Nanosphere Lithography of Co/Pd Multilayer Film for Advanced Media

We reported for the first time nanosphere lithography (NSL) of perpendicular anisotropy Co/Pd multilayer film for advanced media application. NSL is an inexpensive patterning technique that includes the formation of a monolayer of polystyrene spheres, shrinking of the nanospheres, and then ion milling of the film into nanopillars with reduced nanospheres acting as a mask. Polystyrene nanospheres were shrunk under different conditions of oxygen plasma ashing. Field emission scanning electronic microscopy (FESEM) and X-ray diffraction (XRD) were employed to observe the morphology and the crystal structure respectively of magnetic nanocolumn arrays. Alternating gradient magnetometer (AGM) was used to characterize the magnetic properties, such as Mst, Mrt and squareness of patterned films and correlated structural properties. We have developed a hard mask technique compared with NSLto further decrease the nanopillar size to ~10nm for improved recording density.