Planarization of patterned magnetic recording media to enable head flyability

Abstract

The fabrication and planarization of patterned magnetic recording media is investigated and the flyability of magnetic recording sliders on a patterned and planarized 65 mm glass disk is investigated a small coupon of patterned media with an array of nano pillars of 40 nm diameter and 60 nm height was first fabricated by e-beam lithography and reactive ion etching (RIE) to investigate the planarization process for patterned media. Since read/write flyability tests require a patterned disk rather than a small coupon area, we have prepared a bit patterned glass disks of 65 mm diameter (2.5 in.) using the so-called “Ag ball-up process” in combination with RIE. This “Ag ball-up process” permits the manufacturing of a nano-sized bit patterns on a large area, i.e., on a disk with 65 mm diameter. Planarization of the patterned area was performed with hydrogen silsesquioxane (HSQ) by spin coating. The HSQ layer was back-etched using RIE, resulting in a smooth surface. “Flyability testing” indicates significantly improved flying stability of typical magnetic recording sliders on the planarized glass disks, with the standard deviation of flying height fluctuations on the order of 0.1 nm. The latter value is comparable to that of “smooth” disks.