Three-Dimensional Atomic Force Microscopy for Sidewall Imaging Using Torsional Resonance Mode.

Lu Liu,Sen Wu,Rui Zhang,Jianguo Xu,Xiaodong Hu,Xiaotang Hu

doi:10.1155/2018/7606037

Abstract

This article presents an atomic force microscopy (AFM) technique for true three-dimensional (3D) characterization. The cantilever probe with flared tip was used in a home-made 3D-AFM system. The cantilever was driven by two shaking piezoceramics and oscillated around its vertical or torsional resonance frequency. The vertical resonance mode was used for upper surface imaging, and the torsional resonance mode was used for sidewall detecting. The 3D-AFM was applied to measure standard gratings with the height of 100 nm and 200 nm. The experiment results showed that the presented 3D-AFM technique was able to detect the small defect features on the steep sidewall and to reconstruct the 3D topography of the measured structure.

Highlights

The size of electron devices continues to decrease due to the development of semiconductor technology and the use of new materials
There are still some difficulties in measuring critical dimension (CD) such as the width and sidewall, which was cited in International Technology Roadmap for Semiconductors (ITRS) as early as 2003 [5]
We present an amplitude modulation 3DAFM system for the sidewall measurement

Summary

Introduction

The size of electron devices continues to decrease due to the development of semiconductor technology and the use of new materials. There are still some difficulties in measuring critical dimension (CD) such as the width and sidewall, which was cited in International Technology Roadmap for Semiconductors (ITRS) as early as 2003 [5]. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), and optical scatterometry are the main topography measurement technologies in the semiconductor industry. Each method has its own advantages and limitations Among these measurement techniques, AFM offers direct and almost nondestructive measurements of the shape of nanostructures with both high lateral and vertical resolution. For the true 3D characterization, several groups have developed threedimensional atomic force microscopy (3D-AFM) or critical dimension atomic force microscopy (CD-AFM)

Methods

Results

Conclusion