Fabrication of chevron patterns for patterned media with block copolymer directed assembly

Liu, Guoliang; Nealey, Paul F.; Ruiz, Ricardo; Dobisz, Elizabeth A.; Patel, Kanaiyalal C.; Albrecht, T. R.

doi:10.1116/1.3650697

Cited by 14 publications

(7 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If particularly complex servo patterns are required, BCPs cannot form the necessary patterns, and servo patterns have to be integrated by applying an additional lithographic step without DSA. However, we have proposed two relatively simple types of servo patterns ; offset burst 43 and chevron 44 patterns ; which can be generated by BCPs to encode the position information needed for track following. Offset burst patterns are a series of sections of circumferential lines that shift a fraction of a track along the cross track direction.…”

Section: Resultsmentioning

confidence: 99%

The Limits of Lamellae-Forming PS-b-PMMA Block Copolymers for Lithography

et al. 2015

Self Cite

View full text Add to dashboard Cite

We explore the lithographic limits of lamellae-forming PS-b-PMMA block copolymers by performing directed self-assembly and pattern transfer on a range of PS-b-PMMA materials having a full pitch from 27 to 18.5 nm. While directed self-assembly on chemical contrast patterns was successful with all the materials used in this study, clean removal of PMMA domains and subsequent pattern transfer could only be sustained down to 22 nm full pitch. We attribute this limitation to the width of the interface, which may represent more than half of the domain width for materials with a critical dimension below 10 nm. With the limit of pattern transfer for PS-b-PMMA set at ∼11 nm, we propose an integration scheme suitable for bit patterned media for densities above 1.6 Tdot/in(2), which require features below this limit. Directed self-assembly was carried out on chemical contrast patterns made by a rotary e-beam lithography system, and pattern transfer was carried out to demonstrate fabrication of large area (up to 25 mm-wide annular band of circular tracks) nanoimprint templates for bit patterned media. We also demonstrate compatibility with hard disk drive architecture by fabricating patterns with skewed radial lines with constant angular pitch and with servo patterns that are needed in hard disk drives to generate a radial positional error signal (PES).

show abstract

Section: Resultsmentioning

confidence: 99%

The Limits of Lamellae-Forming PS-b-PMMA Block Copolymers for Lithography

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…In addition, the ability to synthesize homogenous or combinatorial arrays of nanoparticles on surfaces with control over individual particle composition and size will enable important fundamental studies and technological applications in fields spanning catalysis, nanomagnetism, microelectronics, and plasmonics. Finally, the pathway-dependent observations pertaining to these polymer nanoreactors likely will extend to other block copolymer-mediated particle syntheses, including ones that target 2D-and 3D-latticed structures (30)(31)(32).…”

Section: Resultsmentioning

confidence: 99%

Delineating the pathways for the site-directed synthesis of individual nanoparticles on surfaces

Liu

Eichelsdoerfer²,

Rasin

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

111

View full text Add to dashboard Cite

Although nanoparticles with exquisite properties have been synthesized for a variety of applications, their incorporation into functional devices is challenging owing to the difficulty in positioning them at specified sites on surfaces. In contrast with the conventional synthesis-then-assembly paradigm, scanning probe block copolymer lithography can pattern precursor materials embedded in a polymer matrix and synthesize desired nanoparticles on site, offering great promise for incorporating nanoparticles into devices. This technique, however, is extremely limited from a materials standpoint. To develop a materials-general method for synthesizing nanoparticles on surfaces for broader applications, a mechanistic understanding of polymer-mediated nanoparticle formation is crucial. Here, we design a four-step synthetic process that enables independent study of the two most critical steps for synthesizing single nanoparticles on surfaces: phase separation of precursors and particle formation. Using this process, we elucidate the importance of the polymer matrix in the diffusion of metal precursors to form a single nanoparticle and the three pathways that the precursors undergo to form nanoparticles. Based on this mechanistic understanding, the synthetic process is generalized to create metal (Au, Ag, Pt, and Pd), metal oxide (Fe 2 O 3 , Co 2 O 3 , NiO, and CuO), and alloy (AuAg) nanoparticles. This mechanistic understanding and resulting process represent a major advance in scanning probe lithography as a tool to generate patterns of tailored nanoparticles for integration with solid-state devices.T he integration of nanoparticles into devices has enabled applications spanning sensing (1, 2), catalysis (3), electronics (2), photonics (4), and plasmonics (5, 6), but synthesizing individual nanoparticles with control over size, composition, and placement on substrates is challenging (1-3, 6, 7). With conventional approaches, nanoparticles are synthesized and subsequently positioned on a surface using techniques such as parallel printing (8), surface dewetting (9, 10), microdroplet molding (7), nanoparticle sliding (11), direct writing (4, 12, 13), and self-assembly (2, 14, 15). However, it is difficult and in most cases, impossible to use these methods to reliably make and position a single particle on a surface with nanometer-scale control.In contrast with the conventional synthesis-then-positioning paradigm, which is the basis for most single-particle device incorporation schemes, scanning probe block copolymer lithography (SPBCL) is an example of precursor positioning-then-synthesis. The technique uses concepts from the block copolymer community (16) and the positional control offered by dip-pen nanolithography (DPN) (17) to deliver attoliter volumes of a metalcoordinated block copolymer onto a surface, which then can be used to synthesize individual nanoparticles (18,19). Importantly, SPBCL allows one to directly synthesize arbitrary patterns of single nanoparticles over large areas on a surface, which has been usef...

show abstract

“…Therefore, forming arbitrary non-regular patterns, such as servo patterns, is challenging for BCP lithography. However, two types of servo structures, offset field and chevron, were proposed, which can be generated by BCPs along with circumferential lines to encode the position error signal (PES) for track following [75]. Offset patterns are a series of sections of circumferential lines that shift along the cross-track direction.…”

Section: ) Design Requirements For Self-assembled Patternsmentioning

confidence: 99%

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

et al. 2015

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Fabrication of chevron patterns for patterned media with block copolymer directed assembly

Cited by 14 publications

References 31 publications

The Limits of Lamellae-Forming PS-b-PMMA Block Copolymers for Lithography

The Limits of Lamellae-Forming PS-b-PMMA Block Copolymers for Lithography

Delineating the pathways for the site-directed synthesis of individual nanoparticles on surfaces

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

Contact Info

Product

Resources

About