Materials Science Forum Vols. 505-507

Abstract: The aim of this article is to introduce a nanowriter system that could lead to a sub-micrometer spot size using a visible light source under ambient conditions. The key component of the system is a focusing optical head, which incorporates a plasmonic-based lens instead of a conventional lens. Based on knowledge of the physical origin of extraordinary transmission and directional beaming, we theorize that the directional beaming phenomenon can be explained simply as a surface plasmon (SP) diffraction along the corrugations as long as the multiple scattering effects are taken into account to modify the dispersion relationship of the surface plasmon. We introduce a Rigorous Coupled Wave Analysis (RCWA) formulation to pursue a precise dispersion relationship needed for the lens design. Comparing the resultant theoretical data between Finite Difference Time Domain (FDTD) simulations and RCWA results, we found good agreement and the many important characteristic parameters needed for an innovative lens design. We also set up a writing-test optomechanical system to examine the photoresist exposure ability of the plasmonic-based lens.

Abstract: The paper describes the operation of a high-precision wide scale three-dimensional nanopositioning and nanomeasuring machine (NPM-Machine) having a resolution of 0,1 nm over the positioning and measuring range of 25 mm x 25 mm x 5 mm. The NPM-Machine has been developed by the Technische Universität Ilmenau and manufactured by the SIOS Meßtechnik GmbH Ilmenau. The machines are operating successfully in several German and foreign research institutes including the Physikalisch-Technische Bundesanstalt (PTB). The integration of several, optical and tactile probe systems and scanning force microscopes makes the NPM-Machine suitable for various tasks, such as large-area scanning probe microscopy, mask and water inspection, circuit testing as well as measuring optical and mechanical precision work pieces such as micro lens arrays, concave lenses, mm-step height standards.

Abstract: For the purpose of micro stage used in micro positioning, a miniature aerostatic air bearing linear slide system was studied. Different arrayed micro-hole plates were fabricated. Using focused laser drilling, the diameter of the hole is limited to 300m. However, with the MEMS process, smaller diameters up to 30m could be achieved. A miniature air bearing linear slide was constructed by imbedding three developed air pads in the slider block, which could slide along a small granite straightedge to form a small sliding stage. The pressure distribution of air pad simulated by the Spectral Element Method was found in good agreement with experimental results. It was also found that the smaller the micro holes the better stability of the floating condition can be obtained. Straightness tests of the developed miniature air bearing sliding stage are carried out to show its feasibility.

Abstract: The micro metal forming manufacturing system is essentially an ultra precision forming press that can manufacture various micro scale products from metal thin foil and bulk material. In this paper, the micro metal forming manufacturing system has been developed using a micro servo motor. A micro forming system has been developed in Japan with a micro press that is limited to the single forming process. However, a press with a multi forming process is needed and we set about performing research and development of assorted equipment, including investigation into micro deep drawing and the micro punching process. In order to achieve this goal, exploration into the micro forming process as related to the multi forming process must be preceded first. Material selection and analysis of the micro forming process are accomplished in this paper, and the basis research as to how to make the actual system is accomplished.

Abstract: This paper presents the development a drop-on-demand micro-dispensing system on which functional devices can be directly printed in a layer-by-layer manner that is commonly used in Rapid Prototyping and Manufacturing processes. The principle is to form micro droplets on substrate that requires accuracy and consistency with the ability to build 3D model. It requires heating of material to a desired temperature and viscosity which allows the piezoelectric the ability to pump out. In order to build a 3D model, a basic XYZ-axis gantry, motion controller and dispenser with temperature controller were developed and integrated. Experiments with different materials were carried out to understand the influences of the dispensing parameters on continuous frequency output. The results hold attractive potential for the use of this system in fabricating 3D models which meet the accuracy and resolution needs for various industry applications.

Abstract: This study presents an analysis of surfactant added by CuO and Al2O3 nano-sized particles of different percentages. After adding suspending nanocrystalline particles into lubricant of machines, the nano-sized particles will augment the heat transfer characteristics of fluids. Some former studies showed that such liquids pose a great potential for heat transfer enhancement. By applying nanofluids to heat transfer of machine lubricant, this paper attempts to explore dominating factors of heat transfer performance from various weight concentrations of nano-sized particles, the correlation among wall temperature, heat flux, rotational Reynolds number, Nusselt number, Grashof number and rotational Grashof number of four different concentrations. The results show that nano-sized particle lubricant offer a better heat transfer performance than typical lubricants. Since random movement and diffusing effect of nano-sized particles are one crucial factor for an increased heat transfer coefficient, adding 3.5% weight concentration nano-sized particle lubricant will produce an optimum heat transfer performance among Case I~IV.

