NotFuzzyWarm,
I have no experience in designing chips, but for me it is very very interesting theoretical price of bitcoin ASIC.
I think for many bitcointalkers too.
Numbers from your article are saying nothing.
how many transistors are in this 28nm planar device or in 7nm soc ?
I can provide you info about russian quasi-CPU, each develop cost was +- 25mln usd.
baikal-m 28nm
die size 350mm2
transistors 3.5bln
elbrus-8c 28nm
die size 240mm2
transistors 2bln
so we have develop cost
71-104thousand usd per 1mm2 or per +-10mln transistors
hundreds thousands dollars, not hundreds millions.
it's 28nm technology, 5nm is more expensive.
***
Of course chip should be tested.
Fabs has special service called "shuttle". You can provide them design as low as 1mm2 and they will create chip for testing purposes.
https://europractice-ic.com/schedules-prices-2021/GF 12nm 26000eur/1mm2
TSMC 28nm 9000eur/1mm2
Once again, we speak about thousands, but not millions dollars.
I can't find prices for 5nm shuttle. But I feel it will be in 100000eur/1mm2 region.
***
sha-256 core is very simple in design.
one-round need about 20k NAND gates or 80k transistors.
bitcoin uses two-round sha-256 = 160k transistors.
5nm has about 160mln transistors per 1mm2.
So for 1mm2 5nm design we just need to copy-paste 2000 sha-256 cores and design special control unit to synchronize theirs work.
It's really not hundreds millions dollars for such design.
That's all ! We don't need gigantic design such as 15mm*20mm. Such design of course can cost hundreds millions of dollars.