Fabrication of templates for achieving one-to-one grain matching in HAMR media

In previous work, we reported on the fabrication of a regular template for the controlled two-phase growth of conventional CoPt-SiO₂ PMR media. The template consisted of dome-morphology patterned into a Platinum FCC (111) textured thin film. When CoPt-SiO₂ was sputtered, the artificially patterned domes acted as sites on which the CoPt grains grew, with the segregant growing within the trenches between these domes[1]. In current PMR media, a similar approach is used to achieve grain-to-grain matching between the Ru underlayer and the CoPt grains, wherein the Ru dome morphology is fabricated using high Ar pressure during the sputtering process. In case of HAMR media however, achieving grain-to-grain matching between the underlayer is proving quite challenging. In this work, we explore using a pre-fabricated dome morphology in the underlayer to achieve grain-to-grain matching for the HAMR media (FePt). Block copolymers are first used to fabricate a pattern consisting of a hexagonal lattice of spheres of one block in the other block´s matrix . The pattern is then transferred into an amorphous carbon hard mask using Reactive Ion Etching (RIE) and subsequently into the underlayers using ion-milling, as described in our previous work[1] .