Concerning the Effect of Type of Fluorocarbon Gas on the Output Characteristics of the Reactive-Ion Etching Process

Efremov, Alexander; Murin, D. B.; Kwon, Kwang‐Ho

doi:10.1134/s1063739720020031

Cited by 25 publications

(34 citation statements)

References 23 publications

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“…In order to obtain information on the kinetics and densities of plasma active species, we applied a simplified 0-dimensional (global) kinetic model [47,48]. A set of chemical reactions with corresponding rate coefficients was taken from our previous works that dealt with the modeling of CF 4 + Ar/O 2 [40,[47][48][49][50], CHF 3 + Ar/O 2 [50][51][52][53] and C 4 F 8 + Ar/O 2 [36,39,43,48,54] plasmas. The basic model approaches were as follows:…”

Section: Approaches For Analysis Of Gas-phase Chemistrymentioning

confidence: 99%

On Relationships between Gas-Phase Chemistry and Reactive Ion Etching Kinetics for Silicon-Based Thin Films (SiC, SiO2 and SixNy) in Multi-Component Fluorocarbon Gas Mixtures

2021

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This work summarizes the results of our previous studies related to investigations of reactive ion etching kinetics and mechanisms for widely used silicon-based materials (SiC, SiO2, and SixNy) as well as for the silicon itself in multi-component fluorocarbon gas mixtures. The main subjects were the three-component systems composed either by one fluorocarbon component (СF4, C4F8, CHF3) with Ar and O2 or by two fluorocarbon components with one additive gas. The investigation scheme included plasma diagnostics by Langmuir probes and model-based analysis of plasma chemistry and heterogeneous reaction kinetics. The combination of these methods allowed one (a) to figure out key processes which determine the steady-state plasma parameters and densities of active species; (b) to understand relationships between processing conditions and basic heterogeneous process kinetics; (c) to analyze etching mechanisms in terms of process-condition-dependent effective reaction probability and etching yield; and (d) to suggest the set gas-phase-related parameters (fluxes and flux-to-flux ratios) to control the thickness of the fluorocarbon polymer film and the change in the etching/polymerization balance. It was shown that non-monotonic etching rates as functions of gas mixing ratios may result from monotonic but opposite changes in F atoms flux and effective reaction probability. The latter depends either on the fluorocarbon film thickness (in high-polymerizing and oxygen-less gas systems) or on heterogeneous processes with a participation of O atoms (in oxygen-containing plasmas). It was suggested that an increase in O2 fraction in a feed gas may suppress the effective reaction probability through decreasing amounts of free adsorption sites and oxidation of surface atoms.

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Section: Approaches For Analysis Of Gas-phase Chemistrymentioning

confidence: 99%

On Relationships between Gas-Phase Chemistry and Reactive Ion Etching Kinetics for Silicon-Based Thin Films (SiC, SiO2 and SixNy) in Multi-Component Fluorocarbon Gas Mixtures

2021

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“…1 represents effects of CF4/C4F8 mixing ratio and bias power on electrons-and ions-related gas-phase characteristics. The analysis of these data with accounting for the previous research experience of CF4 + Ar [9,13], C4F8 + Ar [9][10][11]13] and CF4 + + C4F8 + Ar [10][11][12] plasmas allows one to formulate several important features which may be useful for the optimization of corresponding RIE process. These are as follows:…”

Section: Methodsmentioning

confidence: 99%

“…1(d)), where i = e(-Udc-Uf) is the ion bombardment energy, and Uf = f(Te) [4] is the floating potential. As the sputtering yield is generally proportional to the momentum transferred from the incident ion to the surface atom [4], the multiplication of i 1/2 + traces the ion bombardment intensity [9,10]. Therefore, the somewhat activation of ion-driven heterogeneous processes also takes place.…”

Section: Methodsmentioning

confidence: 99%

“…In our previous works [9][10][11][12][13], we carried out detailed investigations of gas mixing effects in binary and ternary gas systems composed by CF4, C4F8 and Ar under conventional RIE conditions (gas pressures below 50 mtorr, input power densities of 0.5-0.1 W/cm 3 that correspond to the plasma density of  10 10 -10 11 cm -3 , and ion bombardment energies above 1) An increase in Ar fraction in both CF4 +Ar and C4F8 + Ar plasmas changes electrons-and ionsrelated plasma parameters and thus, influences both gas-phase and heterogeneous reaction kinetics. Most principal effect here are a) the elevation of electron temperature and plasma density; b) the increasing efficiency of electron-impact processes that results in slower decrease of F atoms density [9,10]; and c) the growth of ion bombardment intensity that accelerates ion-driven heterogeneous processes, such as surface bond breaking, the desorption of low volatile reaction products and the destruction of fluorocarbon polymer film. As such, the change in the effective probability of ion-assisted chemical reaction represents the superposition of all above effects [11,12].…”

