Thermal Atomic Layer Etching 2026 — PatSnap Eureka
Thermal Atomic Layer Etching: 2026 Technology Landscape
Thermal ALE removes material one atomic layer at a time through self-limiting thermal reactions — no plasma required. This report maps mechanisms, materials, key patent holders, and emerging directions from 2015–2025 patent and literature records, powered by PatSnap Eureka.
What Is Thermal Atomic Layer Etching?
Thermal ALE is conceptually the reverse of atomic layer deposition (ALD): where ALD adds material one monolayer at a time via self-limiting surface reactions, thermal ALE removes material one monolayer at a time through sequentially applied, self-terminating chemical steps. As established in the foundational review from Nanjing University, the process achieves isotropic atomic-level etch control based on sequential thermally driven reaction steps that are self-terminating and self-saturating — distinguishing it sharply from plasma ALE, which relies on directional ion bombardment to drive surface removal.
The canonical thermal ALE chemistry involves two half-reactions. First, surface modification: a reagent such as a fluorinating agent (HF) or oxidizing agent (O₂/O₃) converts the top monolayer of the target material into a chemically distinct, weakly bound modified layer. Second, ligand-exchange removal: a second reagent — a metal halide, organometallic ligand donor, or chlorinating agent — reacts with the modified layer to form volatile byproducts that desorb, leaving the underlying bulk material intact.
The field sits at the intersection of surface chemistry, thermodynamics, and precision semiconductor manufacturing, with strong theoretical grounding in density functional theory (DFT) simulations alongside experimental process development. According to the semiconductor equipment industry, isotropic etch precision at atomic scale is a fundamental requirement for next-generation transistor architectures.
Four Chemistry Clusters Driving Thermal ALE
Thermal ALE chemistries in this dataset fall into four distinct clusters, each addressing different material classes and process requirements.
Fluorination / Ligand-Exchange (Metal Oxides)
The most extensively documented thermal ALE mechanism in this dataset. A fluorinating agent (HF, NbF₅) converts the surface of a metal oxide into a metal fluoride or oxyfluoride layer. A ligand-exchange co-reagent (CCl₄, trimethylaluminum) then reacts with this fluorinated layer to form volatile halide complexes that desorb thermally. ASM Microchemistry demonstrated etch rates up to ~1.4 Å/cycle at 460°C for Al₂O₃ using NbF₅/CCl₄ with DFT corroboration.
~1.4 Å/cycle at 460°C — ASM Microchemistry 2021Oxidation / Chlorination (Metals)
For metallic substrates, thermal ALE proceeds via oxidation-then-chlorination. An oxidizing pulse (O₂, O₃, N₂O) converts surface metal atoms to a metal oxide layer; a subsequent chlorinating pulse (WCl₆, Cl₂) reacts with the oxide to form volatile metal oxychloride species. Intel's DFT analysis of W ALE shows O₃ as most reactive oxidant; WCl₆ removes one surface W atom per adsorption event via volatile WₓOᵧClz species. Osaka University confirmed the self-limiting etch step in Ni thermal ALE using hexafluoroacetylacetone.
Self-limiting confirmed by DFT — Intel & Osaka University 2020Halogen-Based Isotropic ALE with Pulsed Thermal Annealing
Equipment and process patents targeting production-scale implementation, using halogen adsorbates combined with controlled thermal pulses to achieve isotropic, selective etching without plasma. Lam Research's 2024 EP high-energy ALE patent extends this by using energetic particles at ≥150 eV bias after surface modification to preferentially remove the modified layer — targeting sub-10 nm 3D structure challenges such as pitch loading. A second 2024 EP patent introduces bias-voltage-controlled modification depth for directionality control.
≥150 eV bias — Lam Research High-Energy ALE EP 2024Acid Halide and Novel Reagent Chemistries
Emerging chemistry using acid halide adsorbates on hydrogenated surfaces, representing a newer reagent class beyond conventional fluorides and chlorides. Kanto Denka Kogyo's 2022 EP patent describes a three-step ALE cycle for SiO₂ and Si₃N₄: H-plasma hydrogenation of surface, chemisorption of Rf-COX acid halide on the hydrogenated surface, then a noble gas plasma pulse to stimulate desorption. Claims single atomic layer removal per cycle with halogen atoms F, Cl, Br, and I.
