I suggest you take a look at how easy maskless photolithography is: https://sam/zeloof.xyz https://sam/zeloof.xyz Theoretically it should be feasible to fab 35

I suggest you take a look at how easy maskless photolithography is: https://sam/zeloof.xyz https://sam/zeloof.xyz Theoretically it should be feasible to fab 350 nm without double-patterning by optimizing a simple immersion DLP/DMD i-line stepper. I think ArF immersion with double-patterning should be able to do maskless 90 nm.