Nano Plastic Forming Research Articles

超微細塑性加工と自己組織化を用いた光メタマテリアル用二層ロッド構造共振素子の開発

超微細塑性加工と自己組織化を用いた光メタマテリアル用二層ロッド構造共振素子の開発

Fabrication of plasmonic nanopillar arrays based on nanoforming

A new fabrication method for realizing ordered nanopillar array is reported in this paper. First, a metallic nanodot array is prepared by combining two techniques, viz., nano-grid patterning by Nanoplastic Forming (NPF) and dot agglomeration by thermal dewetting. These processes do not include complicated and expensive procedures such as electron beam lithography. Then Au-capped nanopillar arrays are produced by reactive ion etching (RIE). In the refractive index sensing application, it is shown that the sensitivity of the Au-capped nanopillar array is higher than that of the Au nanodot array. The plasmonic nanopillar arrays with Ag coating are used as SERS-active substrates, which exhibit good performance.

J2220202 超微細塑性加工と自己組織化を用いた光機能表面の開発

A new fabrication method of minute metal structures, which have optical properties of surface, on a quartz glass sustrate is reported in this paper. Minute metal structures are useful to develop metamaterials, which have artificial optical properties that have not existed in nature. The proposed fabrication method is a combination of Nano Plastic Forming (NPF) and self-organization technique by annealing. Firstly, gold thin film is deposited on a quartz glass substrate by DC spatter coater. Secondly, rectangle groove pattern is fabricated by NPF. Then, the substrate is annealed in an electric furnace to induce self-organization of he gold. Finally, SiO_2 spacer layer and gold thin film are deposited on this structure. In addition, optical extinction spectra are measured in the wavelength of visible light and near-infrared region. This structure shows high absorption peak at the wavelength of 966 nm. This absorption mechanism is discussed from the view point of electric circuit.

2505 Fundamental study on crystalline structure for development of functional surface

In this paper, functional surface development by controlling crystalline structure on surfaces of materials is suggested. In order to reveal the mechanism of crystalline structure change by Nano Plastic Forming method, plastic deformation characteristics of single crystal pure iron are examined experimentally by means of shearing tests. Stress-strain curves are measured and Critical Resolved Shear Stresses of activating slip systems are calculated based on crystal plasticity theory. Besides shearing tested specimens are annealed and crystalline structure are analyzed by EBSD for study of effects of microscopic plastic deformation and annealing on recrystallization.

Optical properties of ordered Dot-on-Plate nano-sandwich arrays

A cost-effective fabrication method for realizing ordered Dot-on-Plate nanostructure array is presented. This fabrication method is a combination of Nanoplastic forming (NPF) and thermal dewetting, which does not involve costly and complicated processes such as lithography. The fabricated Au–SiO2–Au sandwich nanostructures exhibit double plasmon resonances and strong magnetic response, which makes it a potential candidate for metamaterials. It is also found that the Dot-on-Plate nanostructure shows good performance as surface-enhanced Raman scattering (SERS)-active substrate. The milling of SiO2 spacer layer by dry etching is studied and the relation between the plasmonic properties and SERS enhancement is discussed.

Fabrication of an ordered nanodot array by thermal dewetting on a patterned substrate

Abstract A new process to fabricate an ordered gold nanodot array by thermal dewetting on a patterned substrate is proposed in this paper. Its feasibility was demonstrated through the experiments. The process comprises three steps; fabrication of a square nano-grooves grid on a substrate by nano-plastic forming, deposition of a thin gold film on the patterned substrate, and annealing the metal coated substrate to form an ordered nanodot array. The effects of the thickness of the deposited metal film on the morphology of nanodot array are studied. It is found that a nanodot array of good uniformity and regularity is obtained by optimizing the gold film thickness. It is verified that patterning of groove grid on a substrate is effective to improve the uniformity and regularity of the nanodot array in the thermal dewetting process.

