Perspectives in nanoscale plasma etching: what are the ultimate limits?

Marchack, Nathan; Chang, Jane P.

doi:10.1088/0022-3727/44/17/174011

Cited by 43 publications

(37 citation statements)

References 127 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Subsequently, Yeom's group developed this approach to perform Si ALE using the same kind of Cl 2 exposure in combination with energetic Ar neutrals obtained by the low-angle forward reflection neutral beam technique. 40,41,90,91 They observed a self-limited Si etch rate of a monolayer per cycle for both Si (100) and Si (111) orientations when Cl 2 and Ar neutrals were supplied above the critical dose values, and surface roughness that remained very low and comparable to a reference sample without ALE.…”

Section: Iii-v: Gaasmentioning

confidence: 99%

“…Molecular dynamics simulations of Si ALE by Athavale et al 85 using 50 eV argon ion bombardment of Si(100) passivated with a monolayer of adsorbed chlorine showed that 93% of etched Si originated from the top silicon layer and 7% from the underlayer. For 50 eV Ar + ions the Si reaction yield was 0.172 Si atoms removed per ion, 84% in the form of SiCl, 8% elemental Si and 8% as SiCl 2 . These results nicely demonstrate the concept of the ALE window, since this yield is higher than expected for physical sputtering.…”

Section: Iii-v: Gaasmentioning

confidence: 99%

“…This approach has significant potential to speed up processing relative to ALE based on halogenation of Si using simply gaseous halogens, e.g. Cl 2 .…”

Section: Iii-v: Gaasmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8] An etching method corresponding to Atomic Layer Deposition (ALD), i.e. Atomic Layer Etching (ALE), is expected to satisfy these needs as critical dimensions continue to shrink below the 10 nm scale.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Atomic Layer Etching at the Tipping Point: An Overview

Oehrlein

Metzler

2015

ECS J. Solid State Sci. Technol.

206

162

View full text Add to dashboard Cite

The ability to achieve near-atomic precision in etching different materials when transferring lithographically defined templates is a requirement of increasing importance for nanoscale structure fabrication in the semiconductor and related industries. The use of ultra-thin gate dielectrics, ultra thin channels, and sub-20 nm film thicknesses in field effect transistors and other devices requires near-atomic scale etching control and selectivity. There is an emerging consensus that as critical dimensions approach the sub-10 nm scale, the need for an etching method corresponding to Atomic Layer Deposition (ALD), i.e. Atomic Layer Etching (ALE), has become essential, and that the more than 30-year quest to complement/replace continuous directional plasma etching (PE) methods for critical applications by a sequence of individual, self-limited surface reaction steps has reached a crucial stage. A key advantage of this approach relative to continuous PE is that it enables optimization of the individual steps with regard to reactant adsorption, self-limited etching, selectivity relative to other materials, and damage of critical surface layers. In this overview we present basic approaches to ALE of materials, discuss similarities/crucial differences relative to thermal and plasma-enhanced ALD, and then review selected results on ALE of materials aimed at pattern transfer. The overview concludes with a discussion of opportunities and challenges ahead. A requirement of increasing importance for nanoscale device fabrication is the ability to achieve atomic scale etching control and materials selectivity during pattern transfer.1-8 An etching method corresponding to Atomic Layer Deposition (ALD), i.e. Atomic Layer Etching (ALE), is expected to satisfy these needs as critical dimensions continue to shrink below the 10 nm scale.Demonstrations of self-limited dry etching methods capable of near-atomic resolution have a long history in the dry etching community and a brief review will be presented below. Key challenges for these approaches have been specialized equipment, long process times and low throughput.9,10 However, a recent demonstration using a commercial plasma etch tool 10 and activities within the dry etching community 11 provide indications that the situation has changed, and that we may have reached for ALE the Tipping Point which Gladwell defined as the "the moment of critical mass, the threshold, the boiling point" when "ideas and products and messages and behaviors spread like viruses do".12 This is due to several factors, including unprecedented demands on dry etching technology introduced by the semiconductor device evolution according to Moore's law that can be satisfied by atomic layer etching, advanced capabilities in plasma etch, and the existence of a critical level of information on plasma etch and ALD methods as applied in the semiconductor fabrication space.In this article we will provide a review of background of these approaches, and focus on issues that have to be overcome for widespread implement...

