@User: I didn't see a discussion on packaging. . . Anyway, I am not against doing WLCSP if SkyWater will support it, otherwise we will have to look at the cost of having a 3rd party vendor do the redistribution layer. I can add this, though: Last year I did a bump bond package for the efabless Raven to be used by zGlue, and it was a 6x6 array of bumps at a pitch of 0.5mm, and I managed to make a footprint for it on a cheap 2-layer PCB (that is, no blind vias) which worked quite well.