craigjb

For chips with integrated CPU+GPU+NPU, it could be worth it tech-wise. The GPU and NPU can eat HBM bandwidth. For general purpose CPU code, the HBM would likely not be worth it. It's high bandwidth, but you trade latency, and general CPU code is branchy. Economics-wise, the HBM stacks alone will cost more than a consumer CPU (or APU).

[edit] The packaging needed to support HBM is also much more expensive too. If demand for current HBM applications tanks and the manufacturing lines need filled, then maybe. Currently, the price point would make it very very niche.

HBM4 has over 2048 signals to the processor’s PHY with tight signal integrity requirements that require the HBM stack to be < 0.5 mm from the processor die. That’s why HBM integration is done with interposers (soldered on the package). So, it’d be the CPU package that integrates it. Motherboard is too far away.

Apple has not shipped an InFO-PoP with side-by-side integrated die yet. This is expected to be the first one, using RDLs for the die-to-die interconnect (so different than M-Ultra series that uses silicon bridges).

Applied Materials, Lam Research, and KLA are all U.S. companies. ASML supplies lithography, but hundreds of other tools come from these companies.

The terms to search for are fan-out wafer level packaging (FOWLP) and TSMC InFO. The chiplets come from different wafers and are reconstituted into a molded plastic wafer, allowing multiple die side-by-side. Then multiple layers of wires are built on top, terminating in a BGA.