On the LPCVD-Formed SiO2 Etching Mechanism in CF4/Ar/O2 Inductively Coupled Plasmas: Effects of Gas Mixing Ratios and Gas Pressure

Son, Jin-Young; Efremov, Alexander; Chun, Inwoo; Yeom, Geun Young; Kwon, Kwang‐Ho

doi:10.1007/s11090-013-9513-1

Cited by 21 publications

(21 citation statements)

References 30 publications

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“…The effective ion mass was evaluated according to Blank’s law as

, where

and

are partial ion fractions and masses, respectively. For each type of positive ion, it was suggested that

[ 40 ], where

is the fraction of corresponding neutral particles with the ionization rate coefficient of

[ 55 , 58 ].…”

Section: Methodsmentioning

confidence: 99%

“…Accordingly, the polymer deposition rate may be traced by the

ratio [ 35 , 36 , 37 ], where

is the total flux of polymerizing radicals (

in CF 4 - and C 4 F 8 - based plasmas while

in CHF 3 - based plasmas). Accordingly, parameters

and

characterize the change in the polymer film thickness due to physical (destruction by ion bombardment) and chemical (etching by O atoms) destruction pathways, respectively [ 35 , 36 , 40 , 48 ].…”

Section: Methodsmentioning

confidence: 99%

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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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“…The effective ion mass was evaluated according to Blank’s law as

, where

and

are partial ion fractions and masses, respectively. For each type of positive ion, it was suggested that

[ 40 ], where

is the fraction of corresponding neutral particles with the ionization rate coefficient of

[ 55 , 58 ].…”

Section: Methodsmentioning

confidence: 99%

“…Accordingly, the polymer deposition rate may be traced by the

ratio [ 35 , 36 , 37 ], where

is the total flux of polymerizing radicals (

in CF 4 - and C 4 F 8 - based plasmas while

in CHF 3 - based plasmas). Accordingly, parameters

and

Section: Methodsmentioning

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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“…Dry-etching processes as a micro-patterning technology are very important in integrating the BZN thin films into a Si-based circuitry. Many studies on dry-etching processes for various kinds of specimens have been reported [9][10][11][12][13][14][15][16], where various of etching parameters having effects on the surface and structure of films were involved. However, only a few studies on BZN thin films have been published [17,18].…”

Section: Introductionmentioning

confidence: 99%

Pressure-Dependent Etching Mechanism and Induced Dielectric Properties Variation of BZN Thin Films in SF6/Ar Plasma

Dai

Song

Wang

et al. 2015

Plasma Chem Plasma Process

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Reactive ion etching was used to study bismuth zinc niobate (BZN) thin films etching in SF 6 /Ar plasma as a function of pressure. The etch rate increases as the pressure increases from 1 to 20 mTorr and decreases when the pressure exceeds 20 mTorr. The film surfaces were analyzed to determine the etching mechanism using X-ray photoelectron spectroscopy. Pressure is found to have an effect on etch reaction and non-volatile etch byproducts removal through different ion density and energy, thus resulting in varying compositions, element chemical binding states on the film surface. Dielectric properties of the film, modified by SF 6 /Ar plasma, show an obvious variation with pressure. The permittivity shows a slight decrease in the range of 1-20 mTorr but a sharp decrease at 30 mTorr. Instead, the dielectric loss variation exhibits an opposite trend.

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“…Until now, there were enough works reported on etching characteristics and mechanisms for SiO 2 in fluorocarbon gas plasmas [3][4][5][6][7][8][9][10][11][12][13]. Results of these works allow one to conclude that: 1) In all fluorocarbon-based gas chemistries, the dominant contribution to the chemical etching of SiO 2 is provided by F atoms [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…From the others side, results of Refs. [10,15,16] clearly indicated that Ar/O 2 mixing ratio at constant fraction of fluorocarbon component is a powerful tool to adjust densities of F atoms and polymerizing radicals. Accordingly, the idea of current work was to perform the comparative study of SiO 2 etching kinetics in CF 4 + Ar + O 2 and C 4 F 8 + Ar + O 2 plasmas with various Ar/O 2 mixing ratios as well as to analyze the relationships between gas-phase plasma parameters and heterogeneous reaction pathways determining the features of SiO 2 etching mechanisms.…”

Section: Introductionmentioning

confidence: 99%

FEATURES OF SiO2 REACTIVE-ION ETCHING KINETICS IN CF4 + Ar + O2 AND C4F8 + Ar + O2 GAS MIXTURES

Efremov

Sobolev

2020

IVKKT

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The effect of Ar/O2 mixing ratio on gas-phase characteristics and SiO2 etching kinetics in CF4 + Ar + O2 and C4F8 + Ar + O2 plasmas was studied under conditions of 13.56 MHz inductive RF discharge. The constant processing parameters were fraction of fluorocarbon component in a feed gas (50%) total gas pressure (6 mTorr), input power (700 W) and bias power (200 W). It was found that the full substitution of Ar for O2 in both gas systems results in non-monotonic (with a maximum at ~ 25% Ar + 25% O2) SiO2 etching rates as well as in monotonically increasing photoresist etching rate with higher absolute values for CF4-containing mixture. The steady-state densities of active species were determined using a combination of plasma diagnostics by Langmuir probes and 0-dimensional (global) plasma modeling. Corresponding results indicated that both gas systems are characterized by quite close parameters of electron and ion components while exhibit sufficient differences in the kinetics of neutral species, especially in the presence of O2. The latter produces opposite changes in F atom density as well as in effective probability of ion-assisted chemical reaction vs. Ar/O2 mixing ratio. Relationships between type of fluorocarbon component and heterogeneous process kinetics were analyzed through the set of gas-phase-related parameters (fluxes, flux-to-flux ratios) characterizing chemical etching pathways for SiO2 and formation/destruction balance for the fluorocarbon polymer film. It was suggested that the transition toward O2-rich plasma in the low-polymerizing CF4 + Ar + O2 plasma suppresses the effective probability for SiO2 + F reaction through decreasing efficiency for oxide bond breaking and desorption of etching products due to decreasing ion energy flux. Oppositely, an increase in O2 content in the high-polymerizing C4F8 + Ar + O2 mixture lifts up the effective reaction probability by decreasing fluorocarbon film thickness and providing better access of F atoms to the etched surface.

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On the LPCVD-Formed SiO2 Etching Mechanism in CF4/Ar/O2 Inductively Coupled Plasmas: Effects of Gas Mixing Ratios and Gas Pressure

Cited by 21 publications

References 30 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

Pressure-Dependent Etching Mechanism and Induced Dielectric Properties Variation of BZN Thin Films in SF6/Ar Plasma

FEATURES OF SiO2 REACTIVE-ION ETCHING KINETICS IN CF4 + Ar + O2 AND C4F8 + Ar + O2 GAS MIXTURES

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