Not really, no. Pretty much all LSI chips (and even a lot of power / analog stuff these days) is flip chip, i.e. mounted metal-layer down (if you see a BGA or w

Not really, no. Pretty much all LSI chips (and even a lot of power / analog stuff these days) is flip chip, i.e. mounted metal-layer down (if you see a BGA or waferscale package, all of these are flip-chip). So the stackup looks like this (roughly to scale): Heatspreader TIM Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Silicon Active layer Metal layers Metal layers Passivation Solder bumps and glue Solder bumps and glue Solder bumps and glue Solder bumps and glue Substrate/interposer/PCB What this article proposes is to put metal layers on BOTH sides of the active layer, so you get more metal closer to it. That's what they mean by "powered from below". If you look at a chip today, they're all "powered from below" in the sense that the metal layers are "below" the active layer and power (and all signals) are fed in from "below" through the interposer.