The deformation distributions of carbon fiber reinforced plastics (CFRP) under a three-point bending load were nondestructively investigated using the phase shifting scanning electron microscope (SEM) moiré method. The complex fast Fourier transform (FFT) and the discrete Fourier transform (DFT) were used to filter the useless moiré fringes in the case of bidirectional moiré fringes. The SEM moiré fringes under different magnifications and the deformation results measured by the direct, complex FFT- and the DFT- phase shifting moiré methods as well as the moiré fringe centering method were compared and analyzed. Experiments demonstrate that the deformation measurement is a bit influenced by the useless moiré fringes in the phase shifting moiré methods and complex FFT processing works better for nondense moiré fringes. The relative strain changes gradually and the specimen grating pitch increases gradually from top to bottom along the loading direction, suggesting that the real compressive strain is greater in the upper side. The micro/nano-scale deformation distribution characteristic is helpful for better understanding of the mechanical properties of the CFRP specimen.
A method for measuring the stress and strain distribution in composite materials and the residual stress near the interface
in smart composite has been developed. The strains are measured using electron Moiré method. In this method a very
fine model grid is fabricated using the optical and electron lithography techniques on the surface of the specimen and an
electron beam scan of which the spaces are almost same as that of the model grid used for the master-grid. The
difference in the amount of secondary electrons per a primary electron produces the Moiré fringes that consist of bright
and dark parts. The residual strain and stress around the fibers of the smart composite materials and thermal expansion
ratio of a fiber and Al matrix were measured by this method.
KEYWORDS: Nanoparticles, Nanolithography, Electron beams, Scanning electron microscopy, System on a chip, Americium, Silica, Particles, Materials science, Scientific research
A new method to measure the spacing and direction in the ordered assembled nanoparticles by using the electron Moiré new method to measure the spacing and direction in the ordered assembled nanoparticles by using the electron Moiré fringes has been developed. In this method an assembled nanoparticle array can be consider as a model grid. When the electron beam was irradiated on the top of the nanoparticles, the amount of secondary electrons per primary electron is quite large. On the other hand, when the electron beam was irradiated on the valley among the neighboring nanoparticles, the amount of secondary electrons per primary electron is smaller. The difference of the generated secondary electrons per a primary electron fabricate periodical bright and dark pattern, which is the electron mesomoiré fringes. Using this method, the spacing and orientation of the assembled nanoparticle array was measured. new method to measure the spacing and direction in the ordered assembled nanoparticles by using the electron Moiré fringes has been developed. In this method an assembled nanoparticle array can be consider as a model grid. When the electron beam was irradiated on the top of the nanoparticles, the amount of secondary electrons per primary electron is quite large. On the other hand, when the electron beam was irradiated on the valley among the neighboring nanoparticles, the amount of secondary electrons per primary electron is smaller. The difference of the generated secondary electrons per a primary electron fabricate periodical bright and dark pattern, which is the electron mesomoiré fringes. Using this method, the spacing and orientation of the assembled nanoparticle array was measured.
fringes has been developed. In this method an assembled nanoparticle array can be consider as a model grid. When the electron beam was irradiated on the top of the nanoparticles, the amount of secondary electrons per primary electron is quite large. On the other hand, when the electron beam was irradiated on the valley among the neighboring nanoparticles, the amount of secondary electrons per primary electron is smaller. The difference of the generated secondary electrons per a primary electron fabricate periodical bright and dark pattern, which is the electron mesomoiré fringes. Using this method, the spacing and orientation of the assembled nanoparticle array was measured.
New methods to fabricate a metallic closed cellular material for smart materials using an isostatic pressing, spark plasma
sintering (SPS) method and penetrating method are introduced. Powder particles of polymer or ceramics coated with a
metal layer using electro-less plating were pressed into pellets and sintered at high temperatures by sintering at high
temperature. Also these powder particles were sintered by spark plasma sintering (SPS) method. Also a many kinds of
closed cellular materials with different materials of cell walls and different materials inside of the cell were tried to
fabricate. The physical, mechanical and thermal properties of this material were measured. The results of the
compressive tests show that this material has the different stress-strain curves among the specimens that have different
thickness of the cell walls and the sintering temperatures of the specimens affect the compressive strength of each
specimen. Also, the results of the compressive tests show that this material has high-energy absorption and Young's
modulus of this material depends on the thickness of the cell walls and sintering conditions. The internal friction of this
material was measured and the results show that this internal friction is same as that of pure aluminum.
