Abstract: A numerical approach for forming simulation and manufacturing of micro part, based on the elastic and the rigid-plastic finite element methods by using grain element and grain boundary element, is proposed to simulate MEMS/micro-structural deformation behavior of material during micro forming. The idea is to present the polycrystalline material by an aggregate of so-called grain element that describes the plastic deformations of each individual grain in view of micro-structure. This grain element is connected by grain boundary element to account for shear deformation between
grains. The main objective in this study is to develop the reliable finite element model and scheme for micro forming simulation with very thin sheet. The reliability for micro forming analysis is described from the comparisons of the micro-structural deformation behavior between the conventional rigid-plastic finite element analysis and the FE analysis of the developed program with very thin sheet
Abstract: This paper presents a new method for fabricating 3D microstructures with an excimer laser micromachining system. A novel mask contour scanning method is developed for obtaining precise 3D microstructures with pre-described continuous surface profile. Two different microlenses with spherical and aspheric surfaces profiles with dimension less than 200 μm are fabricated on polycarbonate (PC) samples. The surface profiles are measured and compared with their theoretical
counterparts. Excellent agreements both in profile shapes and dimensions are achieved. The surface roughness (Ra) of the machined surfaces is also measured and is less than 10 nm. The machining profile accuracy and surface smoothness of this proposed micromachining method show great potentials in fabricating micro-optic components such as aspheric microlenses or microlens arrays.
Abstract: A high-sensitivity infrared detector requires small thermal capacitance and small thermal conductance to maximize the temperature change and signal induced by incident IR radiation. The suspended structure of infrared sensors provides ideal, thermally isolated, structures for support of the thin film detector. A new idea of improving CMOS thermopile performance is introduced to reduce the thermal conductance by dividing the thermocouple into several segments, which greatly increase the heat flow barrier. Then, adjacent segments are connected by a minimum width of alumina wire, which change the heat path and accumulated heat at the joint points. Several designs of infrared microsensors can improve performance of signal with reduce of thermal conductance. To that end, by using some adequate designs of polysilicon architecture, we can greatly reduce the heat flow from the
main stream without introducing further electric resistance, which is related with noise. The design and simulation of thermopile sensors are realized by using the process parameters of standard 0.351m CMOS IC technology. Firstly we develop such a structure of thermopile with low thermal conductance and high performance by using CMOS compatible process which can be easily and naturally fabricated. The simulation results show good match with our original idea and great performance than before.
Abstract: Nano-scale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) was demonstrated. A specially designed cantilever with diamond tip allows the formation of damaged layer on silicon substrate by a simple scratching process. A thin damaged layer forms in the substrate along scanning path of the tip. The damaged layer withstands against wet chemical etching
in aqueous KOH solution. Diamond tip acts as a patterning tool like mask film for lithography process. Hence these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. This study demonstrates the fabrication processes of the micro cantilever and diamond tip as a tool for TNL. The developed TNL tools show outstanding
machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool.
Abstract: Nanoimprint lithography (NIL) process at the room temperature has been proposed newly to achieve the shape accuracy and to overcome the sticking problem induced in conventional NIL processes. Success of the room temperature NIL relies on the complete understanding of the mechanical behavior of the polymer. Since a conventional NIL process has to heat a polymer above the glass transition temperature to deform the physical shape of the polymer with a mold pattern,
visco-elastic properties of the polymer have major effect on the NIL process. The rate dependent behavior of the polymer is also important in the room temperature NIL process because a mold is rapidly pressed onto the polymer while there has been no study on the rate-dependent NIL process. In this paper, finite element analysis of the room temperature NIL process is performed with the consideration of the strain-rate dependent behavior of the polymer. The analyses with the variation of
the imprinting speed and the imprinting pattern are carried out in order to investigate the effect of the process parameters on the room temperature NIL process. The analysis results show that the deformed shape and the imprinting force are diversified with the variation of the imprinting speed due to the dynamic behavior of the polymer with the rate dependent plasticity model. The results provide a
guideline to determine the process conditions in the room temperature NIL process.
