A Comparative Study of HBr-Ar and HBr-Cl2 Plasma Chemistries for Dry Etch Applications

Efremov, Alexander; Kim, Youngkeun; Lee, Hyun-Woo; Kwon, Kwang‐Ho

doi:10.1007/s11090-010-9279-7

Cited by 33 publications

(24 citation statements)

References 38 publications

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“…-Silicon etching rates in HBr plasma are lower than those in Cl2 plasma under one and the same processing conditions [5]. Such difference is in agreement with differences in volume densities and fluxes of halogen atoms in corresponding gas systems [9,11,12]. Also, the addition of O2 to HBr or Cl2 slows Si etching rate, but allows one to obtain the more anisotropic etching [13,14].…”

Section: Introductionsupporting

confidence: 54%

“…In order to analyze the influence of HBr/O2 and Cl2/O2 mixing ratios on kinetics and densities of plasma active species, we developed a simplified 0-dimensional (global) kinetic model operated with volume-averaged plasma parameters. Similar to our previous works [11,12], the model was based on the simultaneous solution of steady-state kinetic equations with using the experimental data on Te and J+ as the input parameters. The set of chemical reactions was taken from Refs.…”

Section: Experimental and Modeling Detailsmentioning

confidence: 99%

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ON MECHANISMS OF OXYGEN INFLUENCE ON GAS-PHASE PARAMETERS AND SILICON REACTIVE-ION ETCHING KINETICS IN HBr + Cl2 + O2 PLASMA

Efremov

Рыбкин

Бетелин

et al. 2019

IVKKT

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The effects of both HBr/O2 and Cl2/O2 mixing ratios in HBr+Cl2+O2 gas mixture on plasma parameters, steady-state densities of active species and Si etching kinetics were studied under the typical conditions of reactive ion etching process: total gas pressure (p = 10 mTorr), input power (W = 500 W), bias power (Wdc = 200 W). The data on internal plasma parameters and plasma chemistry were obtained using a combination of Langmuir probe diagnostics and 0-dimensional (global) plasma modeling. It was found that the variation in HBr/O2 mixing ratio at constant Cl2 fraction in a feed gas is characterized by the stronger impact on the steady-state plasma composition through both electron-impact and atom-molecular reaction kinetics as well as allows one to obtain the wider change in the total halogen atom density. It was shown that changes in both HBr/O2 and Cl2/O2 mixing ratios toward O2-rich plasmas lowers the Si etching rate that exhibits no evident correlations with total halogen atom flux and ion energy flux. The model-based analysis of Si etching kinetics allowed one to conclude that the effective reaction probability for Si + Cl/Br heterogeneous reaction depends on the flux of oxidative species – oxygen atoms and OH radicals. The reasons may be 1) the oxidation of silicon resulting in higher reaction threshold energy; and 2) the decreasing fraction of free adsorption sites for Cl/Br atoms due to the oxidation of reaction products into the lower volatile SiBrxOy and SiClxOy compounds.

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Section: Introductionsupporting

confidence: 54%

Section: Experimental and Modeling Detailsmentioning

confidence: 99%

ON MECHANISMS OF OXYGEN INFLUENCE ON GAS-PHASE PARAMETERS AND SILICON REACTIVE-ION ETCHING KINETICS IN HBr + Cl2 + O2 PLASMA

Efremov

Рыбкин

Бетелин

et al. 2019

IVKKT

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“…In particular, H recombine to H 2 with a probability of 0.7, [18] Cl recombine to Cl 2 with a probability of 0.1. [20] Likewise, the probability for recombination of Br, and O has been reported as 0.1 [8] and 0.1, [21,22] respectively. The overall flux of neutral specie i is…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…[5][6][7] In particular, plasma of hydrogen bromide (HBr) integrated with noble gases (e.g., Argon: Ar or Helium: He) has demonstrated higher anisotropy and selectivity for etching of Si-wafer; however, a lower etching rate was reported. [8][9][10][11][12][13] Nevertheless, the etching rate of HBr plasmas can be significantly improved by introducing molecular gases such as chlorine (Cl 2 ) in the plasma, most likely because of the chemically reactive nature of Cl. Alternatively, providing noble gas (e.g., Ar) environment has been postulated to trigger the plasma discharge at considerably low pressures.…”

Section: Introductionmentioning

confidence: 99%

Computational characterization of capacitive coupled HBr/Cl₂/O₂ plasma

Gul

Iqbal

Khan

et al. 2022

Contributions to Plasma Physics

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A self‐consistent two‐dimensional fluid model was used to study HBr/Cl2/O2 plasma discharge. A comprehensive set of 150 reactions comprising different processes (i.e., dissociation, ionization, and excitation) in tandem with 32 plasma species were considered in the computational model. The results revealed that the plasma reactions were dominated by 11 species (i.e., Cl, Cl+, Cl2+, H, H2, HCl, HCl+, Br, Br+, Br2, and HBr+), where the neutral species outnumbered the charged species. The density of charged species in the plasma reactor followed a bell shaped while the neutral species followed a double humped shaped distribution. The increase in plasma O2 concentration resulted in an initial decrease, followed by a gradual increase in the generation of Cl, Br, H, Cl+, and Br+ in the plasma discharge. A lower/higher concentration of oxygen in the plasma stimulated the densities of neutral/charged species, which facilitated the chemical/physical etching pathway. These findings provide new insights into the type of etching species and their optimization in the HBr/Cl2/O2 plasma discharge, with potential applications in the semiconductor industry.

