  As superconducting quantum processors increase in complexity, techniques to
overcome constraints on frequency crowding are needed. The recently developed
method of laser-annealing provides an effective post-fabrication method to
adjust the frequency of superconducting qubits. Here, we present an automated
laser-annealing apparatus based on conventional microscopy components and
demonstrate preservation of highly coherent transmons. In one case, we observe
a two-fold increase in coherence after laser-annealing and perform noise
spectroscopy on this qubit to investigate the change in defect features, in
particular two-level system defects. Finally, we present a local heating model
as well as demonstrate aging stability for laser-annealing on the wafer scale.
Our work constitutes an important first step towards both understanding the
underlying physical mechanism and scaling up laser-annealing of superconducting
qubits.
