Polymethyl methacrylate/hydrogen silsesquioxane bilayer resist electron beam lithography process for etching 25 nm wide magnetic wires

Abstract

A method of patterning magnetic metallic thin films is presented using a bilayer polymethyl methacrylate and hydrogen silsesquioxane electron beam lithography resist mask combined with ion beam etching. The bilayer resist process allows for the combination of a high-resolution resist mask with easy postprocess removal of the mask without damage to the magnetic quality of the film. Co60Fe20B20 and Co/Ni multilayer films were patterned with electron beam lithography at 10–125 keV down to 25 nm wide features with 2 nm average root-mean square edge roughness. Both the in-plane and out-of-plane magnetic anisotropies of the respective film types were preserved after patterning.