods for precise wafer characterization.
• To advance non-contact, high-resolution wafer inspection.

Main Methods:

• Fiber-based spectrally resolved interferometry for optical thickness measurement.
• Stitching low-coherence scanning interferometry for full wafer surface reconstruction.
• Experimental verification using silicon wafer samples.

Main Results:

• Successfully measured the optical thickness of silicon wafers using spectrally resolved interferometry.
• Reconstructed complete wafer surfaces with high resolution using stitching interferometry.
• Validated the accuracy and reliability of both techniques through experimental data.

Conclusions:

• The described NIR interferometric techniques provide effective solutions for silicon wafer metrology.
• These methods offer high precision for optical thickness and surface profiling.
• The study contributes advanced tools for quality control in semiconductor production.