Authors: M.T. Moneck, W. Lin, S. Powell, T. Okada, J. Fujimori, T. Kasuya, M. Katsumura, T. Iida, K. Kuriyama, J. Bain, J.-G. Zhu
Affilation: Carnegie Mellon University, United States
Pages: 230 - 233
Keywords: bit patterned media, electron beam lithography, ion milling
Bit patterned media (BPM) is a promising technology for magnetic recording at ultra-high areal densities beyond 1 Tbit/in2. To be viable, bit patterns must be reliably fabricated across 2.5” disks with few defects and sigma of only 5-10%. This task will likely be achieved with nanoimprint lithography and direct media etching using templates generated by electron beam mastering tools. In this work, we experimentally demonstrate the merits of rotary stage electron beam mastering and the effects of direct pattern transfer on BPM arrays patterned into 2.5” disks at a density of 366 Gbit/in2. Fully circumferential hexagonal BPM arrays and integrated servo were patterned with 42nm down track pitch and 42-84nm cross-track pitch using an EBR-401 rotary stage electron beam tool developed by Pioneer Corporation. The lithographic patterns were transferred into the media through a series of liftoff, reactive ion etching, and ion milling processes utilizing a novel Al protective layer and robust, highly selective C/SiN etch masks designed to generate a high fidelity disk. The pattern quality is demonstrated via contact recording by scanning a recording head in contact with the disk. Analysis clearly shows the 42nm bit pattern can written and read back with good pattern fidelity.
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