With existing materials, further reductions in the grain volume would result in data loss occurring spontaneously due to superparamagnetism.
[4] Patterned media is predicted to enable areal densities up to 20–300 Tbit/in2 (3.1–46.5 Tbit/cm2) as opposed to the 1 Tbit/in2 (160 Gbit/cm2) limit that exists with current HDD technology.
This process is different in bit patterned media recording where data should be written on tracks with predetermined shapes, which are created by lithography (see below) on the disk.
Patterned media recording has some specific challenges in terms of servo control design:[6] In preliminary research, one of the processes investigated for creating prototypes was ion beam proximity lithography.
To create sufficient substrates is to maintain size uniformity of the openings which is transferred to the mask during the fabrication process (etching).
Many factors contribute to the achievement and maintenance of size uniformity in the mask, such as: pressure, temperature, energy (amount of voltage), and power used when etching.