- Yellen, B.B. and Friedman, G. and Barbee, K.A., Programmable self-aligning ferrofluid masks for lithographic applications,
IEEE Transactions on Magnetics, vol. 40 no. 4 II
pp. 2994 - 2996 [TMAG.2004.829836] .
(last updated on 2007/04/06)
A novel self-aligned "soft masking" method that is compatible with traditional photolithographic processes is demonstrated. This method uses a suspension of ultra-fine iron oxide grains (ferrofluid) to protect or de-protect selected areas of a magnetically patterned substrate according to a programmable sequence. Automatic mask formation and registration is controlled by ferromagnetic alignment marks patterned on a substrate. External magnetic fields applied to the system causes ferrofluid to aggregate only over designated areas on the surface, thereby masking those areas from UV and/or chemical exposure.
Ferromagnetic materials;Photoresists;Magnetism;Self assembly;Magnets;Magnetization;Magnetic fields;Diffusion;Surface chemistry;Scanning electron microscopy;