Fabrication of 5–7 nm wide etched lines in silicon using 100 keV electron‐beam lithography and polymethylmethacrylate resist

The present limit of around 10 nm for the width of lines fabricated by e‐beam lithography using polymethylmethacrylate (PMMA) resist on silicon substrates has been overcome. 5–7 nm wide etched lines in bulk Si substrates have been produced. A 65 nm thick layer of PMMA was exposed with an 80 kV electron beam of diameter smaller than 5 nm. After exposure the resist was developed in 3:7 cellosolve:methanol with ultrasonic agitation. The pattern in resist was transferred to the Si substrate with reactive ion etching. Lines of width varying between 5 and 7 nm were recorded using an S‐900 scanning electron microscope which has a resolution of 0.7 nm.