A Study on the Sub-5 nm Nano-Step Height Reference Materials Fabricated by Atomic Layer Deposition Combined with Wet Etching.

Nano-steps, as classical nano-geometric reference materials, are very important for calibrating measurements in the semiconductor industry; therefore, controlling the height of nano-steps is critical for ensuring accurate measurements. Accordingly, in this study nano-steps with heights of 1, 2, 3 and 4 nm were fabricated with good morphology using atomic layer deposition (ALD) combined with wet etching. The roughness of the fabricated nano-steps was effectively controlled by utilizing the three-dimensional conformal ALD process. Moreover, the relationship between the surface roughness and the height was studied using a simulation-based analysis. Essentially, roughness control is crucial in fabricating nano-steps with a critical dimension of less than 5 nm. In this study, the minimum height of a nano-step that was successfully achieved by combining ALD and wet etching was 1 nm. Furthermore, the preconditions for quality assurance for a reference material and the influencing factors of the fabrication method were analyzed based on the 1 nm nano-step sample. Finally, the fabricated samples were used in time-dependent experiments to verify the optimal stability of the nano-steps as reference materials. This research is instructive to fabricate nano-geometric reference materials to within 5 nm in height, and the proposed method can be easily employed to manufacture wafer-sized step height reference materials, thus enabling its large-scale industrial application for in-line calibration in integrated circuit production lines.

Citation

Chenying Wang, Lei Li, Weixuan Jing, Yaxin Zhang, Song Wang, Qijing Lin, Dan Xian, Qi Mao, Yijun Zhang, Duanzhi Duan, Ming Liu, Zhuangde Jiang. A Study on the Sub-5 nm Nano-Step Height Reference Materials Fabricated by Atomic Layer Deposition Combined with Wet Etching. Micromachines. 2022 Sep 02;13(9)

PMID: 36144077

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