SC-1 Etching of Niobium and Titanium Nitride Thin Films

Adri\'an Guti\'errez-Cruz; Alberto Ronzani; Harshad Mishra; Jani M. Taskinen; Jorden Senior; K. A. C. Rathnathilaka; Kestutis Grigoras; Rishabh Upadhyay; Tuomas Vaimala

arxiv: 2605.28343 · v1 · pith:EG4TKYWXnew · submitted 2026-05-27 · ❄️ cond-mat.mtrl-sci · cond-mat.mes-hall

SC-1 Etching of Niobium and Titanium Nitride Thin Films

Adri\'an Guti\'errez-Cruz , K. A. C. Rathnathilaka , Jani M. Taskinen , Tuomas Vaimala , Kestutis Grigoras , Harshad Mishra , Rishabh Upadhyay , Jorden Senior

show 1 more author

Alberto Ronzani

This is my paper

Pith reviewed 2026-06-29 11:17 UTC · model grok-4.3

classification ❄️ cond-mat.mtrl-sci cond-mat.mes-hall

keywords niobiumtitanium nitridewet etchingSC-1thin filmsmicroelectronics fabricationpatterningnative oxide

0 comments

The pith

SC-1 solution etches niobium and titanium nitride thin films at controllable rates with high selectivity.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper establishes that the Standard Cleaning 1 solution serves as a viable wet etchant for patterning niobium and titanium nitride films. It tracks how etch depth changes with time and checks the resulting surfaces with electron and atomic force microscopy. The work ties the observed behavior to native oxides and the films' internal structure. A reader would care because this approach sidesteps the plasma damage that dry etching often leaves behind in microelectronics processing. If the rates and selectivity hold up, the method offers a simpler and safer route to define these materials in devices.

Core claim

The authors demonstrate a wet etching alternative for the patterning of niobium and titanium nitride thin films using the Standard Cleaning 1 solution. They characterize the etching process through its time-evolution dynamics, supported by scanning-electron and atomic force microscopy assessment of the etched film morphology. The results suggest etch dynamics that are linked to native oxides and film microstructure. Overall, the manageable etch rates, the safe operation and the high material selectivity are attractive for practical use in microelectronics fabrication.

What carries the argument

The SC-1 wet etching process, which removes material through timed chemical reaction with the solution while leaving other layers largely intact.

If this is right

Etch depth can be set by controlling immersion time because the rate follows a predictable time dependence.
High selectivity allows removal of the target film while preserving underlying or adjacent layers.
Absence of plasma reduces collateral damage that can degrade electrical performance in finished devices.
Safe handling and manageable rates make the process compatible with standard cleanroom workflows.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

The same solution might pattern related superconducting or barrier films if their native oxides respond similarly.
Device-scale tests on actual circuit layouts would reveal whether edge profiles meet lithography tolerances.
Integration with existing cleaning steps could reduce the total number of process modules needed.

Load-bearing premise

The etch rates, selectivity, and surface quality seen in test samples will remain consistent enough for direct use on full device structures without extra tuning.

What would settle it

Fabrication runs on actual device wafers where SC-1 produces uneven removal, undercutting, or residue that prevents working circuits would show the process is not yet ready for practical patterning.

Figures

Figures reproduced from arXiv: 2605.28343 by Adri\'an Guti\'errez-Cruz, Alberto Ronzani, Harshad Mishra, Jani M. Taskinen, Jorden Senior, K. A. C. Rathnathilaka, Kestutis Grigoras, Rishabh Upadhyay, Tuomas Vaimala.

