Disclaimer: No where close to an expert. My understanding of the more popular superconducting types is that a bit of superconductor is connected up to a juncti

Disclaimer: No where close to an expert. My understanding of the more popular superconducting types is that a bit of superconductor is connected up to a junction that allows quantum tunneling of electron pairs. The number of electron pairs that tunnel through the junction determines the state and the state is read out by an exotic electrometer. As for how the chip itself is made, as far as I know it's a relative standard lithography process except with added superconducting layers.