Atomic force microscopy based micro and nano sidewall imaging

Abstract

In the semiconductor industry, micro and nano sidewall structures imaging has high importance for nanomechanical characterization, critical dimension (CD) metrology and fabrication process optimization. Various tools and techniques are used for this purpose e.g. scatterometry, CD-scanning electron microscope, small angle X-ray scattering and atomic force microscope (AFM). Due to its important traits such as high spatial resolution and non-destructive nature, AFM has emerged as an important sidewall structures imaging tool. In this chapter, we will cover AFM-based imaging of micro and nano sidewalls. Conventional AFM has limitations in imaging sidewalls due to the top-down scanning approach. Over the years, several AFM methods have been developed to access the sidewall which includes imaging with shaped AFM probes, tilt-scanning, dual-probe AFM, orthogonal scanning and specialized AFM methods. In addition, the recently developed orthogonal probing sidewall imaging technique has ushered its importance in nanomaterial characterization on the sidewalls while obtaining force–distance curves on the micro and nano sidewalls.