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 ballup 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.

Bit-Patterned Magnetic Recording: Theory, Media Fabrication, and Recording Performance

“…A potential way to solve the problems associated with the patterned topography of BPM is to planarize the BPM disk surface [99]- [101]. This may be accomplished by depositing an appropriate material to fill the grooves between the patterned bits, and then removing the excess fill material on the islands so that the final disk surface has a roughness comparable to conventional continuous media.…”

The Head-Disk Interface Roadmap to an Areal Density of Tbit/in2

“…Residual topography left behind by the BPM manufacturing process challenges air bearing designers to design a slider that can better follow residual topography [34,64,65] as well as media manufacturers to have a uniform overcoat and lubricant coverage of the media surface. Moreover, the residual media topography could lead to excessive induced lubricant roughness on the microscale (lubricant moguls and ripples) unless a new lubricant can be designed.…”

Exploring Strategies to Contact 3D Nano-Pillars

“…Although this type of device can involve many advantages in terms of area and performance (e.g., lower short channel effects), a more challenging manufacturing process is required, especially regarding procedures that create device contacts. Chemical mechanical polishing (CMP) [5] is the better-established method to planarize horizontal structures and then properly contact the devices. However, CMP is not fully adapted to 3D structures [6] and it becomes a drawback in some applications where the overall procedure must remain as simple as possible.…”