Model and probe measurements of inductively coupled CF4 discharges

Kimura, Takashi; Ohe, K.

doi:10.1063/1.1491023

Cited by 51 publications

(27 citation statements)

References 33 publications

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“…The model used following assumptions: 1) The electron energy distribution function (EEDF) is close to Maxwellian one. The applicability of Maxwellian EEDFs for the description of the electron-impact kinetics for CF4-based low-pressure ( < 50 mTorr) ICPs has been confirmed by the reasonable agreement between the diagnostic results and modeling [11,12]; 2) Under the given set of process conditions, the electronegativity of CF4+C4F8+Ar plasma with more than 30% fraction of electropositive components is low enough to assume << ≈ . The reasonability of such approach for the CF4-and C4F8-based ICPs was confirmed in several works by both modeling and experiment [6,12,13];…”

Section: Experimental and Modeling Detailsmentioning

confidence: 77%

“…That is why, one cannot expect an increase in the effective ionization frequency toward increasing C4F8 content in a feed gas. And secondly, under one and the same operating conditions the electronegativity of the C4F8 plasma is lower than that for CF4 one [12,14]. Therefore, the substitution of CF4 for C4F8 in the CF4+C4F8+Ar gas mixture leads to increasing electron diffusion coefficient and thus, to increasing electron decay rate on the reactor walls.…”

Section: Resultsmentioning

confidence: 96%

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PLASMA PARAMETERS AND ACTIVE SPECIES KINETICS IN CF4+C4F8+Ar GAS MIXTURE

Efremov

Murin

Kwon³

2018

IVUZKKT

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This work discusses the relationships between the initial composition of the CF4 + C4F8 + Ar gas mixture, gas-phase characteristics and heterogeneous process kinetics under the condition of low-pressure inductively coupled plasma. The goals were to investigate how the CF4/C4F8 mixing ratio influences internal plasma parameters (electron temperature, electron density and ion bombardment energy) and kinetics of plasma active species as well as to analyze how the changes in above parameters may influence the dry etching characteristics, such as etching rates and selectivities. The investigation was carried out using the combination of plasma diagnostics by double Langmuir probes and 0-dimensional plasma modeling. Both experiments and calculations were carried out at constant gas pressure (10 mTorr), input power (800 W) and bias power (150 W) while the CF4/C4F8 mixing ratio was varied through the partial flow rates for corresponding gases. It was shown that the substitution of CF4 for C4F8 in the CF4+C4F8+Ar feed gas lowers F atom formation rates and causes the decreasing F atom flux to the treated surface due to decreasing their volume density. It was proposed that an increase in the densities and fluxes of unsaturated CFx (x=1,2) radicals toward C4F8-rich plasmas at the nearly constant ion energy flux (i.e. at the nearly constant efficiency of ion bombardment) causes a decrease in the effective reaction probability for F atoms through the increasing thickness of the fluorocarbon polymer film on the treated surface.Forcitation:Efremov A.M., Murin D.B., Kwon K.H. Plasma parameters and active species kinetics CF4+C4F8+Ar gas mixture. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N4-5. P. 31-36

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Section: Experimental and Modeling Detailsmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 96%

PLASMA PARAMETERS AND ACTIVE SPECIES KINETICS IN CF4+C4F8+Ar GAS MIXTURE

Efremov

Murin

Kwon³

2018

IVUZKKT

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“…25 From Refs. [26][27][28], one can propose that the greater polymerizing effect of C 4 F 8 is connected with the higher CF and CF 2 radical densities. It was also found that the dilution of C 4 F 8 by approximately 40-50% Ar shifts the dominant surface process pathway from polymerization to etching.…”

Section: Introductionmentioning

confidence: 99%

Application of Si and SiO₂ Etching Mechanisms in CF₄/C₄F₈/Ar Inductively Coupled Plasmas for Nanoscale Patterns

