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C A Ross - One of the best experts on this subject based on the ideXlab platform.
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morphology directed self assembly and Pattern Transfer from a high molecular weight polystyrene block poly dimethylsiloxane block copolymer film
Nanotechnology, 2017Co-Authors: Lichen Cheng, Wubin Bai, George Liontos, Konstantinos Ntetsikas, Apostolos Avgeropoulos, Eduardo Fernandez Martin, C A RossAbstract:The self-assembly of block copolymers with large feature sizes is inherently challenging as the large kinetic barrier arising from chain entanglement of high molecular weight (MW) polymers limits the extent over which long-range ordered microdomains can be achieved. Here, we illustrate the evolution of thin film morphology from a diblock copolymer of polystyrene-block-poly(dimethylsiloxane) exhibiting total number average MW of 123 kg mol-1, and demonstrate the formation of layers of well-ordered cylindrical microdomains under appropriate conditions of binary solvent mix ratio, commensurate film thickness, and solvent vapor annealing time. Directed self-assembly of the block copolymer within lithographically Patterned trenches occurs with alignment of cylinders parallel to the sidewalls. Fabrication of ordered cobalt nanowire arrays by Pattern Transfer was also implemented, and their magnetic properties and domain wall behavior were characterized.
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universal Pattern Transfer methods for metal nanostructures by block copolymer lithography
Nanotechnology, 2015Co-Authors: Wubin Bai, George Liontos, Konstantinos Ntetsikas, Apostolos Avgeropoulos, C A RossAbstract:A universal block copolymer Pattern Transfer method was demonstrated to produce Co nanostructures consisting of arrays of lines or dots from a polystyrene-block-polydimethylsiloxane (PS-b-PDMS) diblock copolymer. Three processes were used: liftoff, a damascene process, and ion beam etching using a hard mask of tungsten, including a sacrificial poly(methyl methacrylate) layer under the PS-b-PDMS for the etch and liftoff processes. The ion beam etch process produced the most uniform magnetic arrays. A structural and magnetic comparison in terms of uniformity, edge roughness and switching field distribution has been reported.
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Orientation-controlled self-assembled nanolithography using a polystyrene - polydimethylsiloxane block copolymer
Nano Letters, 2007Co-Authors: Yeon Sik Jung, C A RossAbstract:Templated self-assembly of a cylinder-forming poly(styrene-b-dimethylsiloxane) (PS?PDMS) diblock copolymer has been investigated for nanolithography applications. The large ?-parameter of the blocks and the use of a PDMS?brush substrate surface treatment are especially advantageous for achieving long-range ordering and minimizing defect densities, and the high Si content in PDMS leaves a robust oxide etch mask after two-step reactive ion etching. By adjusting mesa width and solvent-annealing vapor pressure and time, the cylinders can be intentionally oriented parallel or perpendicular to the trench walls. Pattern Transfer into thin silica is also demonstrated. This block copolymer system has excellent characteristics for self-assembled nanolithography applications.
George M Whitesides - One of the best experts on this subject based on the ideXlab platform.
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improved Pattern Transfer in soft lithography using composite stamps
Langmuir, 2002Co-Authors: Teri W Odom, Daniel B. Wolfe, Kateri E. Paul, Christopher J Love, George M WhitesidesAbstract:Composite stamps composed of two layersa stiff layer supported by a flexible layerextend the capabilities of soft lithography to the generation of 50−100-nm features. The preparation of these stamps was adapted from a procedure originally developed by Schmid et al. (Macromolecules 2000, 33, 3042) for microcontact printing. This paper demonstrates how Pattern Transfer using other soft lithographic techniquesmicromolding in capillaries, microTransfer molding, and phase-shifting lithographycan be improved using two-layer stamps relative to stamps made of Sylgard 184 poly(dimethylsiloxane).
