TSMC is building a lot of new 28nm production with plans to shut down all their older nodes and move everyone over in the next few years.
GlobalFoundries (formerly AMD fabs) created a brand-new 22nm planar process specifically for older chips as an upgrade to other company's 28nm processes.
Profits seem possible if you approach it the right way.
We're talking about different things here. I was talking about building new fabs for 28nm nodes and you're talking about TSMC upgrading existing fabs from older nodes to 28nm production.
Of course upgrading an existing older "sunk-cost" fab to 28nm production will be profitable, but not building a new one from scratch just for that same older node.
But now this makes the subsidies angle make more sense: You subsidize initial construction and then the domestic plant remains online indefinitely because the construction is a sunk cost and the incremental cost of upgrades over time is sustainable.
The math works out a lot better when you’re upgrading pre-EUV fabs or expanding an existing facility. A lot of the gear and setup is mostly the same such as wafer cleaning, HVAC and isolation, etc and the local challenges to setup and labor have been figured out.
GlobalFoundries (formerly AMD fabs) created a brand-new 22nm planar process specifically for older chips as an upgrade to other company's 28nm processes.
Profits seem possible if you approach it the right way.