This work was supported by the National Science Foundation (ECS 0424204 and ECS 0508252). The authors thank Dr. Jin-Sung Kim for helping with mold fabrication.
Siloxane Copolymers for Nanoimprint Lithography†
Article first published online: 24 NOV 2006
Copyright © 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Functional Materials
Volume 17, Issue 1, pages 65–70, January, 2007
How to Cite
Choi, P., Fu, P.-F. and Guo, L. J. (2007), Siloxane Copolymers for Nanoimprint Lithography. Adv. Funct. Mater., 17: 65–70. doi: 10.1002/adfm.200600257
- Issue published online: 4 JAN 2007
- Article first published online: 24 NOV 2006
- Manuscript Revised: 22 JUN 2006
- Manuscript Received: 21 MAR 2006
- National Science Foundation. Grant Numbers: ECS 0424204, ECS 0508252
- Block copolymers;
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.