Templated Thermal Dewetting Process by Utilizing Nano Plastic Forming Technology

A new nano manufacturing method to fabricate minute metal elements on a quartz substrate is reported in this paper. Such minute metal elements are useful to develop optical metamaterials, which have artificial optical properties that have not existed in nature. Proposed fabrication method in this paper is a kind of templated thermal dewetting, in which the Nano Plastic Forming technique is employed to fabricate templated patterns. Firstly, gold thin film is deposited on a quartz glass substrate by using a spatter coater. Then, an adequate groove pattern is fabricated using specially designed diamond tools. Finally, the substrate is annealed in an electric furnace to induce thermal dewetting. In this experiment, effects of annealing conditions and thickness of gold thin film on morphology of the aggregated gold film are studied. In addition, physical modeling of gold separation by thermal dewetting is studied. Through the experiments, possibility of Nano Plastic Forming technique on fabrication of nano metal element is discussed.

Optical Properties of Multilayer Ordered Gold Nanodot Array Fabricated by a Thermal Dewetting Method

A new efficient and low-cost method to fabricate multilayer ordered nanodot array is developed. In this method, firstly, a 2D nanodot array is fabricated by combination of Nano Plastic Forming (NPF) patterning of Au layer coated on the substrate and thermal dewetting induced self-organization. Then, multilayer ordered Au nanodot array is fabricated by repeating SiO2 deposition and Au deposition followed by thermal dewetting. Feasibility of this process was verified experimentally. The absorbance spectra of the fabricated ordered Au nanodot arrays show strong localized surface plasmon resonance (LSPR) with narrow bandwidth. It is shown that the absorbance spectra of a 2D nanodot array can be tuned by controlling annealing temperature. It is also found that intensity of the absorbance spectrum increases linearly with the increase of the number of layers. This enhanced absorbance gives rise to great potential in biosensing devices.

A New Process to Fabricate Three Dimensional Ordered Nano Dot Array Structures by Nano Plastic Forming and Dewetting

Three dimensional (3D) nano/quantum dot array structures have attracted more and more attention due to their broad applications. A new fabrication method of multilayer ordered nano dot array with low cost and high throughput is developed in this paper. This process is combination of Top-down and Bottom-up approaches: Nano Plastic Forming (NPF) patterning of metal layer coated on the substrate as Top-down approach and self-organization by dewetting as Bottom-up approach. Effects of process conditions on 3D nano-dot array formation are studied experimentally. Regularity and uniformity of first layer nano-dot array is transferred to the second layer nano-dots by optimizing thickness of the spacer layer and Au coating layer. Multilayer ordered nano dot array structures with good alignment are obtained by repeating coating and annealing processes.

Fabrication of multilayer ordered metallic nano-dot arrays by nano plastic forming and thermal dewetting process

A new fabrication method of multilayer ordered nano-dot array structures with low cost is developed in this paper. As for the first layer, ordered Au nano-dot array is fabricated by nano plastic forming and thermal dewetting, and then it is coated with a SiO2 spacer layer. Multilayer nano-dot structures are produced by repeating Au coating, dewetting and SiO2 coating process. Effective parameters influencing formation of the second layer dots including Au layer thickness and SiO2 spacer layer thickness are investigated. Mechanism of second layer dots formation is also studied. It is confirmed that regular 3D nano-dot array can be obtained by optimizing the thickness of SiO2 spacer layer and Au layer. Keyword: Nanofabrication, Nano Plastic Forming, Nano-dot

Nanofabrication of arbitrary patterns by nano plastic forming and etching (NPFE)

