Bit patterned media (BPM) is one of the promising technologies for ultra-high density storage in future hard disk drives.
However, there are many challenges in fabricating BPM. In particular, applications with area density much greater than
1 Tbit/in<sup>2</sup> require magnetic bits to be at sub-10 nm dimensions. Etching at these scales is difficult to achieve with
conventional ion milling techniques. Instead, reactive ion etching (RIE) techniques must be developed to meet the
challenge. In this work, research is presented on the development of a methanol based RIE scheme for fabricating BPM
at ultra-high area densities. The paper will discuss the ability of methanol RIE to etch magnetic and nonmagnetic films
in both the parallel plate and inductively coupled plasma (ICP) RIE configurations, as well as the advantages of both
configurations over Ar ion milling, including enhanced selectivity, minimal redeposition, and less etch induced damage
or erosion. We demonstrate the ability to etch sub-20 nm features in commercially available CoCrPt based perpendicular
recording media and NiFe with selectivity greater than 10:1 relative to mask materials, such as Ta, TaN<sub>x</sub>, Ti, and SiN<sub>x</sub>.
These results, the promises of such a technique, and the feasibility of sub-10 nm scale etching are discussed in detail.
An experimental test bed for investigating the hybrid recording process and that allows for the precise visual alignment of the optical spot and magnetic head is described. Using this spin stand experiments have been performed on three types of hybrid recording where the critical bit dimensions are determined by using either, or both, the thermal and magnetic field profiles. By changing the relative alignment of the optical spot and magnetic head in the down track position four distinct types of marks unique to the hybrid recording process are observed.