A method to fabricate the metallic closed cellular material has been developed. Powder particles of polymer coated with a nickel-phosphorus alloy layer using electro-less plating were pressed into pellets and sintered at high temperatures by a furnace and a spark plasma sintering (SPS) system. A metallic closed cellular material containing different materials from that of cell walls was then fabricated. The mechanical properties of this material were measured. The results of the compressive tests show that this material has the different stress-strain curves among the specimens that have different thickness of the cell walls and the sintering temperatures of the specimens affect the compressive strength of each specimen. Also, it seems that the results of the compressive tests show that this material has high-energy absorption and Young's modulus of this material depends on the thickness of the cell walls and the sintering temperature. These obtained results emphasize that this material can be utilized as energy absorbing material and passive damping material.
In this study, the atomic force microscope( AFM) scanning moiré method is developed. The scanning lines in the AFM monitor are used as the reference grating. The reference grating interferes with the specimen grating, and forms a moiré pattern on the monitor. The formation mechanism of AFM moiré, the deformation measurement principle using this method are described in detail. The AFM scanning moiré method is used to measure the residual deformation of mica substrate after being damaged by the YAG laser, and the thermal deformation in a QFP type electronic package. The experiment results verify the feasibility of AFM scanning moire method and show its ability to measure the in-plane deformation in both micro-and nano-scales.
A technique for measuring the distance between the micro-device and substrate is developed. An electron beam scan of a scanning electron microscope used for this method. A micro-device is placed over the substrate and obstructs the back-scattered electrons from the substrate. Therefore, the shadow image of the micro-device is observed in the SEM image. The distance between the micro-device and the substrate can be calculated using the width of the shadow, dimension of the detectors for the back-scattered electrons and the dimension of the micro-devices. This method makes it possible not only to measure the distance between the micro-device and the substrate and also detect the form of the specimen surface. In addition, observation of the micro-devices and measuring the distance between the micro-device and the substrate can perform at the same time. As a demonstration, the distance between the micro-bar and the substrate and the shape of the micro-hardness tester's indent mark is measured.
New method to fabricate the metallic closed cellular material containing organic materials for the damping systems has been developed. Powder particles of polystyrene coated with a nickel-phosphorus alloy layer using electro-less plating were pressed into pellets and sintered at high temperatures by a furnace and a spark plasma sintering (SPS) system. A metallic closed cellular material containing polystyrene was then fabricated. The physical, mechanical and damping properties of this material were measured. The density of this material is smaller than that of other structural metals. The results of the compressive tests show that this material has the different stress-strain curves among the specimens that have different thickness of the cell walls and the sintering temperatures of the specimens affect the compressive strength of each specimen. Also, it seems that the results of the compressive tests show that this material has high-energy absorption and Young's modulus of this material depends on the thickness of the cell walls. The loss factor of this material was measured and the results show that this material has a large loss factor than that of structural metals. These obtained results emphasize that this metallic closed cellular material can be utilized as energy absorbing material and passive damping material.
A metallic closed cellular material containing organic materials for the smart materials has been developed. Powder particles of polystyrene coated with a nickel-phosphorus alloy layer using electroless plating were pressed into green pellets and sintered at high temperatures. A metallic closed cellular material containing organic materials was then fabricated. On the fabricated metallic closed cellular materials, compressive properties, Young's modulus, ultrasonic attentuation coefficient internal friction were measured. The compressive tests shows that this material has the different stress-strain curves among the specimens that have different thickness of the cell walls. Each stress-strain curve has a long plateau region, the sintering temperatures of the specimens affect the compressive strength of each specimen, and energy absorbing capacity is very high. Young's modulus of this material depends on the thickness of the cell walls and the sintering temperature. The attenuation coefficient of this material observed by ultrasonic measurement is very large. Internal friction of this material is very large and depends on the sintering temperaturer. These results indicate that this metallic closed cellular material can be utilized as energy absorbing material and passive damping material.