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microcontact printing of alkanephosphonic acids on aluminum Pattern Transfer by wet chemical etching
Langmuir, 1999Co-Authors: Laura B. Goetting, Tao Deng, George M WhitesidesAbstract:Microcontact printing (μCP) has been used to Pattern octadecanephosphonic acid on the native oxide surface film of aluminum supported on silicon or on silicon nitride-coated silicon wafers. The Patterned alkanephosphonic acid protects the Al2O3/Al film from etching in a solution containing phosphoric, acetic, and nitric acids and water in a ratio of 16:1:1:2 and allows the nonPatterned film to be removed selectively. The Patterned Al2O3/Al structures resulting from etching are continuous and electrically conductive within each Pattern, and separated Patterns are electrically isolated. Resistance measurements of the Patterned structures are presented. Using μCP, Schottky diodes of aluminum have been prepared on p-type Si(100). The Schottky diodes exhibit rectifying behavior, and the forward-bias current−voltage (I−V) and reverse-bias capacitance−voltage (C−V) characteristics are presented.
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Microfabrication of half-wave rectifier circuits using soft lithography
Sensors and Actuators A: Physical, 1999Co-Authors: Tao Deng, Laura B. Goetting, George M WhitesidesAbstract:Abstract This paper describes the fabrication of half-wave rectifier circuits using soft lithography. The fabrication process involved two steps of Pattern Transfer using micromolding in capillaries (MIMIC), and one step using microcontact printing (μCP); two steps required Pattern registration. This procedure, with its yield of ∼90%, demonstrates that soft lithography is compatible with multilayer fabrication, for this type of device. The characteristics at room temperature of the circuits generated using soft lithography were indistinguishable from those fabricated by conventional photolithography.
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nanometer scale Patterning and Pattern Transfer on amorphous si crystalline si and sio2 surfaces using self assembled monolayers
Applied Physics Letters, 1997Co-Authors: Dawen Wang, Younan Xia, Shawn G Thomas, Kang L Wang, George M WhitesidesAbstract:Microcontact printing was used to form nanometer scale Patterns of self-assembled monolayers (SAMs) on amorphous Si, crystalline Si, and SiO2 using octadecyltrichlorosilane (OTS) as the ink and an elastomer as the stamp. The Patterns were subsequently Transferred into crystalline Si substrates or amorphous Si films using the SAM of OTS as the resist film. Atomic force microscopy was used to characterize the quality of the SAM and the resulting Patterns. Using a Si pillar structure as the master, “pancakes” of less than 80 nm in size were formed by over etching of the Patterned OTS film on amorphous Si using KOH. The size of the resulting amorphous Si pancakes can be controlled by the etching time.
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Pattern Transfer to silicon by microcontact printing and rie
Nanotechnology, 1996Co-Authors: T K Whidden, D K Ferry, Michael N Kozicki, Amit Kumar, James L Wilbur, George M WhitesidesAbstract:Microcontact printing techniques employing self-assembled alkanethiol monolayers in the production of metal masks have been combined with reactive ion etch for subsequent Pattern Transfer to silicon. Silicon feature sizes of about 300 nm have been demonstrated. Some inadequacies in the self-assembled monolayers (SAMs)-formed metal masks have been characterized by electron microscopy. Particularly, nickel etch control and metal feature edge definition remain problems to be solved if the process is to be employed in submicron feature production. Nickel Patterns produced in the process and used as masks without the gold overlayer were successful as masks in the reactive ion etching (RIE) process. They also appear to give a somewhat improved edge definition over processes in which the gold layer remains.
Paul F Nealey - One of the best experts on this subject based on the ideXlab platform.
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sub 10 nm Patterning via directed self assembly of block copolymer films with a vapour phase deposited topcoat
Nature Nanotechnology, 2017Co-Authors: Hyo Seon Suh, Paul F Nealey, Dohan Kim, Priya Moni, Shisheng Xiong, Leonidas E Ocola, Nestor J Zaluzec, Karen K GleasonAbstract:Directed self-assembly (DSA) of the domain structure in block copolymer (BCP) thin films is a promising approach for sub-10-nm surface Patterning. DSA requires the control of interfacial properties on both interfaces of a BCP film to induce the formation of domains that traverse the entire film with a perpendicular orientation. Here we show a methodology to control the interfacial properties of BCP films that uses a polymer topcoat deposited by initiated chemical vapour deposition (iCVD). The iCVD topcoat forms a crosslinked network that grafts to and immobilizes BCP chains to create an interface that is equally attractive to both blocks of the underlying copolymer. The topcoat, in conjunction with a chemically Patterned substrate, directs the assembly of the grating structures in BCP films with a half-pitch dimension of 9.3 nm. As the iCVD topcoat can be as thin as 7 nm, it is amenable to Pattern Transfer without removal. The ease of vapour-phase deposition, applicability to high-resolution BCP systems and integration with Pattern-Transfer schemes are attractive properties of iCVD topcoats for industrial applications. A thin topcoat that grafts directly to block copolymer films does not need to be removed prior to further fabrication steps.
