Fluorocarbon assisted atomic layer etching of SiO2 and Si using cyclic Ar/C4F8 and Ar/CHF3 plasma

Metzler, Dominik; Li, Chen; Engelmann, Sebastian; Bruce, Robert L.; Joseph, Eric A.; Oehrlein, Gottlieb S.

doi:10.1116/1.4935462

Title: Fluorocarbon assisted atomic layer etching of SiO₂ and Si using cyclic Ar/C₄F₈ and Ar/CHF₃ plasma

Abstract

The need for atomic layer etching (ALE) is steadily increasing as smaller critical dimensions and pitches are required in device patterning. A flux-control based cyclic Ar/C₄F₈ ALE based on steady-state Ar plasma in conjunction with periodic, precise C₄F₈ injection and synchronized plasma-based low energy Ar⁺ ion bombardment has been established for SiO₂.¹ In this work, the cyclic process is further characterized and extended to ALE of silicon under similar process conditions. The use of CHF₃ as a precursor is examined and compared to C₄F₈. CHF₃ is shown to enable selective SiO₂/Si etching using a fluorocarbon (FC) film build up. Other critical process parameters investigated are the FC film thickness deposited per cycle, the ion energy, and the etch step length. Etching behavior and mechanisms are studied using in situ real time ellipsometry and X-ray photoelectron spectroscopy. Silicon ALE shows less self-limitation than silicon oxide due to higher physical sputtering rates for the maximum ion energies used in this work, ranged from 20 to 30 eV. The surface chemistry is found to contain fluorinated silicon oxide during the etching of silicon. As a result, plasma parameters during ALE are studied using a Langmuir probe and establish the impact of precursor additionmore » on plasma properties.« less

Authors:

Metzler, Dominik ^[1]; Li, Chen ^[1]; Engelmann, Sebastian ^[2]; Bruce, Robert L. ^[2]; Joseph, Eric A. ^[2]; Oehrlein, Gottlieb S. ^[1]

Univ. of Maryland, College Park, MD (United States)
IBM T.J. Watson Research Center, Yorktown Heights, NY (United States)

Publication Date:: Wed Nov 11 00:00:00 EST 2015

Research Org.:: Univ. of Maryland, College Park, MD (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 1225188

Grant/Contract Number:: SC0001939

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Vacuum Science and Technology A

Additional Journal Information:: Journal Volume: 34; Journal Issue: 1; Journal ID: ISSN 0734-2101

Publisher:: American Vacuum Society

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; silicon; dielectric oxides; thin films; plasma etching; ellipsometry

Citation Formats


                    Metzler, Dominik, Li, Chen, Engelmann, Sebastian, Bruce, Robert L., Joseph, Eric A., and Oehrlein, Gottlieb S. Fluorocarbon assisted atomic layer etching of SiO2 and Si using cyclic Ar/C4F8 and Ar/CHF3 plasma.  United States: N. p., 2015. 
Web.  doi:10.1116/1.4935462.

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                    Metzler, Dominik, Li, Chen, Engelmann, Sebastian, Bruce, Robert L., Joseph, Eric A., & Oehrlein, Gottlieb S. Fluorocarbon assisted atomic layer etching of SiO2 and Si using cyclic Ar/C4F8 and Ar/CHF3 plasma.  United States.  https://doi.org/10.1116/1.4935462

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                    Metzler, Dominik, Li, Chen, Engelmann, Sebastian, Bruce, Robert L., Joseph, Eric A., and Oehrlein, Gottlieb S. Wed .  
"Fluorocarbon assisted atomic layer etching of SiO2 and Si using cyclic Ar/C4F8 and Ar/CHF3 plasma".  United States.  https://doi.org/10.1116/1.4935462.  https://www.osti.gov/servlets/purl/1225188.

