Very interesting. But why all the foundry doesn't take this route? considering the cost is low and will be very competitive without hinderrance of the scarecity of the EUV lithograpy.
not all foundries have in house packaging, they outsource to a dedicated OSAT (outsourced assembly and test) company. In addition, the capability to develop advanced packaging techniques is
very different than foundry. But yes, more and more companies are moving in this direction. The main thing with foundries is that they need to make their money back. They can't do that if they admit that you can get same results with different packaging. The other part is, you have to design from the ground up for this sort of chip.
That is for outsourced processes ie not proprietary but even there there's plenty of advanced capabilities -
The real heavy hitter is in proprietary packaging techniques such as
YMTC is not the only company to do this btw,
The important part for this sort advanced packaging design is that
not all parts of the chip have to be manufactured on the same process. For example, you can manufacture ONLY the CPU on 7 nm, have memory on 20 nm, and all the I/O circuits on 180 nm, then stack them.
For example, YMTC manufactures
, but they manufacture their
. This means that they can use SMEE's low cost 90 nm DUV for the 180 nm and reserve the 20 nm for the (much higher cost) 28 nm DUV, or outsource their I/O wafers only to lower end fabs.
, what this means is automatic 30% increase in memory density per die and cuts the number of steps in half (you just repeatedly pattern 1 wafer type).
The challenges, of course, are huge. It's an entirely different mentality than monolithic chip.
