It’s not 7nm in any feature size it’s seceral times that. It’s achievable usually with multiple patterning and submersion 193nm wavelength in vacuum which goes

It’s not 7nm in any feature size it’s seceral times that. It’s achievable usually with multiple patterning and submersion 193nm wavelength in vacuum which goes to about 145 in water and they likely are using something other than water and you also have temperature which affects the refractive index.