New process to fabricate heat assisted magnetic recording media with extremely small grain size

A new process to fabricate FePt granular media for heat assisted magnetic recording, named as Embedded Mask Pattering (EMP) process, was proposed and experimentally demonstrated. In this process, a granular hard mask layer (Ru-SiO₂) was deposited on top of a L1₀ FePt continuous layer. The granular pattern of the mask layer was then transferred down to the FePt layer using a dry etching process. Unlike any conventional media fabrication process, in this new media fabrication process the granular structure of FePt layer is only defined by the mask layer while its magnetic properties are determined by the FePt continuous film. Since achieving good magnetic properties is separated from manipulating the granular structure for this process, the mean grain size and size distribution of FePt HAMR media can be extremely small by optimizing the mask layer and pattering transfer process, while keeping its good magnetic performances. This process is potentially compatible to today´s disk media production line.