A metallic closed cellular material containing organic materials for the smart materials has been developed. Powder particles of polystyrene coated with a nickel-phosphorus alloy layer using electroless plating were pressed into green pellets and sintered at high temperatures. A metallic closed cellular material containing organic materials was then fabricated. The density of this metallic closed cellular material was measured. The density of this material is smaller than that of other structural metals. On the fabricated metallic closed cellular materials, compressive properties, Young's modulus and ultrasonic attenuation coefficient were measured. The compressive tests showed that this material has the different stress-strain curves among the specimens that have different thickness of the cell walls. Each stress-strain curve has a long plateau region, the sintering temperatures of the specimens affect the compressive strength of each specimen, and energy absorbing capacity is very high. Young's modulus of this material depends on the thickness of the cell walls and the sintering temperature. The attenuation coefficient of this material observed by ultrasonic measurement is very large. These results indicate that this metallic closed cellular material can be utilized as energy absorbing material and passive damping material.
A new material for damping and energy-absorbing has been developed using a powder particle assembling technique. Powder particles of polystyrene coated with nickel-phosphorous alloy layers using electroless plating were assembled and sintered at high temperature. A closed cellular solid structure containing polystyrene was then constructed. The mechanical and ultrasonic properties of this cellular solid were measured at room temperature and at high temperatures. The compressive tests show that Young's modulus of this cellular solid is very small as are the changes due to increasing temperature, and the cellular solids have a high energy absorption. Ultrasonic measurement showed that the attenuation coefficient of this cellular solid is very large and would change due to increasing temperature. These results indicate that this cellular solid can be used for energy absorbing and passive damping systems.
Process monitoring is now receiving more serious attention than ever before in an effort to increase the efficiency of equipment utilization and the stability of process quality in VLSI production lines. The objectives and effects of process monitoring are discussed in this article. The function of various process monitoring tools are also classified and examined in an effort to replace current PQC or inspection procedures. Several of the monitoring technologies developed by our research group are reviewed in detail. Stabilization of the metal deposition processes is thought to be effective in stabilizing the subsequent etching and photo processes. A sputter monitoring system in which essential process parameters are sensed in-situ is shown to be sensitive enough to detect process variations. W-CVD can be monitored by using quadruple mass spectroscopy (QMS) to provide real-time information about the onset of deposition reactions, etc. Simple time control of the deposition is not sufficient to control the process since the metal CVD reaction is susceptible to the surface state. Process tools can still be improved by the development and application of monitoring technology. However, on overall improvement in production efficiency should be attained through a good combination of process monitoring tools and a line control system.
KEYWORDS: Moire patterns, Scanning electron microscopy, Electron beams, Copper, Fringe analysis, Electron beam lithography, Metals, Electron microscopes, Process modeling, Gold
Microcreep deformations in pure copper specimens are studied by a new moiré method. In this method, a fine micrograting prepared by electron beam lithography is used as a model grating, and a scanning exposure ofthe primary electron beam in a scanning electron microscope (SEM) as a master grating. The scanning exposure of the electron beam on the specimen with the model grating produces moiré fringes of bright and dark lines formed in response to the different amounts of the emitted secondary electrons for each primary electron. This new method makes it possible to obtain a clear and fine moiré fringe without an image-processing system and to observe the moiré fringe pattern and the SEM image at the same time. By this method, the inhomogeneous microcreep deformations such as grain boundary sliding, coarse slip, and localized strain are measured with high accuracy. It is confirmed that the creep strain is nonuniform even in the same grain and the strain distribution is caused mainly by the grain boundary sliding.
A new Moiré method using a scanning electron microscope (SEM) for the measurement of micro-deformation has been developed. This new method makes it possible to observe the Moiré fringe pattern and SEM image at the same time. In this method, a fine microgrid prepared by electron lithography is used as a model grid, and scanning exposure of the electron beam in a SEM as a master grid. The exposure of electron beam on the specimen with the model grid produces Moiré fringes of bright and dark lines formed by the different amount of the secondary electrons. This fine Moiré fringe pattern is fine and clear enough to measure the strain distribution in a small area. By this method, concentrated strains around a small holes in polyimide resin specimens and also the inhomogeneous micro-deformations such as grain boundary sliding in copper specimens were measured, with high accuracy.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.