Imaging scatterometry for flexible measurements of patterned areas

Area of Science:

• Surface science
• Optical metrology
• Nanotechnology

Background:

• Traditional scanning probe and electron microscopy for micro/nano-textured surface characterization are time-consuming.
• Scatterometry is a faster, robust method using scattered light intensity as a surface fingerprint.
• Existing scatterometry methods typically average signals over the light source's spot size, limiting spatial resolution.

Purpose of the Study:

• To introduce and demonstrate imaging scatterometry for localized topographic parameter measurement of gratings.
• To achieve nm accuracy on surface areas as small as a few µm².
• To develop systems capable of analyzing larger areas (mm² to cm²) and multiple segments simultaneously.

Main Methods:

• Development of an imaging scatterometry technique.
• Integration of imaging scatterometry into an optical microscope setup.
• Creation of a split-configuration imaging scatterometer.
• Validation using nano-textured samples.

Main Results:

• Demonstrated localized measurement of topographic parameters with nm accuracy on micro/nano-textured surfaces.
• Showcased the ability to analyze areas down to a few µm².
• Validated the capability of imaging scatterometers to cover mm² and cm² areas, measuring multiple segments simultaneously.

Conclusions:

• Imaging scatterometry provides a significant advancement in the rapid, high-accuracy characterization of micro/nano-textured surfaces.
• The developed systems are versatile, suitable for both small-scale (µm²) and large-scale (cm²) analyses.
• This technique overcomes the spatial averaging limitations of conventional scatterometry.