They’re already running a plant in Arizona, and I heard it’s going really well. It won’t matter.
https://www.techpowerup.com/331104/tsmc-granted-government-p...
https://www.reuters.com/technology/tsmc-begins-producing-4-n...
So a blanket tariff would definitely apply even to the production of that plant. Which is why lots of CEO's (including Tim Cook) are trying to suck-up to Trump right now, to get an exception made for their imports.