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Siloxane Copolymers for Nanoimprint Lithography
Author(s) -
Choi P.,
Fu P.F.,
Guo L. J.
Publication year - 2007
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200600257
Subject(s) - materials science , siloxane , copolymer , resist , polystyrene , nanoimprint lithography , polymer , surface energy , methyl methacrylate , thermoplastic , composite material , silsesquioxane , polymer chemistry , layer (electronics) , medicine , alternative medicine , pathology , fabrication
Presented here is the novel use of thermoplastic siloxane copolymers as nanoimprint lithography (NIL) resists for 60 nm features. Two of the most critical steps of NIL are mold release and pattern transfer through dry etching. These require that the NIL resist have low surface energy and excellent dry‐etching resistance. Homopolymers traditionally used in NIL, such as polystyrene (PS) or poly(methyl methacrylate) (PMMA), generally cannot satisfy all these requirements as they exhibit polymer fracture and delamination during mold release and have poor etch resistance. A number of siloxane copolymers have been investigated for use as NIL resists, including poly(dimethylsiloxane)‐ block ‐polystyrene (PDMS‐ b ‐PS), poly(dimethylsiloxane)‐ graft ‐poly(methyl acrylate)‐ co ‐poly(isobornyl acrylate) (PDMS‐ g ‐PMA‐ co ‐PIA), and PDMS‐ g ‐PMMA. The presence of PDMS imparts the materials with many properties that are favorable for NIL, including low surface energy for easy mold release and high silicon content for chemical‐etch resistance—in particular, extremely low etch rates (comparable to PDMS) in oxygen plasma, to which organic polymers are quite susceptible. These properties give improved NIL results.