Directed Self-Assembly of Block Copolymer for Bit Patterned Media with Areal Density of 1.5 Teradot/Inch² and Beyond

Figure 9

(a) Schematic representation of fabricating a pillar-tone dots-array template based on a hole-tone template. (A) Evaporate a thin Cr layer onto a fabricated hole-tone dots-array template, (B) high-angle argon ion milling process to remove the top Cr layer only, (C) fused silica etch using CF₄ RIE, and (D) strip Cr residues left after CF₄ RIE. (b) Large-scale SEM image of a pillar-tone dots-array template at 1.0 Td/in². (c) Cross-sectional and tilted SEM images showing the pillar height of about 25 nm. (d) Tilted SEM image of a patterned nanoscale “Seagate” logo at a density of 1.0 Td/in².