Nanoscale Patterning by UV Nanoimprint Lithography Using an Organometallic Resist

This paper presents the fabrication of poly(ferrocenylmethylphenylsilane) (PFMPS) patterns by step-and-flash imprint lithography for use as high-contrast etch masks in dry etch processes. PFMPS was spin-coated onto a resist template made by UV nanoimprint lithography to create a reactive ion etch resist layer with a thickness variation corresponding to the imprinted pattern. Etching back the excess of PFMPS by argon sputtering revealed the imprinted organic resist material, which was subsequently removed by oxygen plasma. PFMPS lines down to 30 nm were obtained after removal of the organic resist by oxygen plasma. Because PFMPS contains iron and silicon atoms in its main chain, it possesses a high resistance to oxygen reactive ion etching and, e.g. CHF3/O-2 or SF6/O-2 reactive ion etch processes. PFMPS patterns formed after imprinting were subsequently transferred into the underlying silicon substrate, and etch rates of 300 nm/min into Si and around 1 nm/min into the PFMPS layer were achieved, resulting in an etch contrast of approximately 300.