Imaging Scatterometry

TL;DR

This paper introduces an optical imaging scatterometry system capable of high-resolution, localized surface topography measurements of micro/nano-structures, enabling rapid, multi-area analysis with validation on nano-textured samples.

Contribution

The work presents a novel imaging scatterometer integrated into microscopes for simultaneous, high-resolution topography characterization of multiple surface segments.

Findings

Achieved nm resolution in measuring surface features.

Validated system performance on nano-textured samples.

Demonstrated multi-area imaging capability.

Abstract

We present an optical metrology system for characterization of topography of micro/nano-structures on a surface or embedded in a semi-transparent material. Based on the principles of scatterometry, where the intensity of scattered light is used as a 'fingerprint' to reconstruct a surface, this new imaging scatterometer can easily find areas of interest on the cm scale and measure multiple segments simultaneously. The imaging scatterometer measures structural features, such as height, width, and sidewall angle of a grating locally on few um2 areas with nm resolution. We demonstrate two imaging scatterometers, one built into an optical microscope and one in a split configuration. The two scatterometers are targeted characterization of mm2 and cm2 areas, respectively, and both setups are validated using nano-textured samples.