Patterned media such as discrete track media (DTM) or bit patterned media (BPM) have been developed for the next high-density recoding media. On the patterned media, nano-scale patterns are fabricated on magnetic layer in order to separate each bit. However, it is necessary to planarize them so as to maintain the flying stability of a slider. In order to overcome the shortcomings of planarization technique, we have proposed gas cluster ion beam (GCIB) processing. In contrast to atomic or molecular ion beams, GCIB induces lateral motion of surface atoms, which is referred to as “lateral sputtering”. This effect induces strong surface smoothing. In addition, the low energy/atom characteristics of GCIB (energy as low as several eV/atom) help to process without causing heavy damage. In the present study, we fabricated patterned media by nano-imprint lithography and demonstrated surface planarization by using Ar and N₂-GCIB. From the atomic force microscope (AFM) observation, it is found that a GCIB produces excellent planarization of line-and-space patterns refilled with non-magnetic films. Further, it preferentially modifies the surface bumps, which resulted in the minimal thickness loss. In addition, the flyability test of a slider over the DTM planarized with GCIB indicated an almost 10% reduction of instability. Magnetic force microscope (MFM) and Kerr rotation measurements for magnetic property evaluations revealed that GCIB planarization did not produce any change in the magnetic characteristics of DTM. Thus, it was demonstrated that GCIB planarization is effective for fabricating patterned media.

Noriaki Toyoda*, Graduate school of engineerign, University of Hyogo, Japan
Kouki Naito, Graduate school of engineerign, University of Hyogo, Japan
Isao Yamada, Graduate school of engineerign, University of Hyogo, Japan

*presenting author