Low-energy electron beam lithography with 30 nm resolution

Electron beam lithography (EBL) with a low accelerating voltage ( approximately 2 kV) was utilized for the fabrication of nanostructures. A resolution of 30 nm was achieved for both sparse and dense lines. The high resolution resulted from the low aberrations of the electron optics system of the field emission scanning electron microscope used as an EBL machine and from the preferred small-angle forward scattering characteristic of the low-energy exposing electrons. By comparison with 50 kV EBL, the authors show a large reduction in the proximity effect and demonstrate a 60 nm spacing between two large exposed areas. Moreover, it is shown that the critical dose at 2 kV is more than an order of magnitude less than that at 50 kV exposures.