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“…The most popular mixtures to etch Si are Cl 2 /O 2 /Ar, CF 4 /O 2 , SF 6 /O 2 and (He/)H 2 /HBr, or a combination. [14][15][16][17][18][19][20][21] . Indeed, the shift towards more complex gas mixtures for smaller device etching is clearly visible.…”

Section: Introductionmentioning

confidence: 99%

Computational study of the CF₄ /CHF₃ / H₂ /Cl₂ /O₂ /HBr gas phase plasma chemistry

Tinck¹,

Bogaerts²

2016

J. Phys. D: Appl. Phys.

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A modelling study is performed of high-density low-pressure inductively coupled CF 4 /CHF 3 /H 2 /Cl 2 /O 2 /HBr plasmas under different gas mixing ratios. A reaction set describing the complete plasma chemistry is presented and discussed. The gas fraction of each component in this mixture is varied to investigate the sensitivity of the plasma properties, like electron density, plasma potential and species densities, towards the gas mixing ratios. This research is of great interest for microelectronics applications because these gases are often combined in 2-(or more-)component mixtures, and mixing gases or changing the fraction of a gas can sometimes yield unwanted reaction products or unexpected changes in the overall plasma properties due to the increased chemical complexity of the system. Increasing the CF 4 fraction produces more F atoms for chemical etching as expected, but also more prominently lowers the density of Cl atoms, resulting in an actual drop in the etch rate under certain conditions. Furthermore, CF 4 decreases the free electron density when mixed with Cl 2 . However, depending on the other gas components, CF 4 gas can also sometimes enhance free electron density. This is the case when HBr is added to the mixture. The addition of H 2 to the gas mixture will lower the sputtering process, not only due to the lower overall positive ion density at higher H 2 fractions, but also because more H + , H 2 + and H 3 + are present and they have very low sputter yields. In contrast, a larger Cl 2 fraction results in more chemical etching but also in less physical sputtering due to a smaller abundance of positive ions.Increasing the O 2 fraction in the plasma will always lower the etch rate due to more oxidation of the wafer surface and due to a lower plasma density. However, it is also observed that the density of F atoms can actually increase with rising O 2 gas fraction. This is relevant to note because the exact balance between fluorination and oxidation is important for fine-tuning the overall etch rate and for control of the sidewall profile.Finally, HBr is often used as a chemical etcher, but when mixed with F-or Cl-containing gases, HBr creates the same diluting effects as Ar or He, because a higher fraction results in less chemical etching but more (physical) sputtering.

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A Comparative Study of HBr-Ar and HBr-Cl2 Plasma Chemistries for Dry Etch Applications

Cited by 33 publications

References 38 publications

ON MECHANISMS OF OXYGEN INFLUENCE ON GAS-PHASE PARAMETERS AND SILICON REACTIVE-ION ETCHING KINETICS IN HBr + Cl2 + O2 PLASMA

ON MECHANISMS OF OXYGEN INFLUENCE ON GAS-PHASE PARAMETERS AND SILICON REACTIVE-ION ETCHING KINETICS IN HBr + Cl2 + O2 PLASMA

Computational characterization of capacitive coupled HBr/Cl₂/O₂ plasma

Computational study of the CF₄ /CHF₃ / H₂ /Cl₂ /O₂ /HBr gas phase plasma chemistry

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A Comparative Study of HBr-Ar and HBr-Cl2 Plasma Chemistries for Dry Etch Applications

Cited by 33 publications

References 38 publications

ON MECHANISMS OF OXYGEN INFLUENCE ON GAS-PHASE PARAMETERS AND SILICON REACTIVE-ION ETCHING KINETICS IN HBr + Cl2 + O2 PLASMA

ON MECHANISMS OF OXYGEN INFLUENCE ON GAS-PHASE PARAMETERS AND SILICON REACTIVE-ION ETCHING KINETICS IN HBr + Cl2 + O2 PLASMA

Computational characterization of capacitive coupled HBr/Cl2/O2 plasma

Computational study of the CF4 /CHF3 / H2 /Cl2 /O2 /HBr gas phase plasma chemistry

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Computational characterization of capacitive coupled HBr/Cl₂/O₂ plasma

Computational study of the CF₄ /CHF₃ / H₂ /Cl₂ /O₂ /HBr gas phase plasma chemistry