%0 Journal Article
%T Exploration of the Direct Use of Anodized Alumina as a Mold for Nanoimprint Lithography to Fabricate Magnetic Nanostructure over Large Area
%A M. Tofizur Rahman
%A Hao Wang
%A Jian-Ping Wang
%J Journal of Nanotechnology
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/961630
%X We have explored the direct use of anodized alumina (AAO) fabricated on an Si wafer as a mold for the nanoimprint lithography (NIL). The AAO mold has been fabricated over more than 10£¿cm2 area with two different pore diameters of £¿nm and £¿nm. One of the key challenges of the lack of bonding between the antisticking self-assembled monolayer (SAM) and the AAO has been overcome by modifying the surface chemistry of the fabricated AAO mold by coating it with thin SiO2 layer. Then we have applied the commonly used silane-based self-assembled monolayer (SAM) on these SiO2-coated AAO molds and achieved successful imprinting of resist pillars with feature size of £¿nm by using the mold with a pore diameter of £¿nm. Finally, we have achieved (001) oriented L10 FePt patterned structure with a dot diameter of £¿nm by using a AAO mold with a pore diameter of £¿nm. The perpendicular Hc of the unpatterned and patterned FePt is about 3.3£¿kOe and 12£¿kOe, respectively. These results indicate that AAO mold can potentially be used in NIL for fabricating patterned nanostructures over large area. 1. Introduction Nanoimprint lithography (NIL) has attracted enormous attentions [1¨C6] of the nanofabrication community since its innovation in 1995 [7] and regarded as a next generation nanofabrication tool for fabricating sub-10£¿nm features [3¨C5]. The NIL is a high-throughput and low-cost lithographic technique that showed its potential in many emerging fields, such as electronics [8], photonics [9], bit-patterned media [10, 11], and biological applications [12]. Bit patterned media is of particular interest due its potential in increasing the areal densities in magnetic data storage devices [13, 14]. The mold (also known as template or stamp) is the crucial part of the NIL that determines the throughput and resolution of the later in practical applications. Usually electron beam lithography or focused ion beam lithography followed by the pattern transfer using reactive ion etching (RIE) are used for making the mold. The high cost and low throughput of these methods limit the usefulness of the NIL for fabricating nanopatterns over large area for both of the research and practical applications. Therefore, exploring the fabrication of low-cost and highly robust large-area mold is a must to enjoy the full potential of the NIL. However, to date, only very few works have been reported in this highly demanding area. Park et al. [15] fabricated the large-area mold by using block-copolymer lithography that involved an extra-pattern transfer step. Kim et al. [2] and Lee et al. [16] used AAO
%U http://www.hindawi.com/journals/jnt/2011/961630/