Photopatterning of Block Copolymer Thin Films

Lane, Austin P.; Maher, Michael J.; Willson, C. Grant; Ellison, Christopher J.

doi:10.1021/acsmacrolett.6b00075

Cited by 24 publications

(23 citation statements)

References 107 publications

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“…Alternatively, photo-induced switching of surface wettability may provide similar control via a complementary mechanism. 24,25 sandwiched between a solid substrate and polystyrene top coat. 26 Notably, with their materials, island and hole formation is suppressed in favor of stretched or compressed block copolymer domains that uniformly cover the as-cast thickness with an integral number of periods.…”

Section: Discussionmentioning

confidence: 99%

Structure, Stability, and Reorganization of 0.5 L₀ Topography in Block Copolymer Thin Films

et al. 2016

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The structure, stability, and reorganization of lamella-forming block copolymer thin film surface topography ("islands" and "holes") were studied under boundary conditions driving the formation of 0.5 L thick structures at short thermal annealing times. Self-consistent field theory predicts that the presence of one perfectly neutral surface renders 0.5 L topography thermodynamically stable relative to 1 L thick features, in agreement with previous experimental observations. The calculated through-film structures match cross-sectional scanning electron micrographs, collectively demonstrating the pinning of edge dislocations at the neutral surface. Remarkably, near-neutral surface compositions exhibit 0.5 L topography metastability upon extended thermal treatment, slowly transitioning to 1 L islands or holes as evidenced by optical and atomic force microscopy. Surface restructuring is rationalized by invoking commensurability effects imposed by slightly preferential surfaces. The results described herein clarify the impact of interfacial interactions on block copolymer self-assembly and solidify an understanding of 0.5 L topography, which is frequently used to determine neutral surface compositions of considerable importance to contemporary technological applications.

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Section: Discussionmentioning

confidence: 99%

Structure, Stability, and Reorganization of 0.5 L₀ Topography in Block Copolymer Thin Films

et al. 2016

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“…The microphase-separated assemblies of block copolymers (BCPs) have gained increasing interest for lithographic applications in microelectronics, [1][2][3] nanophotonics, [4] and data storage. [5] By using perpendicular lamellar structures on high-χ BCP thin films, line and space (L/S) patterns with sub-10 nm facilitating the formation of perpendicular structures.…”

Section: Introductionmentioning

confidence: 99%

Direct In Situ Observation of the Early‐Stage Disorder–Order Evolution of Perpendicular Lamellae in Thermally Annealed High‐χ Block Copolymer Thin Films

Nakatani

Uchiyama

Seino

et al. 2019

Adv Materials Inter

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feature sizes and high aspect ratios for pattern transfer can be obtained. [6][7][8] Typically, such BCP thin films are prepared by spin-coating a dilute BCP solution onto silicon (Si) substrates. However, these as-cast BCP thin films exhibit a locally segregated, disordered morphology. [9][10][11] Although perpendicular lamellar structures can be obtained by various annealing processes, high defectivity in the resultant thin films reduces the potential for industrial applications. Furthermore, although chemical and physical guides can be used to alleviate the thin film defectivity, [6,[12][13][14][15] BCP thin films that can meet the industrial requirements of 0.01 defects cm −2 have yet to be developed.The difficulty in obtaining defect-free BCP thin films can be attributed to a lack of understanding and experimental documentation in the early-stage evolution of ordered structures and defects in perpendicular lamellar thin films. Previous studies on the evolution of ordered structures in thin films have focused on the formation of parallel lamellae with island-hole structures, [16][17][18] and late-stage defect dynamics, [9,[19][20][21][22][23][24][25][26] particularly using low-χ or parallel cylinder-forming BCPs. Capturing the real time evolution of perpendicular lamellae in situ has been difficult as BCP selfassembly tends to occur in shorter time frames than most characterization equipment can analyze the thin films and the fact that parallel structures tend to form due to interfacial selectivity at the substrate and free surfaces. However, by utilizing newer technology such as high-speed atomic force microscopy (AFM) equipped with a heating unit for in situ characterization of the annealing process in a wide temperature window from room temperature to above the glass transition temperature (T g ) of the BCP, the self-assembly behavior of BCP thin films can be documented in real time and space. Additionally, although differences in the surface free energies (SFEs) between the BCP components tend to induce the preferential interfacial segregation of one block, by balancing the surface affinities of both blocks or introducing chemically modifying layers to tune the chemical affinities of the interfaces, the selective segregation of one block can be prevented, The evolution of well-ordered, sub-10 nm, perpendicular lamellae from a disordered state is documented directly using in situ atomic force microscopy, cross-sectional scanning electron microscopy, and grazing-incidence small angle X-ray scattering. Since block copolymer (BCP) self-assembly occurs on extremely fast time scales, directly imaging the growth of perpendicular lamellae remains challenging. The lack of understanding behind early-stage self-assembly and how metastable defects can affect the kinetic behavior near thermodynamic equilibrium prevents the realization of defect-free thin films. By characterizing the evolution of nanostructures using a high-χ, perpendicular lamella-forming BCP, poly(polyhedral oligomeric silsesquioxane)-blockpoly(2,2,2...

