Flexible magnetic lithography is a process qualitatively analogous to contact optical lithography which transfers information from a patterned magnetic mask (analog of optical photomask) to magnetic media (analog of photoresist), and is interesting for applications in instantaneous parallel magnetic recording. The magnetic mask consists of patterned soft magnetic material (FeNiCo, FeCo) on a flexible plastic substrate, typically Polyethylene Teraphtalate (PET). When uniformly magnetized media is brought into intimate contact with the magnetic mask, an externally applied magnetic field selectively changes the magnetic orientation in the areas not covered with the soft magnetic material. Flexible substrate of the magnetic mask o.ers superior compliance to magnetic media which is likely to have imperfect flatness and surface particulate contamination.
Although magnetic in physical nature, flexible magnetics draws interesting parallels to flexible electronics, especially in challenges of fabrication of sub-micron patterns on thin flexible plastic substrates. We fabricated samples of sub-micron patterned FeCo and FeNiCo magnetic masks on PET substrates by using combined lamination/release process of PET films. Rigid substrates, typically silicon or quartz were initially laminated with PET films and processed using standard fabrication procedures. After completing magnetic mask device fabrication, PET films were released from the rigid substrates.
We successfully transferred patterns from magnetic masks to hard disk CrPtCo-based magnetic media. The details of the method, including physics of the magnetic lithography pattern transfer, fabrication of the magnetic mask on flexible PET substrates, lamination and release of PET films, and magnetic force microscopy (MFM) images of the magnetic transition patterns are reported.