F, Cl, Br, I halogens — Kanto Denka Kogyo EP 2022Etch Performance & Assignee Distribution
Quantitative signals from patent and literature records in the PatSnap Eureka dataset, spanning demonstrated etch rates and IP concentration by assignee.
Demonstrated Etch Rate by Chemistry & Material
Etch-per-cycle values from key thermal ALE records; Al₂O₃ NbF₅/CCl₄ at 1.4 Å/cycle (ASM, 460°C); InAlN/GaN at 0.15 nm/cycle (SUSTech); Ge₀.₈Si₀.₂ wet-ALE at 3.1 nm/cycle (UCAS).
Patent Record Distribution by Top Assignee
Lam Research Corporation accounts for the majority of identifiable ALE patent records in this dataset — at least 6 of the identified patent filings — signalling significant IP concentration risk for new entrants.
Where Thermal ALE Is Being Deployed
Thermal ALE spans six application domains in this dataset — from advanced logic at sub-10 nm nodes to quantum computing and surface defect repair.
| Application Domain | Key Materials / Structures | Representative Organisation | Key Metric / Claim |
|---|---|---|---|
| Advanced Logic (sub-10 nm) | Ultra-thin gate dielectrics, W interconnects, FinFET channels | Lam Research, Intel, Nanjing University | Primary driver — explicitly framed as essential for <10 nm FET fabrication |
| III-V Power & RF (GaN HEMTs, LEDs) | GaN, InAlN/GaN heterostructures, AlGaN | Lam Research (KR), SUSTech | EPC 0.15 nm/cycle; improved surface roughness vs. continuous etch |
| 3D Transistors (FinFET, GAA) | SiGe, Ge nanowire/nanosheet channels | Chinese Academy of Sciences, UCAS | Sub-20 nm diameter nanowires; diameter accuracy <0.3 nm; 6.5× selectivity |
| UV / Optical Coatings | Native Al₂O₃ on UV aluminum mirrors | Jet Propulsion Laboratory / Caltech | TMA/HF chemistry at 225–300°C; LiF chamber conditioning film for UV reflectivity |
| Quantum Computing & Spintronics | Insulators, semiconductors, metals, 2D van der Waals materials | Xi'an Jiaotong University | Identified as emerging significance for spintronic device fabrication |
| Compound Semiconductor Surface Repair | GaAs — removal of plasma-etched broken layers | Southern Federal University (Russia) | Defect-free surfaces for quantum dot growth; surface remediation distinct from patterning |
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Six Frontiers Shaping the Next Phase of Thermal ALE
Based on the most recent filings and publications in this dataset, these directions signal where the field is heading — and where IP white space may exist.
High-Energy Thermal ALE for 3D Sub-10 nm Structures
Lam Research's 2024 EP patent on high-energy ALE (≥150 eV bias energy) represents an evolution beyond conventional low-bias ALE, targeting the specific challenges of pitch loading and aspect-ratio-dependent etching in 3D NAND and GAA architectures.
Directionality Control via Bias-Modulated Surface Modification
The 2024 Lam Research directionality control patent introduces voltage-tunable modification depth combined with ligand-exchange removal, potentially enabling the same hardware platform to switch between isotropic and anisotropic etch profiles — a significant capability for integration-level flexibility.
Electron Stimulation Desorption (ESD) as a Thermal-Free Pathway
Velvetch LLC's 2025 AU patent on electron-wavefront ALE uses precisely controlled electron energies from a DC plasma positive column to stimulate desorption of corrosion-layer species, entirely bypassing thermal activation. This signals a nascent direction that could lower process temperatures for thermally sensitive substrates.
Novel Acid Halide Reagent Classes for Dielectric ALE
Kanto Denka Kogyo's 2022 EP patent introduces Rf-COX acid halides (covering F, Cl, Br, I halogens) as adsorbates on H-plasma-prepared surfaces, expanding the chemical toolkit beyond the established HF/TMA and NbF₅/CCl₄ families.
