Quantum technologies, especially quantum computing, will play a groundbreaking role in technology, economy, and social developments and are therefore considered to be a game changer in various branches. The core element for quantum computation are quantum bits (qubits), which can be realized by superconducting implementations. Nowadays a promising and commonly used qubit type is a transmon. It consists of one or two Josephson junctions which are shunted by a big capacitance. In most cases the qubits are integrated with coplanar waveguide resonators and transmission lines to provide a low loss read out. Recently, scaling up the number of qubits is the main task for realizing quantum computers and, thus, wafer-scale fabrication technologies for the qubits in combination with beyond 2D integration technologies are essential.
In our presentation, we provide latest results on our research on wafer-scale fabrication and characterization of the superconducting quantum circuits with a special emphasis on the transmon qubit environment and integration technologies. We discuss different approaches on fabricating coplanar waveguide resonators and evaluate their quality factors. Within the scope of scalability and increased packaging density, we present aluminum air bridges as a part of our integration technology. We discuss their fabrication process and demonstrate their superconducting properties as well as their implementation into the superconducting quantum circuits.