Sidewall chemistry of nano-contact patterns in C4F8 + CH2F2 + O2 + Ar inductively coupled plasmas

Nam

et al. 2020

Plasma Sci. Technol.

Self Cite

Perfluorocarbon gas is widely used in the semiconductor industry. However, perfluorocarbon has a negative effect on the global environment owing to its high global warming potential (GWP) value. An alternative solution is essential. Therefore, we evaluated the possibility of replacing conventional perfluorocarbon etching gases such as CHF 3 with C 6 F 12 O, which has a low GWP and is in a liquid state at room temperature. In this study, silicon oxynitride (SiON) films were plasma-etched using inductively coupled CF 4 +C 6 F 12 O+O 2 mixed plasmas. Subsequently, the etching characteristics of the film, such as etching rate, etching profile, selectivity over Si, and photoresist, were investigated. A double Langmuir probe was used and optical emission spectroscopy was performed for plasma diagnostics. In addition, a contact angle goniometer and x-ray photoelectron spectroscope were used to confirm the change in the surface properties of the etched SiON film surface. Consequently, the etching characteristics of the C 6 F 12 O mixed plasma exhibited a lower etching rate, higher SiON/Si selectivity, lower plasma damage, and more vertical etched profiles than the conventional CHF 3 mixed plasma. In addition, the C 6 F 12 O gas can be recovered in the liquid state, thereby decreasing global warming. These results confirmed that the C 6 F 12 O precursor can sufficiently replace the conventional etching gas.

Section: Resultsmentioning

confidence: 99%

Section: Plasma Diagnosismentioning

confidence: 94%

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Etching characteristics of thin SiON films using a liquefied perfluorocarbon precursor of C₆F₁₂O with a low global warming potential

Nam

et al. 2020

Plasma Sci. Technol.

Self Cite

“…They are a current topic for plasma simulation tools [1].The atomic layer etching to produce nanostructures in semiconductor substrates is very important for the micro-and nanoelectronics industry. CF 4 is one of the popular gases that is used in plasma etching [2][3][4][5][6]. The discharge of CF 4 is electronegative; negative ions are produced in the discharge; however, the electronegativity is weak at low pressures [7,8].…”

Section: Introductionmentioning

confidence: 99%

Fluid models calculation of Ar/CF₄ radiofrequency capacitively coupled plasmas

Elsheikh,

Abdelsalam,

Moslem

et al. 2024

Phys. Scr.

A fluid model is used to calculate plasma density in radiofrequency capacitively coupled plasmas (RF-CCPs), assuming geometrically symmetric ${\rm Ar/CF}_4$. Electrodes are powered by a 200 V sinusoidal wavefront at 13.56 MHz. The gap between the electrodes is 5 cm. The plasma species density is calculated as a function of the gas pressure, electron temperature, and gas composition. As expected from recent experiments, $\rm {CF}^+_3$ and F are dominant for all simulation parameters {\bf (Plasma Chemistry and Plasma Processing, 2022; 42: 989-1002, 2013 Pulsed Power Conference (PPC), 19th IEEE, DOI:10.1109/PPC.2013.6627595)}. The results explain the pathways to perform atomic layer etching and nanolayer deposition processes.In order to reveal the effect of electron heating on the discharge dynamics, the spatiotemporal electron energy equation is coupled with the fluid model. Tailoring the driven potential has been found to control the concentration of some plasma species. When the plasma is driven by the fundamental frequency, ohmic and stochastic heating allow electrons to be heated symmetrically. Higher harmonics give rise to an electrical asymmetry and an electron heating asymmetry between the powered and grounded sheaths. The electron temperature depends on the driven harmonics; it adjusts gain and loss rates and some plasma species densities.

ECS J. Solid State Sci. Technol.

“…However, studying the vertical sidewalls, especially when the feature size is below 100 nm, poses challenges. Previous studies have employed techniques such as wafer tilting, angle-resolved techniques, or differential charging of the trench surfaces to determine the surface composition of the sidewalls, [4][5][6][7] but do not particularly address the low-k dielectric stack at smaller trench widths.…”

mentioning

confidence: 99%

Model-Based XPS Technique for Characterization of Surface Composition on Nano-Scale SiCOH Sidewalls

Vatsal,

Rudolph,

Oehler

et al. 2023

The objective of this study is to develop an in-line metrology technique that employs X-ray photoelectron spectroscopy (XPS) to measure photoelectron intensity from patterned trench surfaces of low-k dielectric film. A mathematical model uses linear regression method to separate the intensities into individual elemental compositions of the constituent surfaces. The initial segment of the model uses measured data from CD-SEM and spectroscopic ellipsometry to determine the respective surface areas visible to the XPS electron analyzer. The second segment derives the surface composition of the line top, trench bottom, and vertical sidewalls based on a linear relationship between photoelectron intensity, emitting area, and characteristic elemental composition of each surface. The study has verified the predicted compositions from the model through physical measurements, demonstrating excellent agreement and concurrence with the physical mechanisms expected from the applied etch and ash chemistry in a commercial CCP RIE etch chamber.