Resist-Free Stencil Deposition for Low-Loss Superconducting Circuits and Qubits (Part 1)

Conventional liftoff techniques using organic resists are widely employed for Josephson-junction fabrication, but they can degrade metal quality and leave behind residues that are believed to limit qubit coherence. To investigate the impact of resist-based fabrication on superconducting circuits, we developed a resist-free process using a silicon nitride stencil mask, enabling wafer-scale junction deposition without organic resists.

 

In the first part of this two-part talk, we present our fabrication method of the silicon nitride stencil mask and its integration into wafer-scale deposition. We describe the design of the resonators used for comparing the loss between stencil-deposited and liftoff metals, and we present corresponding material characterization and measurement results.