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integration of block copolymer directed assembly with 193 immersion lithography
Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials Processing Measurement and Phenomena, 2010Co-Authors: Paul F Nealey, Alex K Raub, Philip J Hakeem, Steven R. J. Brueck, Padma GopalanAbstract:An integration scheme of block copolymer directed assembly with 193 nm immersion lithography is presented. It is experimentally shown that a thin silicon nitride film can be used as an antireflective coating (ARC). With such an ARC, directed assembly of a block copolymer (BCP) to triple the feature density of a chemical Pattern was demonstrated. A high quality of assembly was obtained over a large area, and Pattern Transfer feasibility was illustrated. The integration of feature density multiplication via directed assembly of a BCP with 193 nm immersion lithography provided a Pattern quality that was comparable with existing double Patterning techniques, suggesting that the process could be a promising candidate for extending the use of current 193 immersion lithography tools to higher Pattern densities.
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Pattern Transfer using poly styrene block methyl methacrylate copolymer films and reactive ion etching
Journal of Vacuum Science & Technology B, 2007Co-Authors: Chichun Liu, Paul F Nealey, Yukhong Ting, A E WendtAbstract:Self-assembly block copolymers have drawn a lot of attention for its great potential on critical dimension (CD) control and line-edge roughness (LER) reduction, which become more and more crucial as the CD of transistors is only tens of nanometers nowadays. In this study, lamellar-forming poly(styrene-b-methyl methacrylate) copolymer which fabricates line Patterns was chosen for its ability to provide higher aspect ratio and vertical sidewall profile in template stage, thus more suitable for the following etching process to substrate. A dry plasma etching process using pure oxygen and pure argon plasma as example chemical etching gas and physical etching gas, respectively, was studied. Etching selectivity and lateral etch rate, which are responsible for the final template height and CD loss, had been characterized on a capacitive reactive ion etching tool. The templates formed by the proposed process had high aspect ratios, excellent Pattern fidelity, and low LER values. The PS lateral etch rate was small...
Paula T Hammond - One of the best experts on this subject based on the ideXlab platform.
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Pattern Transfer printing of multiwalled carbon nanotube multilayers and application in biosensors
Chemistry of Materials, 2010Co-Authors: Byeong Su Kim, Seung Woo Lee, Hyeonseok Yoon, Michael S Strano, Yang Shaohorn, Paula T HammondAbstract:We developed a simple, versatile technique to Pattern multiwalled carbon nanotubes on any substrate. This approach involves the multilayer assembly of multiwalled carbon nanotube (MWNT) suspensions...
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high density nanostructure Transfer in soft molding using polyurethane acrylate molds and polyelectrolyte multilayers
Nanotechnology, 2003Co-Authors: Youn Sang Kim, Hong H Lee, Paula T HammondAbstract:Here we present an alternative, new, unconventional lithographic technique developed to create dense and multilevel nanostructure Pattern Transfer using a highly accurate polyurethane acrylate (PU, MINS101m, Minuta Tech.) mold and a polyelectrolyte multilayer as the adhesion promotion layer. Specifically, we demonstrate the Pattern Transfer of periodic 80 nm lines with 400 nm height and complex and multilevel nanostructures to a polymer layer on various substrates, such as Si or SiO2 wafers, glass and flexible polymer films. This new, unconventional lithographic technique presented here would open the door to a variety of applications in the fields of electronic, optical and biological devices.