What This Landscape Means for R&D and IP Strategy
Lam Research holds a commanding IP position. In this dataset, Lam Research accounts for a disproportionate share of active ALE process and equipment patents across multiple jurisdictions. Any company entering ALE equipment manufacturing must conduct thorough FTO (freedom-to-operate) analysis against Lam Research's portfolio, particularly the halogen-based isotropic thermal ALE system (WO2020/222967) and the directionality control and high-energy ALE EP filings. The PatSnap IP analytics platform can accelerate this FTO work.
Chemistry innovation is the primary white space. The dominance of equipment OEMs in process-architecture patents leaves precursor and reagent chemistry as a relatively more accessible innovation avenue. The Kanto Denka Kogyo acid halide approach and the ASM NbF₅/CCl₄ chemistry represent alternative chemical platforms with differentiated IP landscapes. Companies in advanced materials and specialty chemicals are well-positioned to enter here.
Thermal ALE for metals (W, Ni, Co) is underdeveloped relative to oxides. In this dataset, the overwhelming majority of demonstrated chemistries target metal oxides (Al₂O₃, HfO₂). Metal ALE — critical for damascene Cu/W interconnect trimming at advanced nodes — has limited demonstrated patent coverage; Intel's W study is literature, not patent. This gap represents both an R&D opportunity and a potential IP space with lower barrier to entry.
Thermal ALE process simulation and first-principles modelling are becoming prerequisite. Intel, Osaka University, Barcelona Supercomputer Centre, and ASM Microchemistry all leverage DFT or molecular dynamics to understand and predict thermal ALE mechanisms. R&D programs lacking computational chemistry capability will face longer development cycles when designing new thermal ALE processes for novel materials. The PatSnap life sciences and materials platform includes literature analysis tools to track DFT-backed process claims.
Asian academic-industrial ecosystems are building ALE competency: Chinese Academy of Sciences affiliates, Southern Federal University (Russia), and Korean university groups appear repeatedly for III-V and group-IV ALE applications. According to WIPO filing trend data, Asian jurisdictions are increasingly active in semiconductor process IP, consistent with the KR and SG filing patterns observed in this dataset.
Thermal ALE: From Concept Validation to Production Engineering
The field has moved through four distinct phases from 2015 to 2025, with increasing IP activity from equipment OEMs in the most recent period.
This timeline is derived from a limited set of patent and literature records retrieved across targeted searches. It represents a snapshot of innovation signals within this dataset only and should not be interpreted as a comprehensive view of the full industry.
Build a Complete Timeline in EurekaThermal Atomic Layer Etching — key questions answered
Thermal atomic layer etching (thermal ALE) is a precision nanofabrication technique that removes material one atomic layer at a time through sequential, self-limiting thermal-driven chemical reactions — without requiring plasma or energetic ion bombardment. It achieves isotropic atomic-level etch control based on sequential thermally driven reaction steps that are self-terminating and self-saturating.
Thermal ALE achieves isotropic atomic-level etch control based on sequential thermally driven reaction steps that are self-terminating and self-saturating — distinguishing it sharply from plasma ALE, which relies on directional ion bombardment to drive surface removal. Thermal ALE offers isotropic etch profiles, minimal surface damage, and atomic-scale thickness control that conventional plasma etch cannot match.
In this dataset, the core material classes addressed by thermal ALE include metal oxides (Al₂O₃, HfO₂, ZrO₂), metals (W tungsten, Ni nickel), III-V semiconductors (GaN, InAlN, AlGaN), and Group IV semiconductors (SiGe, Ge).
Lam Research Corporation (US) is the dominant patent filer in this dataset, with at least 6 patent records covering plasma ALE of silicon, metastable inert-gas ALE, GaN/III-V ALE, halogen-based thermal ALE systems, high-energy ALE, and directionality control. Patents appear in SG, WO, EP, and KR jurisdictions, indicating a broad international filing strategy. Any company entering ALE equipment manufacturing must conduct thorough FTO (freedom-to-operate) analysis against Lam Research's portfolio.
