With stacked memory, heat is not as much of an issue, since individual memory locations are accessed only occasionally. But for other types of chips, like processors, the ALUs, for instance, are constantly running making for hot spots that need to be cooled if they are inside the stack.
One big advantage of BeSang's approach is that its 3-D layers are very thin--less than 0.5 microns--which allows them to use high-density conventional vias, compared to die stacking which requires lower density through-silicon vias.
Regarding whether it will work, SK Hynix has been evaluating BeSang's technology for quite some time, so they--at least--have confidence it will work.
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