Grant C Willson - One of the best experts on this subject based on the ideXlab platform.
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directed self assembly and Pattern Transfer of five nanometer block copolymer lamellae
ACS Nano, 2017Co-Authors: Austin Lane, Gregory Blachut, Michael J Maher, Christopher J Ellison, Xiaomin Yang, Yusuke Asano, Yasunobu Someya, Akhila Mallavarapu, Stephen M. Sirard, Grant C WillsonAbstract:The directed self-assembly (DSA) and Pattern Transfer of poly(5-vinyl-1,3-benzodioxole-block-pentamethyldisilylstyrene) (PVBD-b-PDSS) is reported. Lamellae-forming PVBD-b-PDSS can form well resolved 5 nm (half-pitch) features in thin films with high etch selectivity. Reactive ion etching was used to selectively remove the PVBD block, and fingerprint Patterns were subsequently Transferred into an underlying chromium hard mask and carbon layer. DSA of the block copolymer (BCP) features resulted from orienting PVBD-b-PDSS on guidelines Patterned by nanoimprint lithography. A density multiplication factor of 4× was achieved through a hybrid chemo-/grapho-epitaxy process. Cross-sectional scanning tunneling electron microscopy/electron energy loss spectroscopy (STEM/EELS) was used to analyze the BCP profile in the DSA samples. Wetting layers of parallel orientation were observed to form unless the bottom and top surface were neutralized with a surface treatment and top coat, respectively.
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Directed Self-Assembly and Pattern Transfer of Five Nanometer Block Copolymer Lamellae
2017Co-Authors: Austin P. Lane, Gregory Blachut, Michael J Maher, Christopher J Ellison, Xiaomin Yang, Yusuke Asano, Yasunobu Someya, Akhila Mallavarapu, Stephen M. Sirard, Grant C WillsonAbstract:The directed self-assembly (DSA) and Pattern Transfer of poly(5-vinyl-1,3-benzodioxole-block-pentamethyldisilylstyrene) (PVBD-b-PDSS) is reported. Lamellae-forming PVBD-b-PDSS can form well resolved 5 nm (half-pitch) features in thin films with high etch selectivity. Reactive ion etching was used to selectively remove the PVBD block, and fingerprint Patterns were subsequently Transferred into an underlying chromium hard mask and carbon layer. DSA of the block copolymer (BCP) features resulted from orienting PVBD-b-PDSS on guidelines Patterned by nanoimprint lithography. A density multiplication factor of 4× was achieved through a hybrid chemo-/grapho-epitaxy process. Cross-sectional scanning tunneling electron microscopy/electron energy loss spectroscopy (STEM/EELS) was used to analyze the BCP profile in the DSA samples. Wetting layers of parallel orientation were observed to form unless the bottom and top surface were neutralized with a surface treatment and top coat, respectively
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double Patterned sidewall directed self assembly and Pattern Transfer of sub 10 nm ptmss b pmost
ACS Applied Materials & Interfaces, 2015Co-Authors: Julia D Cushen, Lei Wan, Gregory Blachut, Michael J Maher, Thomas R Albrecht, Christopher J Ellison, Grant C Willson, Ricardo RuizAbstract:The directed self-assembly (DSA) of two sub-20 nm pitch silicon-containing block copolymers (BCPs) was accomplished using a double-Patterned sidewall scheme in which each lithographic prePatterned feature produced two regions for Pattern registration. In doing so, the critical dimension of the lithographic prePatterns was relaxed by a factor of 2 compared to previously reported schemes for DSA. The key to enabling the double-Patterned sidewall scheme is the exploitation of the oxidized sidewalls of cross-linked polystyrene formed during the Pattern Transfer of the resist via reactive ion etching. This results in shallow trenches with two guiding interfaces per prePatterned feature. Electron loss spectroscopy was used to study and confirm the guiding mechanism of the double-Patterned sidewalls, and Pattern Transfer of the BCPs into a silicon substrate was achieved using reactive ion etching. The line edge roughness, width roughness, and placement error are near the target required for bit-Patterned media a...