**Figure 2.** Figure 2: Etched depths estimated by cross-sectional SEM imaging as a function of etching time [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗

**Figure 3.** Figure 3: Cross-sectional SEM images of the etched area from the Nb and TiN films when the [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗

read the original abstract

Dry etching techniques, ubiquitous in microelectronics fabrication, often result in challenging levels of undesired collateral plasma-induced damage. In this work, we demonstrate a wet etching alternative for the patterning of niobium (Nb) and titanium nitride (TiN) thin films using the Standard Cleaning 1 (SC-1) solution. We characterize the etching process through its time-evolution dynamics, supported by scanning-electron and atomic force microscopy assessment of the etched film morphology. The results suggest etch dynamics that are linked to native oxides and film microstructure. Overall, the manageable etch rates, the safe operation and the high material selectivity are attractive for practical use in microelectronics fabrication.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

SC-1 gives usable wet-etch rates on Nb and TiN films with decent selectivity, but this stays a narrow process note rather than a deeper materials study.

read the letter

The main takeaway is that SC-1 solution etches niobium and titanium nitride thin films at practical rates while avoiding plasma damage from dry processes. The authors show time-dependent etch behavior and post-etch surface images from SEM and AFM, and they tie the results to native oxides and microstructure. That framing is reasonable for these materials.

The work does what it sets out to do: it documents a wet alternative that is already familiar in fab lines, so the barrier to adoption is low. Manageable rates, safety, and selectivity are the selling points, and the experimental record supports those claims without obvious internal contradictions.

The soft spots are mostly about scope and depth. The data appear descriptive rather than heavily quantified with error bars or multiple film batches, and there is no direct head-to-head with other wet etches or device-level testing. Reproducibility across different deposition conditions is left for later work. These are normal limits for a focused experimental report, not fatal gaps.

This paper is for process engineers who need wet-etch options for superconducting or microelectronics films. A reader already working with Nb or TiN will get concrete numbers and images to try. It will not change models or open new research directions.

I would send it for peer review. The demonstration is narrow but the execution looks honest and the practical angle is clear enough to be worth referee time.

Referee Report

2 major / 1 minor

Summary. The manuscript claims to demonstrate SC-1 wet etching as a low-damage alternative to dry etching for patterning Nb and TiN thin films. It reports time-dependent etch behavior characterized by SEM and AFM morphology assessment, links the dynamics to native oxides and film microstructure, and highlights manageable rates, operational safety, and material selectivity as advantages for microelectronics fabrication.

Significance. If the demonstration is supported by reproducible quantitative data, the work would supply a simple, plasma-free patterning route for these superconducting and barrier materials, potentially reducing collateral damage in device fabrication flows. As a modest experimental note rather than a fully validated process, its primary value would lie in process exploration rather than immediate production adoption.

major comments (2)

[Abstract] Abstract and main text: the central claim of a demonstrated etching process with 'manageable etch rates' and 'high material selectivity' is asserted without any reported numerical etch rates, uncertainties, or selectivity ratios, leaving the practical-utility framing unsupported by visible quantitative evidence.
[Results] The description of time-evolution dynamics and morphology results lacks error bars, number of replicates, or detailed protocols (solution concentration, temperature, agitation), which are load-bearing for assessing reproducibility of the reported etch behavior.

minor comments (1)

[Figures] Figure captions should explicitly state scale bars, measurement conditions, and whether images are representative or averaged.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the detailed review and constructive comments on our manuscript. We address each major comment below and will incorporate revisions to strengthen the quantitative support and reproducibility details.

read point-by-point responses

Referee: [Abstract] Abstract and main text: the central claim of a demonstrated etching process with 'manageable etch rates' and 'high material selectivity' is asserted without any reported numerical etch rates, uncertainties, or selectivity ratios, leaving the practical-utility framing unsupported by visible quantitative evidence.

Authors: We agree that the claims regarding manageable etch rates and high material selectivity would be better supported by explicit numerical values. In the revised manuscript, we will add the measured etch rates for Nb and TiN (including uncertainties from replicate measurements) and the corresponding selectivity ratios to other materials in the fabrication stack, drawn directly from the experimental data already obtained. revision: yes
Referee: [Results] The description of time-evolution dynamics and morphology results lacks error bars, number of replicates, or detailed protocols (solution concentration, temperature, agitation), which are load-bearing for assessing reproducibility of the reported etch behavior.

