Evaluation of absolute charge density at the bottom of high aspect capillary holes exposed to a pulsed very high frequency plasma

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The time-varying mechanism of the positive-ion composition in a pulse-modulated Ar/C4F8/O2 dual-frequency capacitively coupled plasma was investigated in detail using a quadrupole mass spectrometer equipped with an electrostatic energy analyzer. Time-resolved measurements of the ion composition with respect to the pulse-off period ( T off ) revealed that the electron temperature ( T e ) just after turning on the pulse is an important factor in determining the ratio of the ionization rates of the Ar+ and C x F y + ions. The time-varying phenomenon of the ion composition was also investigated through a numerical analysis based on the particle balance model, considering the production and loss rates of ions, ion–ion recombination processes, and ion–molecule reactions. When the VHF power ( P VHF ) was increased, a decrease in the ambipolar diffusion loss time constants of the ions ( τ loss i ) was observed, and the change in electronegativity was pointed out as the cause of this phenomenon.

Section: Influence Of T Off and P Vhf On The Ion Compositionmentioning

confidence: 99%

Time-varying mechanism of ion composition in a pulse-modulated Ar/C₄F₈/O₂ dual-frequency capacitively coupled plasma

Kuboi,

Kato,

Akatsuka

et al. 2023

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“…142) The charge density at the bottom was monitored using the capillary-hole method. 143,144) The angular distributions of energetic neutrals and ions were analyzed. 145) 2.8.…”

Section: 5mentioning

confidence: 99%

Science-based, data-driven developments in plasma processing for material synthesis and device-integration technologies

Kambara

Kawaguchi

Lee

et al. 2022

Low-temperature plasma processing technologies is essential for material synthesis, device fabrication, and surface treatment. The development of plasma-related products and services requires an understanding of the multiscale complex behaviors of plasma and the hierarchical integration of plasma generation, energy and mass transports through sheath region, surface reactions, and other processes. The importance of science-based and data-driven approaches to controlling systems is argued. The state-of-the-art of deep learning, machine learning, and artificial intelligence in low-temperature plasma science and technology is reviewed. In this review, the requirements and challenges for plasma parameter prediction and processing recipe discovery are asserted by researchers in the fields of material science and plasma processing. It also outlined a science-based, data-driven approach for development of virtual metrology in plasma processes.

“…24,26) On the contrary, pulsed plasma with pulsing source power has also been studied extensively. [27][28][29][30][31][32][33] Pulsed plasma provides variable electron temperature and plasma density by pulsing. It controls dissociation and supplies highly selective etch.…”

Section: Introductionmentioning

confidence: 99%

Highly selective Si₃N₄ etching on Si using pulsed-microwave CH₃F/O₂/Ar plasma

Morimoto

Matsui

Ikeda

et al. 2023

Highly selective Si3N4 etching on Si was achieved in a CH3F/O2/Ar plasma using pulsed-microwave plasma and time-modulation (TM) bias. The Si3N4/Si selectivity reached infinity at a peak-to-peak voltage (Vpp) of 240 V. The effect of pulsed-microwave on CH3F gas dissociation for highly selective Si3N4 etching was investigated by deposited film analysis, optical emission spectroscopy (OES), and ion current flux measurements. As the duty cycle of the pulsed-microwave was decreased, the plasma density during the pulse on period decreased and the CH/H ratio increased. The pulsed-microwave plasma produced low-dissociation radicals by providing a low plasma density. The low-dissociation radicals in the CH3F plasma formed a fluorine (F)-rich hydrofluorocarbon (HFC) layer on the Si3N4 wafer surface. The F-rich HFC layer promotes Si3N4 etching even at low ion energy, where Si etching does not proceed, and enables highly selective Si3N4 etching on Si.