Diffraction-limited soft x-ray projection lithography with a laser plasma source

Abstract

A laser plasma source of extreme ultraviolet and soft x-ray radiation has been used to print diffraction-limited features using soft x-ray projection lithography. A spherical condenser optic, a Si/Ge transmissive mask and a Mo/Si multilayer-coated Schwarzschild objective having 20:1 reduction ratio were employed to pattern selected single-layer and trilevel resists. At a numerical aperture of 0.12, a 0.1-μm line and space pattern is clearly delineated and weak modulation is observed for the analogous 0.05-μm pattern.