Authors: The referee correctly identifies that these experimental details are essential. We will revise the Results section to specify the SC-1 solution concentration and preparation, the controlled temperature, the agitation method used, the number of independent replicates for each time point, and to include error bars on all time-evolution and morphology data presented in figures and text. revision: yes

Circularity Check

0 steps flagged

No significant circularity; purely descriptive experimental report

full rationale

The paper presents an experimental demonstration of SC-1 wet etching for Nb and TiN thin films, reporting time-dependent etch rates, selectivity, and post-etch morphology via SEM/AFM. No equations, derivations, fitted parameters, predictions, or mathematical claims appear anywhere in the text. The central claim is supported directly by the characterization data without any reduction to self-defined quantities, self-citations, or ansatzes. This is a standard empirical materials report with no load-bearing logical steps that could exhibit circularity.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

No mathematical model, free parameters, axioms, or invented entities are present; the paper is an experimental demonstration report.

pith-pipeline@v0.9.1-grok · 5690 in / 990 out tokens · 32629 ms · 2026-06-29T11:17:52.102065+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

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Kim S, Mohan J, Kim H, Hwang S, Kim N, Jung Y, Sahota A, Kim K, Yu H, Cha P, Young C D, Choi R, Ahn J and Kim J 2020Materials132968 8 Supplementary Information for: SC-1 Etching of Niobium and Titanium Nitride Thin Films S1 Example of challenging selectivity in a dry etching process Reactive ion etching was tested for the patterning of superconducting Nb ...

[1] [1]

Nojiri K 2015Dry Etching Technology for Semiconductors1st ed (Springer)

[2] [2]

Sawin H H 1994Microelectronic Engineering2315–21

[3] [3]

Lee C G N, Kanarik K J and Gottscho R A 2014Journal of Physics D: Applied Physics47 273001

[4] [4]

Eriguchi K 2017Journal of Physics D: Applied Physics50333001

[5] [5]

Wang J, Houwman E, Salm C, Nguyen M, Vergeer K and Schmitz J 2017Microelectronic Engineering17713–18

[6] [6]

See Supplementary Information for additional data

[7] [7]

Kern W and Puotinen D A 1970RCA Review31187–206

[8] [8]

Sun X, Mao S, Lu C, Geng D, Li L, Wang G and Zhao C 2024Journal of Materials Science: Materials in Electronics351–7

[9] [9]

Wittmer M and Melchior H 1982Thin Solid Films93397–405

[10] [10]

Gr¨ onberg L, Kiviranta M, Vesterinen V, Lehtinen J, Simbierowicz S, Luomahaara J, Prunnila M and Hassel J 2017Superconductor Science and Technology30125016

[11] [11]

Hott R, Kleiner R, Wolf T and Zwicknagl G 2016Encyclopedia of Applied Physics: Review on Superconducting Materials1st ed (Wiley-VCH)

[12] [12]

Bi J, Lin Y, Zhang Q, Liu Z, Zhang Z, Zhang R, Yao X, Chen G, Liu H, Huang Y, Sun Y, Zhang H, Sun Z, Xiao S and Cao Y 2024Nano Letters247451–7457

[13] [13]

Zhang T, Bi J, Wang X, Li P, Zhang R, Zhai R, Guo Z, Ning C, Yan K, Zhang S, Peng S, Zhang J, Huang L and Cao Y 2025Physical Review B112045403

[14] [14]

Verhaverbeke S and Parker J W 1997MRS Online Proceedings Library477447–458

[15] [15]

Deng H, Song Z, Gao R, Xia T, Bao F, Jiang X, Ku H S, Li Z, Ma X, Qin J, Sun H, Tang C, Wang T, Wu F, Yu W, Zhang G, Zhang X, Zhou J, Zhu X, Shi Y, Zhao H H and Deng C 2023Physical Review Applied19024013

[16] [16]

Vereecke G, De Coster H, Van Alphen S, Carolan P, Bender H, Willems K, Ragnarsson L ˚A, Van Dorpe P, Horiguchi N and Holsteyns F 2018Microelectronic Engineering20056–61

