Possible in principle, very hard in practice, even with full access to necessary asml machines and with a lot of experience and expertise without the difficulty

Possible in principle, very hard in practice, even with full access to necessary asml machines and with a lot of experience and expertise without the difficulty of stealing incomplete information. They certainly can’t “just” do that, no :-). Source: see Intel, who have the money, experience, expertise, time, incentive and asml machines to do this and are making a big bet on gaining TSMC parity (at least). If the stock price is any indication, they are unlikely to succeed. Disclaimer: I work at Intel but in an unrelated area. My information in this area is the same as an interested outsider. I do fiercely want them to succeed in becoming the only tsmc competitor.