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@article{osti_1225188,

  title        = {Fluorocarbon assisted atomic layer etching of SiO2 and Si using cyclic Ar/C4F8 and Ar/CHF3 plasma},

  author       = {Metzler, Dominik and Li, Chen and Engelmann, Sebastian and Bruce, Robert L. and Joseph, Eric A. and Oehrlein, Gottlieb S.},

  abstractNote = {The need for atomic layer etching (ALE) is steadily increasing as smaller critical dimensions and pitches are required in device patterning. A flux-control based cyclic Ar/C4F8 ALE based on steady-state Ar plasma in conjunction with periodic, precise C4F8 injection and synchronized plasma-based low energy Ar+ ion bombardment has been established for SiO2.1 In this work, the cyclic process is further characterized and extended to ALE of silicon under similar process conditions. The use of CHF3 as a precursor is examined and compared to C4F8. CHF3 is shown to enable selective SiO2/Si etching using a fluorocarbon (FC) film build up. Other critical process parameters investigated are the FC film thickness deposited per cycle, the ion energy, and the etch step length. Etching behavior and mechanisms are studied using in situ real time ellipsometry and X-ray photoelectron spectroscopy. Silicon ALE shows less self-limitation than silicon oxide due to higher physical sputtering rates for the maximum ion energies used in this work, ranged from 20 to 30 eV. The surface chemistry is found to contain fluorinated silicon oxide during the etching of silicon. As a result, plasma parameters during ALE are studied using a Langmuir probe and establish the impact of precursor addition on plasma properties.},

  doi          = {10.1116/1.4935462},

  journal      = {Journal of Vacuum Science and Technology A},

  number       = 1,

  volume       = 34,

  place        = {United States},

  year         = {Wed Nov 11 00:00:00 EST 2015},

  month        = {Wed Nov 11 00:00:00 EST 2015}

}

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Works referencing / citing this record:

Atomic layer etching of SiO ₂ with Ar and CHF ₃ plasmas: A self‐limiting process for aspect ratio independent etching
journal, May 2019

Dallorto, Stefano; Goodyear, Andy; Cooke, Mike
Plasma Processes and Polymers, Vol. 16, Issue 9
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Interaction of long‐lived reactive species from cold atmospheric pressure plasma with polymers: Role of macromolecular structure and deep modification of aromatic polymers
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Luan, Pingshan; Oehrlein, Gottlieb S.
Plasma Processes and Polymers, Vol. 16, Issue 11
DOI: 10.1002/ppap.201900053

Anisotropic atomic layer etching of W using fluorine radicals/oxygen ion beam
journal, July 2019

Kim, Doo San; Kim, Ju Eun; Lee, Won Oh
Plasma Processes and Polymers, Vol. 16, Issue 9
DOI: 10.1002/ppap.201900081

Characterizing fluorocarbon assisted atomic layer etching of Si using cyclic Ar/C4F8 and Ar/CHF3 plasma
journal, September 2016

Metzler, Dominik; Li, Chen; Engelmann, Sebastian
The Journal of Chemical Physics, Vol. 146, Issue 5
DOI: 10.1063/1.4961458

Consequences of atomic layer etching on wafer scale uniformity in inductively coupled plasmas
journal, March 2018

Huard, Chad M.; Lanham, Steven J.; Kushner, Mark J.
Journal of Physics D: Applied Physics, Vol. 51, Issue 15
DOI: 10.1088/1361-6463/aab322

Modeling of C ₄ F ₈ inductively coupled plasmas: effects of high RF power on the plasma electrical properties
journal, August 2019

Le Dain, Guillaume; Rhallabi, Ahmed; Girard, Aurélie
Plasma Sources Science and Technology, Vol. 28, Issue 8
DOI: 10.1088/1361-6595/ab27d0

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The need for atomic layer etching (ALE) is steadily increasing as smaller critical dimensions and pitches are required in device patterning. A flux-control based cyclic Ar/C{sub 4}F{sub 8} ALE based on steady-state Ar plasma in conjunction with periodic, precise C{sub 4}F{sub 8} injection and synchronized plasma-based low energy Ar{sup +} ion bombardment has been established for SiO{sub 2} [Metzler et al., J. Vac. Sci. Technol. A 32, 020603 (2014)]. In this work, the cyclic process is further characterized and extended to ALE of silicon under similar process conditions. The use of CHF{sub 3} as a precursor is examined and comparedmore »« less
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Title: Fluorocarbon assisted atomic layer etching of SiO2 and Si using cyclic Ar/C4F8 and Ar/CHF3 plasma

Abstract

Citation Formats

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Title: Fluorocarbon assisted atomic layer etching of SiO₂ and Si using cyclic Ar/C₄F₈ and Ar/CHF₃ plasma

Atomic layer etching of SiO ₂ with Ar and CHF ₃ plasmas: A self‐limiting process for aspect ratio independent etching
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