In this paper, flexibility of nano plastic forming and etching, an ultra-high resolution nanofabrication process developed recently by the authors, in terms of fabrication of arbitrary patterns as well as applicability to various work materials is demonstrated. First, a thin layer of nickel (Ni) is deposited on a silicon (Si) substrate. Then, it is directly patterned by nano plastic forming. Next, the patterned Ni mask is slightly etched by direct current sputter etching to transfer the pattern into the entire mask thickness and expose the surface of the substrate in the individual patterned areas. Afterward, the pattern is transferred onto the substrate by reactive ion etching. Finally, the remained Ni layer is removed from the substrate, and nanostructures fabricated on the surface of the substrate are revealed. Fabrication of grid patterns with various pitch settings on the surface of Si substrates is demonstrated. The experimental results indicate that the depth and width of the nanostructures can be controlled by the etching time. Also, it is confirmed from the results that the depth and width are not influenced by the pitch setting.

Rapid fabrication of an ordered nano-dot array by the combination of nano-plastic forming and annealing methods

In this paper, a new fabrication method for an ordered nano-dot array is developed. Combination of coating, nano-plastic forming and annealing processes is studied to produce uniformly sized and ordered gold nano-dot array on a quartz glass substrate. The experimental results reveal that patterning of a groove grid on the gold-coated substrate with NPF is effective to obtain the ordered gold nano-dot array. In the proposed fabrication process, the size of the gold nano-dot can be controlled by adjusting the groove grid size. A minimum gold nano-dot array fabricated on a quartz-glass substrate was 93 nm in diameter and 100 nm in pitch. Furthermore, the mechanism of nano-dot array generation by the presented process is investigated. Using a theoretical model it is revealed that the proposed method is capable of fabrication of smaller nano-dots than 10 nm by controlling process conditions adequately.

Fabrication of Ordered Gold Nano Dot Array by Nano Plastic Forming and Self-Assembly

A new fabrication method of ordered metal nano dot array is developed by using coating, nano plastic forming (NPF) and self-assembly due to annealing. In this study, the combination of these processes is studied to produce uniformly-sized and ordered gold nano dot array on a quarts glass substrate experimentally. The results reveal that patterning of lattice grooves on the gold-coated substrate with the NPF is effective to obtain the ordered gold nano dot array. In the proposed fabrication process, the size of the gold nano dot can be controlled by adjusting pitch of the groove. Furthermore, to investigate the effect of the NPF on the dot ordering, the multi-phase-field simulation of the self-assembly of the gold thin-film during the annealing is performed. From the simulation results, it is revealed that the grooves formed by the NPF become a starting point for the dot-formation during the annealing and the surface patterning by the NPF plays an important role for the fabrication of the ordered nano dot array.

3279 Development of Metallic Microstructure Control Method by using Nano Plastic Forming

In order to control microstructures in metallic materials precisely, we develop a new approach to control the metallic microstructures by using the nano plastic forming which can apply precise strain into the material and exact heat treatment. In this study, we investigate the statically recyrstallized microstructure in a single crystal copper formed by the nano plastic forming. The results show that dislocation cell and subgrain structure are generated by the forming. Furthermore, we can find that the nucleation and growth of the recrystallized grains are occurred from the deformed microstructures.

J111012 微細塑性加工と焼鈍による単結品金属の静的再結晶挙動([J11101]マイクロナノ理工学:nmからmmまでの表面制御とその応用(1))

In order to reveal static recrystallization in a single crystal metal, we investigate nucleation and growth behaviors of an individual recrystallized grain in a single crystal copper by using the nano plastic forming (NPF). First, the NPF which is a direct indentation of a diamond tool is performed to a single crystal copper. Then, the thermal annealing of the formed copper specimen is conducted to generate the static recrystallization. To clarify the plastic deformation and the static recrystallization behaviors, crystal orientation and dislocation microstructure in the formed specimen are studied by the electoron backscattered diffraction (EBSD) and the high voltage transmission electron microscopy (HVTEM). The results show that dense dislocation cell and subgrain structures are generated by the NPF. And, it is found that the nucleation and growth of the recrystallized grains from the subgrain structures are occurred.

