Precise Synthesis of Fluorine-containing Block Copolymers via RAFT

Nakatani, Ryuichi; Takano, Hiroki; Wang, Lei; Tanaka, Yūki; Maeda, Rina; Kihara, Naoko; Minegishi, Shinya; Miyagi, Ken; Kasahara, Yusuke; Sato, Hiroki; Seino, Yuriko; Azuma, Tsukasa; Ober, Christopher K.; Hayakawa, Teruaki

doi:10.2494/photopolymer.29.705

Cited by 6 publications

(8 citation statements)

References 7 publications

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“…The lamella-forming PMAPOSS 6 - b -PTFEMA 80 ( M n = 18 300 g mol –1 , Đ = 1.13, f PMAPOSS = 0.31, d -spacing = 16.2 nm) was synthesized via RAFT as previously reported. , Thin films of PMAPOSS 6 - b -PTFEMA 80 were prepared by spin-coating 3 wt % chloroform solutions onto Si wafers and annealed on hot plates. To enhance the contrast in AFM measurements, PTFEMA segments were partially removed by reactive ion etching (oxygen, O 2 -RIE) (power: 20 W, O 2 flow: 20 sccm, time: 2 s).…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we designed a silicon- (Si) and fluorine-containing BCP, poly(polyhedral oligomeric silsesquioxane methacrylate- block -2,2,2-trifluoroethyl methacrylate) (PMAPOSS- b -PTFEMA) capable of forming sub-10 nm perpendicular lamellae on thin films using simple thermal annealing. − The χ eff of PMAPOSS- b -PTFEMA was estimated to be 0.45, one of the largest values reported to date. Additionally, the components exhibited balanced interfacial affinities relative to both the free surface and Si substrates at a wide variety of temperatures of around 100 °C.…”

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confidence: 99%

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Dynamic Ordering in High-χ Block Copolymer Lamellae Based on Cross-Sectional Orientational Alignment

et al. 2019

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Further development of next-generation block copolymer (BCP) lithography processes is contingent on comprehensive studies of the ordering dynamics of high-χ BCPs that can form sub-10 nm features on thin films. However, quantitative analyses of the degree of ordering on the surface and cross sections of thin films have been difficult to execute. To tackle this challenge, we employ a perpendicular lamella-forming high-χ BCP, poly(polyhedral oligomeric silsesquixone-block-2,2,2trifluoroethyl methacrylate) (PMAPOSS-b-PTFEMA), and reveal that the high-χ PMAPOSS-b-PTFEMA requires three times the activation energy (E a ) compared to that of poly(styrene-blockmethyl methacrylate) (PS-b-PMMA) for defect annihilation, at E a = 2600 ± 420 kJ mol −1 , and a transition from a fast ordering regime with a growth exponent of Φ = 0.30 at lower orientational order parameters (ψ 2 < 0.36) to a slow ordering regime with Φ < 0.05 at ψ 2 > 0.36, where well-aligned lamellae restrict defect annihilations to enthalpically unfavorable glide mechanisms that require BCP intermixing.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Dynamic Ordering in High-χ Block Copolymer Lamellae Based on Cross-Sectional Orientational Alignment

et al. 2019

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“…[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. [6,10,[27][28][29][30] Furthermore, earlier studies have focused on the self-assembly behavior of polystyrene-block-poly(methyl methacrylate) (PSb-PMMA). Despite being the industrial workhorse for BCP lithography, PS-b-PMMA has a low strength of segregation and is incapable of forming sub-10 nm features.…”

Section: Introductionmentioning

confidence: 99%

“…[6,27,30] The organic-inorganic blocks also increase the segregation strength and etch contrast between the blocks, allowing for the formation of sub-10 nm structures. The similar and low SFEs of both blocks (SFE PTFEMA, 19 °C = 24.0 mJ m −2 , SFE PMAPOSS, 19 °C = 30.4 mJ m −2 ) facilitate the formation of perpendicular lamellae on bare Si substrates without chemically modifying layers via simple thermal annealing.…”

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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“…PS-PMMA is the typical DSA material [5][6][7][8][9]. For smaller-size patterning, high-chi block copolymers are required [10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Hemicellulose Block Copolymers for Advanced Lithography Process

Morita

Yamamoto

Harumoto

et al. 2019

J. Photopol. Sci. Technol.

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Directed self-assembly (DSA) lithography is one of the promising next-generation lithography technologies. However, there are two main limitations to the use of DSA. One is the narrowness of the pattern size window and the other is the fabrication of the underlayer. To address the former limitation, wide-range DSA has been applied to expand the applicable patterning size while the latter has been achieved by utilizing the newly developed reactive hemicellulose hardening (R2H) technique. In R2H, the hemicellulose unit is selectively hardened by a chemical reaction. In this study, hemicellulose block copolymers for wide-range DSA lithography and its fabrication technology were newly developed. A hemicellulose high-chi block copolymer (OPAL-BCP) and its underlayer were fabricated using R2H. After reactive ion etching of the underlayer with R2H, a pattern depth of over 300 nm and etching selectivity of 24 were obtained.

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Precise Synthesis of Fluorine-containing Block Copolymers via RAFT

Cited by 6 publications

References 7 publications

Dynamic Ordering in High-χ Block Copolymer Lamellae Based on Cross-Sectional Orientational Alignment

Dynamic Ordering in High-χ Block Copolymer Lamellae Based on Cross-Sectional Orientational Alignment

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

Hemicellulose Block Copolymers for Advanced Lithography Process

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