Tim Edwards

11/22/2020, 3:46 AM
@User: Inductors would best be done on the redistribution layer, but we have no plans for that for this tapeout, and everything is running late enough that I will probably work on the post-processing layout after tape-in. The inductors under the "Devices 1" menu are broken; the final devices that we were able to pull from the SkyWater libraries are on Metal 3 and look like they belong to an older variant of the process (no longer supported) that had three layers of metal with a thick metal3. It is well worth scaling those up a bit and recasting them to Metal 5 and characterizing them. The main problem will be the effect of having large bump bonds on top of the whole layout.

Chris Jones

11/23/2020, 12:22 AM
Yes, the bumps and redistribution layer metal would ruin any inductors that are under them, and alter the inductance if they are close but not underneath. If the design of the redistribution routing is availble and is not going to change much, then small inductors on metal5 etc. may fit in the gaps between the redistribution metal, with enough clearance to be usable.
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