Exploration of the Direct Use of Anodized Alumina as a Mold for Nanoimprint Lithography to Fabricate Magnetic Nanostructure over Large Area
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 cm2area with two different pore diameters of163±24 nm and73±7 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 SiO2layer. 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 of172±25 nm by using the mold with a pore diameter of163±24 nm. Finally, we have achieved (001) oriented L10FePt patterned structure with a dot diameter of42±4 nm by using a AAO mold with a pore diameter of73±7 nm. The perpendicularHcof 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.