Atomic layer etching of SiO2 by alternating an O2 plasma with fluorocarbon film deposition

Tsutsumi, Takayoshi; Kondo, Hiroki; Hori, Masaru; Zaitsu, Masaru; Kobayashi, Akiko; Nozawa, Toshihisa; Kobayashi, Nozomu

doi:10.1116/1.4971171

Cited by 46 publications

(26 citation statements)

References 25 publications

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“…During Ar + bombardment, the FC layer is transformed from a layer rich in CF 2 and CF 3 into one with a majority of F-deficient CF and C-(CF x )F y . This is in good agreement with previously published ALE SiO 2 studies [4,23,24,35]. In addition, some residual F bound mostly to Si is present in the near surface region, as seen in the F(1s) spectra in figure 10(b).…”

Section: Ar + Ion Bombardment Of Fluorocarbon-dosed Surfacessupporting

confidence: 92%

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Atomic layer etching of silicon dioxide using alternating C₄F₈and energetic Ar⁺plasma beams

Kaler

Lou

Donnelly

et al. 2017

J. Phys. D: Appl. Phys.

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Atomic layer etching (ALE) of SiO 2 was studied by alternating exposure of a 5 nm-thick SiO 2 film on Si substrate to (1) a plasma beam emanating from a cC 4 F 8 inductively coupled plasma (ICP), to grow a fluorocarbon (FC) film composed mainly of CF 2 , and (2) an energetic (130 eV) Ar + ion beam extracted from a separate Ar ICP. In situ x-ray photoelectron spectroscopy was used to analyze the chemical composition of the near-surface region, and to quantify the thickness of the FC and SiO 2 films. A very thin (3-6 Å), near self-limiting thickness CF 2-rich FC film was found to deposit on the SiO 2 surface with exposure to continuous or pulsed power C 4 F 8 plasma beams, under conditions that generated a large relative flux of CF 2. Following this, a FC film of similar composition grew at ~10 times slower rate. Exposure of the thin film to the Ar + beam led to removal of 1.9 Å SiO 2. An estimated yield of 1.3 SiO 2 molecules-per-Ar + was found for a single ALE step. The rate of 1.9 Å/cycle persisted over multiple ALE cycles, but a carbon-rich residual film did build up. This film can be removed by a brief exposure to an O 2-containing plasma beam.

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Section: Ar + Ion Bombardment Of Fluorocarbon-dosed Surfacessupporting

confidence: 92%

“…Tsutsumi et al developed an ALE SiO 2 process where O 2 plasma irradiation was used as the modified layer removal step, following fluorocarbon film deposition. They successfully suppressed a carbon-rich residual film while removing a consistent amount of SiO 2 per cycle [35].…”

Section: Ar + Ion Bombardment Of Fluorocarbon-dosed Surfacesmentioning

confidence: 99%

Atomic layer etching of silicon dioxide using alternating C₄F₈and energetic Ar⁺plasma beams

Kaler

Lou

Donnelly

et al. 2017

J. Phys. D: Appl. Phys.

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“…This layer can then be etched using Ar or O 2 plasma at low ion energy bombardment 2,3,[6][7][8][9][10][11] . However, some drifts were reported in the processes, with an increase of the etch amount per cycle (EPC) due to the fluorine contamination of the reactor walls [8][9][10]12 . Yet, Dallorto et al have shown that the effect of fluorine from the reactor wall contamination is reduced by decreasing the substrate temperature to − 10 °C and below 12 .…”

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confidence: 99%

Mechanism understanding in cryo atomic layer etching of SiO2 based upon C4F8 physisorption

Antoun

Tillocher

Lefaucheux

et al. 2021

Sci Rep

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Cryogenic Atomic Layer Etching (cryo-ALE) of SiO2 based on alternating a C4F8 molecule physisorption step and an argon plasma step, has been enhanced thanks to a better understanding of the mechanism. First, we used Quadrupole Mass spectrometry (QMS) and spectroscopic ellipsometry analyses to evaluate the residence time of physisorbed C4F8 molecules versus temperature and pressure on SiO2 surface. QMS monitoring of the SiF4 etching by-product also enabled to follow the self-limiting etching behavior. Finally, a SiO2 cryo-ALE process was proposed at a temperature of − 90 °C resulting in a very linear etch over 150 cycles and an Etch amount Per Cycle as low as 0.13 nm/cycle.

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“…Other methods for surface preparation for EBSD analysis are chemical polishing [5][6][7][8], electropolishing [9] or ion milling [10]. Plasma etching [11][12][13] is one of the methods applied for the etching of polymers [14], single crystal diamond [15], SiO 2 layers [16], carbon [17] or Ti-Al 3 Ti laminates [18]. Usually, low-pressure plasma etching requires costly vacuum equipment [14].…”

Section: Introductionmentioning

confidence: 99%

The Use of Ion Milling for Surface Preparation for EBSD Analysis

Nowak

2021

Materials

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An electron backscattered diffraction (EBSD) method provides information about the crystallographic structure of materials. However, a surface subjected to analysis needs to be well-prepared. This usually requires following a time-consuming procedure of mechanical polishing. The alternative methods of surface preparation for EBSD are performed via electropolishing or focus ion beam (FIB). In the present study, plasma etching using a glow discharge optical emission spectrometer (GD-OES) was applied for surface preparation for EBSD analysis. The obtained results revealed that plasma etching through GD-OES can be successfully used for surface preparation for EBSD analysis. However, it was also found that the plasma etching is sensitive for the alloy microstructure, i.e., the presence of intermetallic phases and precipitates such as carbides possess a different sputtering rate, resulting in non-uniform plasma etching. Preparation of the cross-section of oxidized CM247 revealed a similar problem with non-uniformity of plasma etching. The carbides and oxide scale possess a lower sputtering rate than the metallic matrix, which caused formation of relief. Based on obtained results, possible resolutions to suppress the effect of different sputtering rates are proposed.

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Atomic layer etching of SiO2 by alternating an O2 plasma with fluorocarbon film deposition

Cited by 46 publications

References 25 publications

Atomic layer etching of silicon dioxide using alternating C₄F₈and energetic Ar⁺plasma beams

Atomic layer etching of silicon dioxide using alternating C₄F₈and energetic Ar⁺plasma beams

Mechanism understanding in cryo atomic layer etching of SiO2 based upon C4F8 physisorption

The Use of Ion Milling for Surface Preparation for EBSD Analysis

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Atomic layer etching of SiO2 by alternating an O2 plasma with fluorocarbon film deposition

Cited by 46 publications

References 25 publications

Atomic layer etching of silicon dioxide using alternating C4F8and energetic Ar+plasma beams

Atomic layer etching of silicon dioxide using alternating C4F8and energetic Ar+plasma beams

Mechanism understanding in cryo atomic layer etching of SiO2 based upon C4F8 physisorption

The Use of Ion Milling for Surface Preparation for EBSD Analysis

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Product

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Atomic layer etching of silicon dioxide using alternating C₄F₈and energetic Ar⁺plasma beams

Atomic layer etching of silicon dioxide using alternating C₄F₈and energetic Ar⁺plasma beams