The dominant application driver is advanced logic semiconductor devices at sub-10 nm nodes, including ultra-thin gate dielectrics and ultra-thin channels in field-effect transistors. Other significant domains include III-V power and RF semiconductor devices (GaN HEMTs and LEDs), advanced 3D transistor architectures (FinFET, Gate-All-Around), UV/optical coatings and photonics, quantum computing and spintronics, and compound semiconductor surface defect repair.
Based on the most recent filings and publications (2022–2025), emerging directions include: high-energy thermal ALE for 3D sub-10 nm structures (Lam Research 2024 EP patent using ≥150 eV bias energy); directionality control via bias-modulated surface modification; electron stimulation desorption (ESD) as a thermal-free removal mechanism (Velvetch LLC 2025 AU patent); novel acid halide reagent classes for dielectric ALE; 2D van der Waals material ALE for MoS₂ and WSe₂; and selective area and self-aligned integration schemes.
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References
- Thermal Atomic Layer Etching: Mechanism, Materials and Prospects — Nanjing University, 2018
- Mechanism of Thermal Atomic Layer Etch of W Metal Using Sequential Oxidation and Chlorination: A First-Principles Study — Intel Corporation, 2020
- Origin of Enhanced Thermal Atomic Layer Etching of Amorphous HfO₂ — Barcelona Supercomputer Centre, 2021
- Thermal Atomic Layer Etching of Aluminum Oxide (Al₂O₃) Using Sequential Exposures of Niobium Pentafluoride (NbF₅) and Carbon Tetrachloride (CCl₄) — ASM Microchemistry Oy, 2021
- Enhanced Atomic Layer Etching of Native Aluminum Oxide for Ultraviolet Optical Applications — Jet Propulsion Laboratory / California Institute of Technology, 2017
- Self-limiting Processes in Thermal Atomic Layer Etching of Nickel by Hexafluoroacetylacetone — Osaka University, 2020
- Atomic Layer Etching Using Acid Halide — Kanto Denka Kogyo Co., Ltd., EP 2022 (active)
- Atomic Layer ETCH Systems for Selectively Etching with Halogen-Based Compounds — Lam Research Corporation, WO 2020
- High Energy Atomic Layer Etching — Lam Research Corporation, EP 2024 (active)
- Control of Directionality in Atomic Layer Etching — Lam Research Corporation, EP 2024 (active)
- Atomic Layer Etching by Electron Wavefront — Velvetch LLC, AU 2025 (active)
- Atomic Layer Etching of GaN and Other III-V Materials — Lam Research Corporation, KR 2016 (active)
- A Novel Dry Selective Isotropic Atomic Layer Etching of SiGe for Manufacturing Vertical Nanowire Array with Diameter Less than 20 nm — Institute of Microelectronics, Chinese Academy of Sciences, 2020
- Investigation on Ge₀.₈Si₀.₂-Selective Atomic Layer Wet-Etching of Ge for Vertical Gate-All-Around Nanodevice — University of Chinese Academy of Sciences, 2021
- The Atomic Layer Etching Technique with Surface Treatment Function for InAlN/GaN Heterostructure — Southern University of Science and Technology, 2022
- Recent Progress of Atomic Layer Technology in Spintronics: Mechanism, Materials and Prospects — Xi'an Jiaotong University, 2022
- Application of the Atomic Layer Etching Technique to Remove Broken Layers after Plasma-Etched GaAs Surface Treatment — Southern Federal University, 2020
- Cyclic Etch/Passivation-Deposition as an All-Spatial Concept toward High-Rate Room Temperature Atomic Layer Etching — TNO, 2015
- Self-Aligned Thin-Film Patterning by Area-Selective Etching of Polymers — University of Helsinki, 2021
- WIPO — World Intellectual Property Organization (semiconductor filing trend data)
- SEMI — Semiconductor Equipment and Materials International
All data and statistics on this page are sourced from the references above and from PatSnap's proprietary innovation intelligence platform. This landscape is derived from a limited set of patent and literature records retrieved across targeted searches and represents a snapshot of innovation signals within this dataset only.
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