Section: Introductionmentioning

confidence: 97%

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PLASMA COMPOSITION AND SiO2 ETCHING KINETICS IN CF4/C4F8/Ar/He MIXTURE: EFFECTS OF CF4/C4F8 MIXING RATIO AND BIAS POWER

2022

Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.

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Gas-phase characteristics as well as reactive-ion etching kinetics of silicon dioxide in CF4/C4F8/Ar/He plasma with variable CF4/C4F8 mixing ratio and bias potential were investigated under conditions of low (~ 0.05 W/cm3) input power regime. The interest to such regime is due to the possibility to obtain higher etching anisotropy with lower surface damages. The research scheme included plasma diagnostics by Langmuir probes and optical emission spectroscopy in the internal (with no use of standard additives) actinometry approach. It was shown that the substitution of C4F8 for CF4 does not produce sufficient changes in both electrons- and ions-related plasma parameters, but causes a weak increase in fluorine atom density. On the contrary, an increase in the bias power (and thus, in the bias potential) does not disturb plasma composition, but is characterized by proportional changes in the ion bombardment energy. As such, selected variable parameters represent somewhat classical “chemical” and “physical” factors influencing heterogeneous stages of the etching process. It was found that the dominant contribution to the SiO2 etching process belongs to its chemical component while bias powers above 400 W provide no dependence of Si(s.) + xF → SiFx (where index (s.) points out the particle situated on the surface) reaction probability on the efficiency of ion-induced production of adsorption sites for fluorine atoms, as SiOx(s.) → Si(s.) + xO. At lower bias powers, the presence of such dependence is confirmed by similar changes of effective reaction probability and ion bombardment intensity, traced by the multiplication of ion flux on square root of ion energy. Some suggestions concerning peculiarities of both gas-phase and heterogeneous process kinetics at low plasma densities were made.

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“…This form of etching is carried out at little pressure using inert or reactive gases. The most commonly used dry etchants are hydrogen fluoride [ 168 ], fluorocarbons [ 169 ], xenon difluoride [ 170 ], oxygen [ 171 ] and boron trichloride [ 172 ]. Dry etching is considered a huge scale integration (VLSI) process as it could be more exactly controlled by regulating parameters like gas pressure, temperature and electric field distribution.…”

Section: Techniques Of Preparation Of Mns (Mns)mentioning

confidence: 99%

Recent Advancements in Microneedle Technology for Multifaceted Biomedical Applications

Kulkarni¹,

Damiri

Rojekar

et al. 2022

Pharmaceutics

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Microneedle (MNs) technology is a recent advancement in biomedical science across the globe. The current limitations of drug delivery, like poor absorption, low bioavailability, inadequate skin permeation, and poor biodistribution, can be overcome by MN-based drug delivery. Nanotechnology made significant changes in fabrication techniques for microneedles (MNs) and design shifted from conventional to novel, using various types of natural and synthetic materials and their combinations. Nowadays, MNs technology has gained popularity worldwide in biomedical research and drug delivery technology due to its multifaceted and broad-spectrum applications. This review broadly discusses MN’s types, fabrication methods, composition, characterization, applications, recent advancements, and global intellectual scenarios.

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Concerning the Effect of Type of Fluorocarbon Gas on the Output Characteristics of the Reactive-Ion Etching Process

Cited by 25 publications

References 23 publications

On Relationships between Gas-Phase Chemistry and Reactive Ion Etching Kinetics for Silicon-Based Thin Films (SiC, SiO2 and SixNy) in Multi-Component Fluorocarbon Gas Mixtures

On Relationships between Gas-Phase Chemistry and Reactive Ion Etching Kinetics for Silicon-Based Thin Films (SiC, SiO2 and SixNy) in Multi-Component Fluorocarbon Gas Mixtures

PLASMA COMPOSITION AND SiO2 ETCHING KINETICS IN CF4/C4F8/Ar/He MIXTURE: EFFECTS OF CF4/C4F8 MIXING RATIO AND BIAS POWER

Recent Advancements in Microneedle Technology for Multifaceted Biomedical Applications

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