Dual-Probe Atomic Force Microscopy based on tuning fork probes for critical dimension metrology

Zhiyue Zheng; Sitian Gao; Wei Li; Xiaojun Liu; Yushu Shi; Cheng Chen

doi:10.1016/j.ultramic.2020.113120

Dual-Probe Atomic Force Microscopy based on tuning fork probes for critical dimension metrology

Ultramicroscopy. 2020 Dec:219:113120. doi: 10.1016/j.ultramic.2020.113120. Epub 2020 Sep 19.

Authors

Zhiyue Zheng¹, Sitian Gao², Wei Li³, Xiaojun Liu⁴, Yushu Shi⁵, Cheng Chen⁶

Affiliations

¹ State Key Laboratory of Digital Manufacturing Equipment and Technology, Department of Instrument Science and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China; National Institute of Metrology, Beijing 100029, China. Electronic address: zhengzhiyue@hust.edu.cn.
² National Institute of Metrology, Beijing 100029, China. Electronic address: gaost@nim.ac.cn.
³ National Institute of Metrology, Beijing 100029, China. Electronic address: liwei@nim.ac.cn.
⁴ State Key Laboratory of Digital Manufacturing Equipment and Technology, Department of Instrument Science and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China. Electronic address: mexjl@hust.edu.cn.
⁵ National Institute of Metrology, Beijing 100029, China. Electronic address: shiys@nim.ac.cn.
⁶ State Key Laboratory of Digital Manufacturing Equipment and Technology, Department of Instrument Science and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China. Electronic address: chengchen2016@gmail.com.

PMID: 32977060
DOI: 10.1016/j.ultramic.2020.113120

Abstract

Atomic force microscopy (AFM) is widely used for nano-dimensional metrology in semiconductor manufacturing and metrological system. However, the conventional AFM can't provide accurate CD characterization of nanostructures, due to its top-down configuration and probe-size effect. In this paper, we develop a dual-probe atomic force microscopy (DPAFM). Compared to conventional optical-lever based AFM, the DPAFM exploits two tuning fork probes that simplifies significantly the setup and can be controlled based on frequency-modulation (FM) mode. The developed DPFAM is implemented that builds a zero-reference point by dual-probe alignment firstly, following which, characterizes nanostructures from two sides independently with the two probes. The final CD feature is determined by matching profiles from the two probes based on the zero-reference point. The capability of the DPAFM is validated by experiments on a CD-standard structure, that achieves the true CD assessment with good accuracy and repeatability.

Keywords: Atomic force microscope; Critical dimension metrology; Dual-probe; Tuning fork probe.