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 »
- Authors:
-
- Univ. of Maryland, College Park, MD (United States)
- IBM T.J. Watson Research Center, Yorktown Heights, NY (United States)
- Publication Date:
- 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.
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
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.
@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}
}
Web of Science
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
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Characterizing fluorocarbon assisted atomic layer etching of Si using cyclic Ar/C4F8 and Ar/CHF3 plasma
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