Abstract: A new means of transducing mechanical force using a diffractive Bragg grating
based polymeric sensor is presented. The diffraction gratings are successfully fabricated on a polydimethylsiloxane (PDMS) polymer using the holographic interference and micromolding technique. The micro MTS tensile test incorporated with the Raman experiment showed that a relationship between the load and the observed diffraction pattern shift could be obtained. The results show an excellent correlation between the optical measurements and load with a sensitivity of 0.05N.
Abstract: This paper investigated the absorption of a micro-particle irradiated by laser.
Micro-particles usually appear within the plasma induced by a laser or powder in the process of laser cladding. These particles are assumed to be spherical and neutral (no surface charge). Laser-particle interactions involve scattering, refraction, and diffraction phenomena. Refraction and diffraction can enhance radiation absorption. The complex optical indexes of material and size parameters of
micro-particles characterize the absorption of particles in these materials processing. The electromagnetic wave theory and geometrical optics approach were utilized to analyze the absorption in the particle. The errors between these two methods were discussed for different indexes of absorption and size parameters. The compatibility of geometrical optics approach for a small particle
is also presented.
Abstract: It presented a novel manufacturing method that was derived from traditional hot embossing technology to fabricate actuators on polymer material in this paper. The conventional photolithography technology, electroplating, and hot embossing technology were utilized in this process. The plastic deformation properties of thermoplastic polymers were main concept. The metal layer deposited on the silicon wafer could be embedded into the polymer substrate by hot embossing
technology as temperature being above Tg. When the polymer substrate temperature was cooled below the Tg, the polymer is to de-embossing and remove silicon wafer. The metal layer was transferred from silicon wafer to be embedded in the polymer substrate. Owing to the adhesion between the metal layer and polymer material was more than the metal layer and silicon wafer. For instance, the PMMA was employed as the polymer substrate to fabricate the cantilever beam actuator
using the novel technology. Finally, the beam was driven by electrostatic force through 25volts of DC power.
Abstract: During depositing a thin film as a structure layer, residual stress from thermal treatment of depositing process will cause deformation after release. Thus the yield ratio and deformation of the devices may be lowered. This work investigates the effect of sacrificial layer on deformation by residual stress causing when depositing a thin film as structure layer. A model is established by using theory of plates-and-shells to investigate the deformation caused by residual stress when the structure
layers of the devices are center-anchored circular plate. Theoretically, it is found that the deformation would happen when depositing structure layer under higher temperature. And from the analysis, the thicker structure plate will cause less deformation. When the thickness of the structure layer is larger
than 3μm , the maximum deformation will reduce to the order of μm. Furthermore, four cases of different sacrificial layer types and temperature distribution with effect on deformation are discussed. If the thickness of the structure layer is above 5μm, the deformation caused by residual stress is not so important. And it is found that if the thickness of structure layer is 10μm order or above, the residual
stress effect on deformation can be neglected. It is found the sacrificial layer will affect the deformation. But it is found that with the same structure layer thickness, as the sacrificial layer thickness increasing, the four cases have different effect on deformation. The in-plane dimension effect is also considered. When the in-plane dimension of sacrificial layer is above 20 times of outer radius, the in-plane dimension effect is neglected and can considered as an infinite dimension.
Abstract: This article releases the details of the equipment development for the micro-anode guided electroplating MAGE fabrication. The microstepping architecture, electroplating power source, control system architecture, measurement system, man machine interface and the control prodedure will be described. Metallic columns around 100 micrometers in diameter were fabricated up to 2cm long with this equipment to demonstrate its performance. An innovative intermittent MAGE mode is
supported by this equipment so that it can produce micro columns of finer surface morphology and better circumferential uniformity than the conventional continuous electroplating.