| 研究実績の概要 |
The research to study the etching mechanism in HAR etching for 3D NAND application is divided into two parts: simulation and experiment. For the simulation, the etching of silicon based materials by fluorocarbon plasma was studied using molecular dynamics (MD). The etching yields from the simulation of SiO2 and Si3N4 etching by CF3+ ions (0.2 keV to 2 keV) were in good agreement with published ion beam experimental results. The energies in HAR etching are increasing to 10 keV, as such, the simulation was extended up to 6 keV. In line with this, ion beam experiments of SiO2 and Si3N4 etching by CF3+ ions (up to 5 keV) were done. The results showed that the experiment and simulation etching yields for SiO2 and Si3N4 were in good agreement up to 5 keV. Etching simulation of SiO2-Si3N4 bilayer, which represents a part of an oxide-nitride-oxide (ONO) multilayer used in 3D NAND, with CF3+ ions was also done to study the effect of the interface in etching. The results were summarized and presented in one domestic and one International conference both held online.
Aside from the ion beam experiments, plasma diagnostics experiments with a capacitively coupled plasma (CCP) system was also done. Langmuir probe measurement, optical emission spectroscopy (OES), impedance analysis, and current-voltage probe measurement were done on pure Ar, pure N2, and Ar-N2 plasmas. These diagnostics experiments were done to understand the factors affecting the flux during plasma etching in the HAR process.
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| 今後の研究の推進方策 |
The research implementation plan is to consolidate the results from the plasma diagnostics experiments, to continue the ion beam experiments as well as the molecular dynamics simulation for the study of the high-aspect ratio etching. The plan also include presentation of the research to domestic and international conferences. Also, all simulations and results should be finished and be summarized to at least 3 journal publications.
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