Lee¹,

Efremov²,

Yeom³

et al. 2015

j nanosci nanotechnol

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An investigation of the etching characteristics and mechanism for both Si and SiO2 in CF4/C4F8/Ar inductively coupled plasmas under a constant gas pressure (4 mTorr), total gas flow rate (40 sccm), input power (800 W), and bias power (150 W) was performed. It was found that the variations in the CF4/C4F8 mixing ratio in the range of 0-50% at a constant Ar fraction of 50% resulted in slightly non-monotonic Si and SiO2 etching rates in CF4-rich plasmas and greatly decreasing etching rates in C4F8-rich plasmas. The zero-dimensional plasma model, Langmuir probe diagnostics, and optical emission spectroscopy provided information regarding the formation-decay kinetics for the plasma active species, along with their densities and fluxes. The model-based analysis of the etching kinetics indicated that the non-monotonic etching rates were caused not by the similar behavior of the fluorine atom density but rather by the opposite changes of the fluorine atom flux and ion energy flux. It was also determined that the great decrease in both the Si and SiO2 etching rates during the transition from the CF4/Ar to C4F8/Ar gas system was due to the deposition of the fluorocarbon polymer film.

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“…[11][12][13] The models for studying tetrafluoromethane (CF 4 ) plasma in either capacitive coupled plasma or inductively coupled plasma used for etching purpose have been reported. These include the global models with complex gas-phase reactions [14][15][16][17] and the fluid models considering feeding gas-phase reactions and highly simplified surface reactions using the concept of stick coefficients without taking any etching products into account. [18][19][20][21] However, the consideration of etching products from the substrate is critical in faithfully modeling of these discharges since they can significantly influence the composition of the gas phase species in CF 4 discharge for the etching of SiO 2 and Si.…”

Section: Introductionmentioning

confidence: 99%

Parallel 2D Axisymmetric Fluid Modeling of CF₄ Discharge in an Inductively Coupled Plasma Source During SiO₂ Etching

Chiu¹,

Chiang

Hung³

et al. 2014

Plasma Processes & Polymers

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A parallel 2D axisymmetric plasma fluid modeling for an inductively coupled plasma source with tetrafluoromethane precursor is reported. In total, 32 species with 96 gas-phase and 27 surface reactions with site-balance equations are considered. The predicted results of major species densities are in reasonable agreement with reported experiments. The etching products, e.g. SiF x and O 2 , are found to be appreciable ($10%) compared to the precursor near the substrate. The predicted density trends, such as CF x þ and CF x (x ¼ 1-3), are also consistent with reported experiments. Finally, the predicted etching rate on the SiO 2 substrate is presented and discussed in detail.

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Model and probe measurements of inductively coupled CF4 discharges

Cited by 51 publications

References 33 publications

PLASMA PARAMETERS AND ACTIVE SPECIES KINETICS IN CF4+C4F8+Ar GAS MIXTURE

PLASMA PARAMETERS AND ACTIVE SPECIES KINETICS IN CF4+C4F8+Ar GAS MIXTURE

Application of Si and SiO₂ Etching Mechanisms in CF₄/C₄F₈/Ar Inductively Coupled Plasmas for Nanoscale Patterns

Parallel 2D Axisymmetric Fluid Modeling of CF₄ Discharge in an Inductively Coupled Plasma Source During SiO₂ Etching

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Model and probe measurements of inductively coupled CF4 discharges

Cited by 51 publications

References 33 publications

PLASMA PARAMETERS AND ACTIVE SPECIES KINETICS IN CF4+C4F8+Ar GAS MIXTURE

PLASMA PARAMETERS AND ACTIVE SPECIES KINETICS IN CF4+C4F8+Ar GAS MIXTURE

Application of Si and SiO2 Etching Mechanisms in CF4/C4F8/Ar Inductively Coupled Plasmas for Nanoscale Patterns

Parallel 2D Axisymmetric Fluid Modeling of CF4 Discharge in an Inductively Coupled Plasma Source During SiO2 Etching

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Application of Si and SiO₂ Etching Mechanisms in CF₄/C₄F₈/Ar Inductively Coupled Plasmas for Nanoscale Patterns

Parallel 2D Axisymmetric Fluid Modeling of CF₄ Discharge in an Inductively Coupled Plasma Source During SiO₂ Etching