Extensible quantum computing architectures require a large array of quantum bits operating
with low error rates. A quantum processor based on superconducting devices can be scaled
up by stacking microchips that perform wiring, shielding, and computational functionalities.
In this article, we demonstrate a vacuum thermocompression bonding technology that
utilizes thin indium films as a welding agent to attach pairs of lithographically patterned
chips. At 10 mK, we find a specific dc bond resistance of 49.2 μΩ cm 2. We show good …