[17] [17]

Burns D W 2011 Mems wet-etch processes and proceduresMEMS Materials and Processes Handbook(Springer) pp 457–665

2011

[18] [18]

Liu Y X, Kamei T, Endo K, O’uchi S, Tsukada J, Yamauchi H, Hayashida T, Ishikawa Y, Matsukawa T, Sakamoto K, Ogura A and Masahara M 2009 Nanoscale tin wet etching and its application for finfet fabricationInternational Semiconductor Device Research Symposium (IEEE) pp 1–2

2009

[19] [19]

Guti´ errez-Cruz A 2024Josephson Field Effect Transistor Channel FabricationMaster’s thesis Aalto University, Finland 7

[20] [20]

Williams K R, Gupta K and Wasilik M 2003Journal of Microelectromechanical Systems12 761–778

[21] [21]

Lichtenberger A W, Lea D M and Lloyd F L 1993IEEE Transactions on Applied Supercon- ductivity32191–2196

[22] [22]

Walker P and Tarn W H 1991CRC Handbook of Metal Etchants1st ed (CRC Press)

[23] [23]

Williams B H 1928Transactions of the Faraday Society24245–255

[24] [24]

Lindau I and Spicer W E 1974Journal of Applied Physics453720–3725

[25] [25]

Jia X Q, Kang L, Liu X Y, Wang Z H, Jin B B, Mi S B, Chen J, Xu W W and Wu P H 2012 IEEE Transactions on Applied Superconductivity232300704

2012

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Verjauw J, Potoˇ cnik A, Mongillo M, Acharya R, Mohiyaddin F, Simion G, Pacco A, Ivanov T, Wan D, Vanleenhove A, Souriau L, Jussot J, Thiam A, Swerts J, Piao X, Couet S, Heyns M, Govoreanu B and Radu I 2021Physical Review Applied16014018

[27] [27]

Bakulin A, Chumakova L and Kulkova S 2025Physical Mesomechanics2855–65

[28] [28]

Polyakova I G and H¨ ubert T 2001Surface and Coatings Technology14155–61

[29] [29]

Chen H Y and Lu F H 2005Journal of Vacuum Science & Technology A231006–1009

[30] [30]

Mahieu S, Depla D and De Gryse R 2008 Modelling the growth of transition metal nitrides Journal of Physics: Conference Seriesvol 100 (IOP Publishing) p 082003

2008

[31] [31]

Banerjee R, Chandra R and Ayyub P 2002Thin Solid Films40564–72

[32] [32]

Isaev A G and Rogozhin A E 2025Russian Microelectronics54265–274

[33] [33]

Qi R, Pan L, Feng Y, Wu J, Li W and Wang Z 2020Results in Physics19103416

[34] [34]

Fang J, Li C, Liu F, Hou H, Zhang X, Zhang Q, Yang L, Xu C and Song Z 2024Materials Today Communications38108111

[35] [35]

Xue H, Zhang Z, Ai J, Li C, Li B, Zhao Y and Wang A 2024Ceramics International50 25978–25987

[36] [36]

Grigoras K, Yurttag¨ ul N, Kaikkonen J P, Mannila E T, Eskelinen P, Lozano D P, Li H X, Rommel M, Shiri D, Tiencken N, Simbierowicz S, Ronzani A, H¨ atinen J, Datta D, Vesterinen V, Gr¨ onberg L, Bizn´ arov´ a J, Roudsari A F, Kosen S, Osman A, Prunnila M, Hassel J, Bylander J and Govenius J 2022IEEE Transactions on Quantum Engineering31–10

[37] [37]

Kim S, Mohan J, Kim H, Hwang S, Kim N, Jung Y, Sahota A, Kim K, Yu H, Cha P, Young C D, Choi R, Ahn J and Kim J 2020Materials132968 8 Supplementary Information for: SC-1 Etching of Niobium and Titanium Nitride Thin Films S1 Example of challenging selectivity in a dry etching process Reactive ion etching was tested for the patterning of superconducting Nb ...