Large Area Ferromagnetic Nanostructures Fabricated with Sequential NanoImprint Lithography
Li Tan
Collaborators Jeff Shield, David Sellmyer
This seed project will investigate (A) the use of Sequential NanoImprint Lithography (SNIL) to fabricate a high resolution master stamp and (B) transferring topographic features from this stamp to SiO2 and finally, through deposition of a magnetic film on SiO2, to obtain ferromagnetic nanostructures with an ultra-high density (of order 1012/in2) over a 2.5-inch diameter area.
The strategy of SNIL in miniaturization and nanostructure formation is shown in Fig. 1, where a balloon analogy with the words of “Seed Grant” is shown on the left to assist the interpretation. Within this SNIL process, synthetic polymer under large elastic deformation is used as substrate and the softness/flexibility of polymer is harnessed to regulate pattern dimension and density (Step 1-5, Fig. 1). In comparison with other forms of soft and nanoimprint lithography, where lack of tunability on pattern dimension and density has caused extreme difficulties to reach a resolution beyond e-beam lithography, SNIL has flexibility on tuning both bit and pitch dimensions and thus, a much higher potential to reach nanometer precision.
After the final step of SNIL, miniaturized stamps can be used to create topography features to surfaces of SiO2. Subsequent sputtering of a Co/Pt multilayer leads to formation of patterned magnetic media.
Fig. 1. The Sequential NanoImprint Lithography (SNIL) technique and fabrication yield.