show abstract

Section: Iii-v: Gaasmentioning

confidence: 99%

Section: Iii-v: Gaasmentioning

confidence: 99%

“…This approach has significant potential to speed up processing relative to ALE based on halogenation of Si using simply gaseous halogens, e.g. Cl 2 .…”

Section: Iii-v: Gaasmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Atomic Layer Etching at the Tipping Point: An Overview

Oehrlein

Metzler

2015

ECS J. Solid State Sci. Technol.

206

162

View full text Add to dashboard Cite

show abstract

“…Atomic layer etching (ALE) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] refers to an etching process where each atomic layer of the surface of a substrate, such as crystalline Si, is etched in a single cycle. In such a process, one could specify the exact number of atomic layers to be removed from the substrate, thereby ensuring atomic level accuracy of the etched depth.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Atomic Layer Oxidation of Silicon by Oxygen Gas Cluster Beams

Mizotani

Isobe

Karahashi

et al. 2015

Plasma and Fusion Research

View full text Add to dashboard Cite

A gas cluster is a collection of atoms or molecules weakly bound by van der Waals forces. Gas clusters may form by the adiabatic expansion of gases. In this study, it is demonstrated by molecular dynamics simulations that a low-energy beam of oxygen gas clusters may be used to oxidize the top surface layer of silicon (Si) substrates without affecting its deeper layers. An incident oxygen gas cluster with sufficiently low incident energy may stick to the Si surface and expose a large number of oxygen molecules to the surface Si atoms for extended periods until the cluster sublimates. This may cause the formation of Si-O bonds only on the top Si surface. This is in contrast to the oxidation of Si by oxygen ion beams or plasmas, where deeper layers of the Si surface are typically oxidized by the energetic incident oxygen ions. An oxidized single Si layer may be chemically removed; therefore, this nearly single-layer oxidation process by oxygen gas cluster beams may lead to the development of a new atomic layer etching technology for Si.

show abstract

Relationship between edge roughness in mask pattern and charging in plasma etching

Zhang

2019

Plasma Processes & Polymers

View full text Add to dashboard Cite

The edge roughness (ER) developed in the mask pattern during the plasma etching process harms the perfect pattern transformation from mask to substrate. To understand and ultimately manipulate plasma-induced ER, this study investigated the interplay between charging and nanoscale roughness of an isolated rough mask hole in the plasma etching process using a modeling framework, which consisted of a surface etching module, a surface charging module, and a profile evolution module. Specifically, on the one hand, the distributions of the spatial electric field (E-field) and etching rate were simulated for the rough mask surface being etched. It is revealed that the distribution of the etching rate is similar with that of E-field clinging to the mask surface, and both of them reach their maximum strength around the mask hole edge and gradually becomes uniform/nonuniform with the decrease of the value of the dominant amplitude/wavelength of roughness; on the other hand, a string algorithm was used to simulate the evolution rule for a rough profile of a mask hole with etching time under various values of roughness parameters. The simulated evolution of the profile has good agreement with experimental observation. The charging effect contributes to the enhancement of the root mean square roughness. Additionally, the influence of roughness parameters on the charging time versus root mean square was also examined. The mechanism behind these results was analyzed systematically. This study will greatly contribute toward improving the physical and chemical properties of the mask or optimizing the etching technique.K E Y W O R D S charging, particle simulation, plasma etching, roughness

show abstract

Perspectives in nanoscale plasma etching: what are the ultimate limits?

Cited by 43 publications

References 127 publications

Atomic Layer Etching at the Tipping Point: An Overview

Atomic Layer Etching at the Tipping Point: An Overview

Numerical Simulation of Atomic Layer Oxidation of Silicon by Oxygen Gas Cluster Beams

Relationship between edge roughness in mask pattern and charging in plasma etching

Contact Info

Product

Resources

About