Abstract: This research is aimed to fabricate glass fiber/epoxy nanocomposites containing organoclay as well as to understand the organoclay effect on the in-plane shear strength of the nanocomposites. To demonstrate the organoclay effect, three different loadings of organoclay, were dispersed in the epoxy resin using mechanical mixer followed by sonication. The corresponding glass/epoxy nanocomposites were prepared by impregnating the organoclay epoxy mixture into the dry glass fiber through a vacuum hand lay-up process. Off-axis block glass/epoxy nanocomposites were tested in compression to produce in-plane shear failure. It is noted only the specimens showing in-plane shear failure mode were concerned in this study. Through coordinate transformation law, the uniaxial failure stresses were then converted to a plot of shear stress versus transverse normal stress from which the in-plane shear strength was obtained. Experimental results showed that the fiber/epoxy nanocomposite exhibit higher in-plane shear strength than the conventional composites. This increased property could be ascribed to the enhanced fiber/matrix adhesion promoted by the organoclay.

Abstract: In this paper, we report a method for determining the residual thickness of resist layer during e-beam lithography processes. The method is based on the energy dispersive x-ray spectroscopic (EDS) measurements on a silicon substrate deposited with a PMMA layer. The PMMA layer acts as the resist layer in e-beam lithography. From a calibration test, an empirical relationship is established between the EDS signal, electron energy, and PMMA film thickness. Form this empirical relationship the residual PMMA layer thickness after e-beam exposure and developing can be determined within an accuracy of 83%, which is very important to the subsequent etching processes. An important feature of the proposed method is that its lateral resolution depends only on the focused e-beam spot size and can be in the order of nm. With such resolution, the thickness of the resist layer under few nm line width can be measured. The proposed method to estimate the residual resist layer thickness plays a vital role in nano-fabrication or nano-patterning based on e-beam lithography technology.

Abstract: The low-pressure control methods for an arc-submerged nanoparicle synthesis system (ASNSS) was proposed and developed for brake nanofluids. In the process, a copper bar is melted and vaporized in insulating liquid for core formation with crystallization suppressed to derive nanofluid that contains nanometer copper particles in DOT3 brake fluid. Two technical advances associated with nanoparticle synthesis were achieved. One is the novel pressure control technique developed for nanoparticle fabrication. The other is the verification that the constant low-operating pressure. Pressure operating plays important role in determining the characteristics of the prepared nanoparticles in brake fluids. From the experimental processes, pressure control of the ASNSS was identified as crucial to success of nanoparticles synthesis. To achieve the desired pressure control, a vacuum chamber was developed as a nanoparticle accumulator and low-pressure reservoir. The chamber was controlled by the proposed flow –valve feedback control system and integrated with the ASNSS. The pressure control equipment of the ASNSS was effectively developed to prepare desired copper-oxide brake nanofluids with well-controlled size.

Abstract: This study presents an innovative imprinting method to fabricate IC devices by micro-punch process. Normally, imprinting method is used to imprint plastic materials such as photoresist and polymeric materials. In this study, imprinting process is applied to micro-punch metallic materials directly for IC devices. Fabrications of IC devices with high aspect ratio structures ranging from micrometer to sub-micrometer are described. In this study, to keep the production costs as low as possible, a complete micro-punching process is applied to replicate IC devices. A combination of lithography, extra-hard alloy nickel cobalt (Ni/Co) electroplating process (as a metal imprint mold for punch) and chemical mechanic polishing (CMP) process is used to flat the extra-hard alloy micro-punch head. It is worth noticing that the Ni-Co electroplating process with hardness over Hardness of Vicker (Hv) 560 is developed. With such hardness, it can stand the high pressure and abrasivness to confine the accuracy during micro-punching process. With regard to the electroplating process, Ni-Co is deposited and covered on the photoresist template uniformly by electroplating. The Ni/Co mold is served as master for micro-punching process to replicate the pattern onto polyimide (PI) or copper sheets. Finally, the experimental results are measured and characterized.