Electron-beam lithography of Co∕Pd multilayer with hydrogen silsesquioxane and amorphous Si intermediate layer

Abstract

We propose a patterning method to form nanostructures of a Co∕Pd multilayer by using electron-beam lithography with an amorphous silicon (a-Si) layer and two-step etching process. On the Co∕Pd multilayer, a-Si is sputter deposited and hydrogen silsesquioxane (HSQ), the electron-beam resist, is spin coated sequentially. We found that an a-Si intermediate layer between the Co∕Pd underlayer and HSQ overlayer improves adhesion of HSQ on the metallic underlayer after electron-beam dosing and chemical development; it also increases etch selectivity between the Co∕Pd multilayer and its overlayers. We demonstrate that a Co∕Pd multilayer can be patterned successfully as a nanowire array using the suggested process.