Does the technology involve some kind of microscopic heat pipes as well? I always thought stacking the stuff on top of each other would lead to critical problems with heat. Even low-power processors, like those in smartphones, generate more heat than the device can handle, which is indeed a problem with phones. Really low-power stuff in special devices doesn't even need that much processing power or memory to begin with, so I imagine they can be made with any technology no problem.

@Kaarme A modern processor has many sections and components in it's design. It's possible to identify witch produces more heat and place them on the top layer so they can be cooled efficiently. Generally speaking I think I/O produces less heat and can be stacked under the work house of the silicon.

Hasn't Texas Instruments done this since the Cortex-A8 days? Sure, maybe it didn't pack in as many features, but I thought some of the earlier OMAP CPUs were stacked.

schmidtbag:

Hasn't Texas Instruments done this since the Cortex-A8 days? Sure, maybe it didn't pack in as many features, but I thought some of the earlier OMAP CPUs were stacked.

Yes they call the 3d IC tech "PowerStack" which they started shipping IC's made with PowerStack in 2011.

https://imgs3.star.com.tr/imgsdisk//maintmps/2019/04/24/240420191136150933688_2-41.jpg