Design of Ni Mold for Discrete Track Media

Nano imprint lithography (NIL) and NIL mold formation play a vital role in discrete track media (DTM) production. In this paper, we created a nickel (Ni) mold for DTM production using an R-theta electron beam mastering device to draw data groove and servo information on a silicon substrate master, and transferred the resulting pattern to a nickel mold via an electroplating process. The resulting Ni mold exhibits a 90-nm track pitch (282 kTPI equivalent), 30-nm line width, 60-nm groove width, 60-nm land height, and 7-nm line width roughness (LWR). Since variations in downtrack LWR and line edge roughness (LER) on the Ni mold are much smaller than variations in the size of HDD media magnetic clusters, we believe the Ni mold production method that is the subject of this study can be successfully applied to the production of DTM molds for next-generation HDD media.