3397 Finite-Difference-Time-Domain Analysis of Optical Properties of Ordered Nano-Dots Array Fabricated with Nano Plastic Forming

The optical properties of metallic nano-dots are widely used for various optical, electrical and biomedical devices. In this paper, the optical properties of the ordered gold nano-dots array fabricated with the nano plastic forming are investigated by experiments and the finite-difference-time-domain simulation. The simulation results demonstrate that the transmittance spectra of the ordered gold nano-dots array exhibit a unique light absorption behaviour due to the localized surface plasmon resonance and a clear red shift with increasing the diameter of the nano-dot.

J111031 微細塑性加工による規則的ナノドットアレイ形成のMulti-Phase-Fieldシミュレーション([J11103]マイクロナノ理工学:nmからmmまでの表面制御とその応用(3))

Recently, metal nano-dots array with unique electro and optical properties due to the localized surface Plasmon resonance have been used for various electromagnetic and biomedical devices. In order to improve their performance, it is essential to develop a new efficient fabrication method and to control morphology of the nano-dots array. In this study, the multi-phase-field simulation model is constructed to simulate formation of gold nano-dots array by our efficient fabrication method with the nano plastic forming (NPF) and annealing of gold thin-film. By the simulation method, we investigate effects of the grooves formed by the NPF and its pitch on the morphology of the gold nano-dots array.

T1602-3-3 超微細塑性加工と異方性エッチングを利用した微細溝加工([T1602-3]マイクロナノ理工学:nmからmmまでの表面制御とその応用(3))

In this paper, a new nanofabrication process is proposed to fabricate nanostructures on silicon substrate. The process utilizes metal coating instead of using resist mask. The metal layer is patterned using nano plastic forming (NPF) followed by sputter etching, instead of ultraviolet lithography or electron beam lithography patterning. Then the pattern is transferred into the substrate by anisotropic chemical wet etching. Finally, the excess metal layer is removed to reveal nanostructure on the silicon substrate. The proposed process was experimentally studied and arrays of nano trenchs narrower than 20 nm in width were fabricated on silicon (110) wafer.

T1602-1-2 Rapid Modification of Surface Optical and Wettability Properties Using the Combination of Nano Plastic Forming, Coating, and Roller Imprinting Processes

In this paper, the combination of Nano Plastic Forming, coating, and roller imprinting processes, abbreviated as NPF-CRI, is used to rapidly modify the surface functional properties of metallic material. Using this technique, four kind of different patterns are fabricated on the surface of pure aluminium (mirror finished, 99%). Using these patterns, the surface optical and wettability properties are evaluated. In terms of surface optical property, measurement results show that variationsin reflectance values are successfully observed on the fabricated patterns. As for the surface wettability, the contact angles of patterned surfaces are successfully modified and the possibility of controlling the shape of droplets on patterned surface using asymmetrical structure shapes is also shown. Based on these results, the capability of NPF-CRI technique to modify the surface optical and wettability properties by creating nano/micro structures is validated.

Nano/micro structure fabrication of metal surfaces using the combination of nano plastic forming, coating and roller imprinting processes

The fabrication technique using the combination of nano plastic forming, coating and roller imprinting processes to transfer nano/micro patterns onto the surface of metallic materials is developed. In this process, nano plastic forming (NPF) of pure aluminum (Al 99%) using a diamond tool is combined with a coating technique to produce a nickel die. The nickel die is then used for the double plate roller imprinting process to transfer the pattern onto the surface of metallic material. Experimental works with 0.1 N to 1.0 N indentation load variations and 2.5 µm to 7.5 µm pitch variations using a knife edge diamond tool are conducted to study the feasibility of this technique. Comparisons between the master mold, nickel die and rolling result in terms of geometries show good agreement, thus validating the proposed approach for high throughput, low cost, low emission and flexible fabrication technique. The capability of the proposed method is demonstrated in the fabrication of cross, net and brick patterns.