Unprecedented atomic surface of silicon induced by environmentally friendly chemical mechanical polishing

Xiangxiang Cui; Zhenyu Zhang; Shiqiang Yu; Xin Chen; Chunjing Shi; Hongxiu Zhou; Fanning Meng; Jiaxin Yu; Wei Wen

doi:10.1039/d3nr01149f

Unprecedented atomic surface of silicon induced by environmentally friendly chemical mechanical polishing

Nanoscale. 2023 Jun 1;15(21):9304-9314. doi: 10.1039/d3nr01149f.

Authors

Xiangxiang Cui¹, Zhenyu Zhang¹, Shiqiang Yu², Xin Chen³, Chunjing Shi⁴, Hongxiu Zhou⁵, Fanning Meng⁴, Jiaxin Yu⁶, Wei Wen⁷

Affiliations

¹ State Key Laboratory of High-Performance Precision Manufacturing, Dalian University of Technology, Dalian 116024, China. zzy@dlut.edu.cn.
² Yunnan Academy of Macroeconomic Research (Yunnan Academy of Industrial Research), Kunming 650051, China.
³ Dayou Science and Technology Corporation, Beijing 100089, China.
⁴ School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
⁵ School of Energy and Power Engineering, Dalian University of Technology, Dalian 116024, China.
⁶ School of Manufacturing Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
⁷ College of Mechanical and Electrical Engineering, Hainan University, Haikou 570228, China.

PMID: 37171082
DOI: 10.1039/d3nr01149f

Abstract

Silicon (Si) dominates the integrated circuit (IC), semiconductor, and microelectronic industries. However, it is a challenge to achieve a sub-angstrom surface of Si. Chemical mechanical polishing (CMP) is widely used in the manufacturing of Si, while toxic and polluted slurries are usually employed in CMP, resulting in pollution to the environment. In this study, a novel environmentally friendly CMP was developed, in which a slurry is composed of ceria, hydrogen peroxide, sodium pyrophosphate, sodium carboxymethyl cellulose, sodium carbonate, and deionized water. After CMP, the surface roughness Sa was 0.067 nm with a measurement area of 50 × 50 μm², and a sub-angstrom surface is achieved. To the best of our knowledge, it is the lowest surface roughness in such a large area. Transmission electron microscopy shows that the thickness of the damaged layer after CMP is 2.8 nm. X-ray photoelectron spectroscopy and infrared Fourier transformation reveal that during CMP, a redox reaction firstly took place between Ce³⁺ and Ce⁴⁺. Si and ceria are hydroxylated, forming Si-OH and Ce-OH, then dehydration and condensation occur, generating Si-O-Ce. These findings propose new insights to fabricate a sub-angstrom surface of Si for use in IC, semiconductor, and microelectronic industries.