We are not concentrating light below the diffraction limit, instead we are printing features below the diffraction limit with multiple exposures. See here: htt

We are not concentrating light below the diffraction limit, instead we are printing features below the diffraction limit with multiple exposures. See here: https://en.m.wikipedia.org/wiki/Multiple_patterning https://en.m.wikipedia.org/wiki/Multiple_patterning Edit: the exponential rise happens because to go 2x smaller I now need to double my # of masks. Of course, in practice overlay accuracy could kill you first.