Magnetic printing technology - application to HDD

As the recording density of hard disk drives is being rapidly increased, the current servo track writing method using a conventional servo track writer has become more costly and technically difficult. In order to solve the problem, the authors propose a new magnetic contact duplication technology using a lithographically patterned master disk and discuss the printing process reliability for practical implementation to the product drives, in particular, from the viewpoint of master-slave contact issues. The air channel structure provided on the master disk surface allows close surface contact between the master and the slave disks, yielding very small amplitude modulation of the printed signal. The master disk was found durable over 1 million printing shots without giving any serious damage to the lithographically patterned ferromagnetic film. Moreover, organic and inorganic contamination tests show that the contact printing operation does not increase contamination on the printed disks. The magnetic printing technique can also be successfully applied to perpendicular recording media using the same master disk as for longitudinal media.