Frequency trimming of superconducting fixed-frequency qubits

There has been significant progress to increase the number of superconducting fixed-frequency qubits for multi-qubit gates. The variations in fabrication limits the precision in qubit frequency to within ~ 200 MHz of the design value [1], which could lead to undesired frequency crowding. We developed a frequency trimming process to correct the frequencies of the measured qubits. The frequency trimming involves first a chemical process to remove all on-chip wirebonds, followed by lithography and dry etch to trench the dielectric substrate near the qubit to tune the frequency to the target design value. We present fabrication process details, simulations, and qubit measurements.

[1] S. Rosenblatt et al. , Variability metrics in Josephson Junction fabrication for Quantum Computing circuits, in Proceedings of the APS March Meeting, New Orleans (2017).