Beam scanning coherent Fourier scatterometry

Abstract

The significance of precise metrology in various industries, particularly within manufacturing plants, is undeniable, especially as components and devices continue to undergo miniaturization. The emergence of nano-manufacturing further amplifies the necessity for meticulous measurement techniques. Coherent Fourier scatterometry (CFS) is a nonimaging, model-based, bright-field optical metrology and inspection technique used for retrieving complex geometric parameters of nanostructures and for detecting isolated nanoparticles and contamination on surfaces. It uses a focused light spot to illuminate the sample and the scattered light is collected as the sample is scanned in the lateral direction. However, the time it takes to inspect a certain area has been a limiting factor in its wider adoption as a commercial metrology tool. To address this limitation, we propose a novel design of CFS utilizing a galvo mirror for faster scanning of the laser spot on the sample, offering significant improvements in scan speed.