So here is an update on the mask I was designing to do some qubit experiments:
This mask should allow us to do various things. There are some coplanar resonator structures and some time-domain coherence chips here.
I’ve had to put anodisation bridges and anod-layer cuts all over the place. This is because the entire bottom layer of Niobium needs to be anodised anywhere where a junction region is defined. Anodisation requires electrical contact between regions which can be floating (such as where you have qubits). So you must join up these regions to the main bottom wiring layer and then cut them later in the later process step. I really hope I didn’t forget any pieces!
After all that mask designing, some cake is required. Here are some delicious cakes I baked a little while ago: