Proceedings Article | 25 September 2010
Proc. SPIE. 7823, Photomask Technology 2010
KEYWORDS: Etching, Argon, Ions, Chemistry, Magnetism, Photomasks, Reactive ion etching, Tantalum, Beam propagation method, Plasma
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.
