Fabrication of Planarized Discrete Track Media Using Gas Cluster Ion Beams

We studied the effect of the duty ratio, i.e., the ratio of hill width to pitch, of patterned diamondlike carbon (DLC) surfaces on Ar gas cluster ion beam (GCIB) planarization effect. The patterns of 40 nm depth were fabricated on Si substrates by electron beam lithography and CHF 3 reactive-ion etching. The pitch of the line-and-space pattern was 300 nm and three duty ratios were adopted. Then, refilling materials were deposited to 50 nm thickness on the patterned substrates. The test samples were irradiated by Ar-GCIB and the resultant surface profiles were measured by atomic force microscopy. The acceleration energy for one cluster was 20 keV. The dose was set in the range from 5Â10 14 to 5Â10 16 ion/cm 2 . Although there was a difference in the dose, the patterns clearly disappeared upon irradiating GCIB. The reduction rate of the peak-to-valley height decreased as the width of the hill increased. We indicated that GCIB irradiation is effective for the planarization of patterned surfaces with various duty ratios.

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“…Furthermore, N 2 GCIB is a candidate finishing process because it can planarize the surface roughness with small wavelength. 14…”

Section: Resultsmentioning

confidence: 99%

Effect of duty ratio of patterned surface on planarization by gas cluster ion beams

Nagato

Toyoda

Naito

et al. 2011

Journal of Applied Physics

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“…In this case, no effort was made to improve the roughness by applying, for instance, a planarizing film and sequential angled IBE under a large angle. 78,79 The difficulty in implementing such planarization steps would be to find a polymer coating that is not too thick but shows a good step-coverage. Additionally, tn the cited works, Ra roughness values of a few nanometers were reduced to several angstroms, however, considering significant etch depths of 300 nm.…”

Section: Au Hollow Nanopillars Composition and Morphologymentioning

confidence: 99%

A wafer-scale fabrication method for three-dimensional plasmonic hollow nanopillars

et al. 2021

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“…A potential way to solve the problems associated with the patterned topography of BPM is to planarize the BPM disk surface [99]- [101]. This may be accomplished by depositing an appropriate material to fill the grooves between the patterned bits, and then removing the excess fill material on the islands so that the final disk surface has a roughness comparable to conventional continuous media.…”

Section: A Head-disk Interfacementioning

confidence: 99%

Bit-Patterned Magnetic Recording: Theory, Media Fabrication, and Recording Performance

et al. 2015

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Bit Patterned Media (BPM) for magnetic recording provides a route to thermally stable data recording at >1 Tb/in 2 and circumvents many of the challenges associated with extending conventional granular media technology. Instead of recording a bit on an ensemble of random grains, BPM is comprised of a well ordered array of lithographically patterned isolated magnetic islands, each of which stores one bit. Fabrication of BPM is viewed as the greatest challenge for its commercialization. In this article we describe a BPM fabrication method which combines rotary-stage e-beam lithography, directed self-assembly of block copolymers, self-aligned double patterning, nanoimprint lithography, and ion milling to generate BPM based on CoCrPt alloy materials at densities up to 1.6 Td/in 2 (teradot/inch 2 ). This combination of novel fabrication technologies achieves feature sizes of <10 nm, which is significantly smaller than what conventional nanofabrication methods used in semiconductor manufacturing can achieve. In contrast to earlier work which used hexagonal closepacked arrays of round islands, our latest approach creates BPM with rectangular bitcells, which are advantageous for integration of BPM with existing hard disk drive technology. The advantages of rectangular bits are analyzed from a theoretical and modeling point of view, and system integration requirements such as provision of servo patterns, implementation of write synchronization, and providing for a stable head-disk interface are addressed in the context of experimental results. Optimization of magnetic alloy materials for thermal stability, writeability, and tight switching field distribution is discussed, and a new method for growing BPM islands from a specially patterned underlayer -referred to as "templated growth" -is presented. New recording results at 1.6 Td/in 2 (roughly equivalent to 1.3 Tb/in 2 ) demonstrate a raw error rate <10 -2 , which is consistent with the recording system requirements of modern hard drives. Extendibility of BPM to higher densities, and its eventual combination with energy assisted recording are explored.Index Terms-Bit patterned media, hard disk drive, block copolymer, self-assembly, double patterning, e-beam lithography, sequential infiltration synthesis, nanoimprint lithography, templated growth, thermal annealing, Co alloys, magnetic multilayers, interface anisotropy, magnetic recording, write synchronization, prepatterned servo, areal density.

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Fabrication of Planarized Discrete Track Media Using Gas Cluster Ion Beams

Cited by 21 publications

References 8 publications

Effect of duty ratio of patterned surface on planarization by gas cluster ion beams

Effect of duty ratio of patterned surface on planarization by gas cluster ion beams

A wafer-scale fabrication method for three-dimensional plasmonic hollow nanopillars

Bit-Patterned Magnetic Recording: Theory, Media Fabrication, and Recording Performance

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