On-chip stencil lithography for superconducting qubits

Improvements in circuit design and, more recently, in materials and surface cleaning have contributed to a rapid development of coherent superconducting qubits. However, organic resists commonly used for shadow evaporation of Josephson junctions (JJs) pose limitations due to residual contamination, poor thermal stability, and compatibility under typical surface-cleaning conditions. To provide an alternative, we developed an inorganic SiO2/Si3N4 on-chip stencil lithography mask for JJ fabrication. The stencil mask is resilient to aggressive cleaning agents and it withstands high temperatures up to 1200 °C, thereby opening new avenues for JJ material exploration and interface optimization. To validate the concept, we performed shadow evaporation of Al-based transmon qubits followed by stencil mask liftoff using vapor hydrofluoric acid, which selectively etches SiO2. We demonstrate an average T1≈75±11 μs over a 200 MHz frequency range across multiple cooldowns for one device, and T1≈44±8 μs for a second device. These results confirm the compatibility of stencil lithography with state-of-the-art superconducting quantum devices and motivate further investigations into materials engineering, film deposition, and surface cleaning techniques.

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Publication Details

Journal
Applied Physics Reviews
Published
2026-04-06
DOI
https://doi.org/10.1063/5.0307532
Primary Topic
Advancements in Photolithography Techniques
Type
article
Field-Weighted Citation Impact
0.00

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article

On-chip stencil lithography for superconducting qubits

Mathieu Féchant, Roudy Hanna, Niels R. Tas, Michael Schleenvoigt et al.
Applied Physics Reviews
Advancements in Photolithography Techniques
article

On-chip stencil lithography for superconducting qubits

Mathieu Féchant, Roudy Hanna, Niels R. Tas, Michael Schleenvoigt, Simon Geisert, Jin Hee Bae, M. E. Field, Abdur Rehman Jalil, Thomas J. Smart, Benjamin Bennemann, Albert Hertel, Erwin Berenschot, Gary A. Steele, Peter Schüffelgen, Kaycee Underwood, Martin Spiecker, Detlev Grützmacher, Christian Dickel, Ioan M. Pop, Tobias Schmitt, Sören Ihssen, Nicolas Zapata, Umut Kocak, Matteo Arfini
article en

Abstract

Improvements in circuit design and, more recently, in materials and surface cleaning have contributed to a rapid development of coherent superconducting qubits. However, organic resists commonly used for shadow evaporation of Josephson junctions (JJs) pose limitations due to residual contamination, poor thermal stability, and compatibility under typical surface-cleaning conditions. To provide an alternative, we developed an inorganic SiO2/Si3N4 on-chip stencil lithography mask for JJ fabrication. The stencil mask is resilient to aggressive cleaning agents and it withstands high temperatures up to 1200 °C, thereby opening new avenues for JJ material exploration and interface optimization. To validate the concept, we performed shadow evaporation of Al-based transmon qubits followed by stencil mask liftoff using vapor hydrofluoric acid, which selectively etches SiO2. We demonstrate an average T1≈75±11 μs over a 200 MHz frequency range across multiple cooldowns for one device, and T1≈44±8 μs for a second device. These results confirm the compatibility of stencil lithography with state-of-the-art superconducting quantum devices and motivate further investigations into materials engineering, film deposition, and surface cleaning techniques.

Applied Physics ReviewsVol. 13(2)
University of Stuttgart (DE), Karlsruhe Institute of Technology (DE), TH Köln - University of Applied Sciences (DE), University of Cologne (DE), University of Würzburg (DE), Karlsruhe University of Education (DE), Kerntechnische Entsorgung Karlsruhe (Germany) (DE), Jülich Aachen Research Alliance (DE), RWTH Aachen University (DE), University of Twente (NL), Delft University of Technology (NL)
Deutsche Forschungsgemeinschaft, Bundesministerium für Bildung und Forschung, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, HORIZON EUROPE European Research Council
Openalex Percentile: Top 100%
Advancements in Photolithography Techniques
DOIOpen Access PDFOpenAlex
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