Hi everyone, I am looking for the spec of the max. allowed current density of the metal layers (and potentially the resistors)? Please send a pointer to the respective document, thanks!

There were no such numbers in SkyWater documentation, but I worked out some likely numbers, as it's just aluminum so should be possible to get the values knowing the material and dimensions. If @User has a copy of the numbers I calculated, he could post them. Otherwise I need to look up where I wrote them down, which I can do in a few hours from now.

I lost those numbers. Sorry. I think the PDK info page has current density for the resistors though

1mA/um should be reasonably safe (I assume the thickness is a good fraction of a micron).

I just happened to come across my notes on the calculations that Weston and I did. For good measure, I put them in a public document here: https://docs.google.com/spreadsheets/d/1oL6ldkQdLu-4FEQE0lX6BcgbqzYfNnd1XA8vERe0vpE/edit#gid=1059412464 (sheet labeled "Layer Resistances and Capacitances") The numbers are based on rules from other processes pro-rated to the specific thicknesses of the metal layers in the SkyWater process. I don't have any relevant information about electromigration in Titanium Nitride, so I don't have a number for local interconnect. But for the other metal layers, the values are: Metals 1 and 2: 0.65 mA/um Metals 3 and 4: 1.50 mA/um Metal 5: 2.30 mA/um