70 nm features on 140 nm period using Evanescent Near Field Optical Lithography

We have investigated the resolution limits for Evanescent Near Field Optical Lithography (ENFOL) both experimentally and computationally. Feature sizes as small as 70 nm on a 140 nm period have been achieved using broadband illumination (365-600 nm). This resolution is well below the diffraction limit associated with projection lithography. Line widths down to 50 nm have been achieved for larger period gratings. Simulations of the exposure process show that feature sizes smaller than lambda/20 can be resolved using this technique.