Magnetic Damage and Performance Recovery in Discrete Track Media

Discrete track media (DTM) has been widely studied recently as a solution to achieve high track density for hard disk drives. In DTM, nano-patterning process is used to isolate magnetic tracks. During the fabrication process, magnetic damage occurs in the resist striping process using O₂ plasma. The on-track SNR of DTM degrades by ~ 2-3 dB. We used Ar IBE cleaning process to remove the oxide layer. The removal process induces unexpected magnetic property change. Nevertheless, this process can still improve the SNR significantly. However, the cleaning step also causes track corner rounding, and results in a faster SNR roll-off at high linear densities. Several methods for further improving DTM performance are discussed in this paper, including using a protective cap layer and media magnetic design reoptimization.