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“…The micropatterning of BCPs was also investigated by employing photoactive species containing lithography. [30][31][32] This PR-free patterning has the advantage of not including PR removal and independent alignment of BCPs from the shape of micropatterns. However, it is difficult to control the alignment of nanopatterns in the micropatterned area, resulting in the ordered structures in a relatively short-range.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of gold nanowires in micropatterns using block copolymers

Kim

2018

RSC Adv.

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In this work, we introduce a facile method for fabricating well-aligned gold nanowires in a desired microstructure by combining the shear alignment of block copolymer (BCP) cylinders with a conventional lithography process. The aligned line patterns in a long-range order were firstly created with the shear alignment of cylinder-forming polystyrene-block-poly(2-vinylpyridine) thin films; then, gold was loaded to create metal nanowires. We directly employed photolithography on the nanopatterns, which simplified many fabrication steps. Furthermore, the combination of BCP assembly and photolithography allows for the independent control of nanopatterns and micropatterns, providing an opportunity to increase the nanopatterns' versatility. Fig. 1 Schematic illustration of overall process for fabrication of Au line patterns in microstructures. (a and b) Shear was applied on BCP thin films and Au ions were loaded. (c) Photolithography process was directly performed on the shear aligned thin films, which created micropatterns on BCP thin films. (d) Followed O 2 RIE process and (e) lift-off revealed the aligned nanopatterns in microstructures.This journal is

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Photopatterning of Block Copolymer Thin Films

Cited by 24 publications

References 107 publications

Structure, Stability, and Reorganization of 0.5 L₀ Topography in Block Copolymer Thin Films

Structure, Stability, and Reorganization of 0.5 L₀ Topography in Block Copolymer Thin Films

Direct In Situ Observation of the Early‐Stage Disorder–Order Evolution of Perpendicular Lamellae in Thermally Annealed High‐χ Block Copolymer Thin Films

Fabrication of gold nanowires in micropatterns using block copolymers

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Photopatterning of Block Copolymer Thin Films

Cited by 24 publications

References 107 publications

Structure, Stability, and Reorganization of 0.5 L0 Topography in Block Copolymer Thin Films

Structure, Stability, and Reorganization of 0.5 L0 Topography in Block Copolymer Thin Films

Direct In Situ Observation of the Early‐Stage Disorder–Order Evolution of Perpendicular Lamellae in Thermally Annealed High‐χ Block Copolymer Thin Films

Fabrication of gold nanowires in micropatterns using block copolymers

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Structure, Stability, and Reorganization of 0.5 L₀ Topography in Block Copolymer Thin Films

Structure, Stability, and Reorganization of 0.5 L₀ Topography in Block Copolymer Thin Films