The influence of heat treatment on the mechanical properties of DLC deposited by FIB-CVD were examined. To evaluate the mechanical properties, Young′s modulus and Vickers hardness were measured by the nano indentation tester. The microstructures of samples were characterized by HRTEM equipped with EELS. From results of the indentation experiments, it was found that Young′s modulus and Vickers hardness decreased with increasing heat treatment temperature. Analysis of EELS spectra indicated that the decrease in Young′s modulus and hardness was caused by the decrease of sp³ fraction.

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Scratch tests on diamond-like carbon (DLC) coatings deposited by focused ion beam chemical vapor deposition (FIB-CVD) process on Si, Ni, WC substrate were carried out using a nano-scratch tester. Tested specimens were observed by SEM and AFM to determine critical loads. The results showed the DLC films on WC, Ni substrate were delaminated by 18 and 6 mN loadings, respectively. On the other hand, no delamination was observed on the DLC film on Si substrate. From the critical loads and observations, it was shown that bonding of the DLC on the substrate was the strongest on Si, and the WC substrate showed higher properties than Ni one.

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Diamond-like carbon (DLC) has many good property as a high wear-resistant, low friction coefficient, a high mechanical hardness, gas barrier, chemical inertness. And now DLC films have very various applications as protective coatings in areas, such as magnetic strage disks, dies and plastic bottles. This research aims high speed deposition and selective deposition of DLC films by magnetron CVD method. Magnetron CVD is plasma enhanced CVD with magnetic field around substrate. Deposition rate of DLC films by magnetron plasma CVD method is more than fifty-fold larger than that of plasma CVD method. The magnetic field aroud the substrate was analyzed.

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Deposition of Diamond-Like Carbon (DLC) films at atmospheric pressure is important to achieve inprocess coating and free from work sizes. This research is aimed at the synthesis of the DLC film under the atmospheric pressure by the nanopulse CVD method using power source system that consists of a static induction (SI) thyristor. In this report, we paid attention to the amount of career gas, and confirm the deposition of DLC films under the atmospheric pressure under 30% gas mass flow in which already reported. Moreover, we report deposition of using nitrogen for the career gas.

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This study focuses on the deposition of high-density a-C films at high growth rates by vacuum arc deposition. In order to decrease droplets, discharge voltage, electric charge and structure of an arc discharge gun were examined. As a result, higher discharge voltage enabled higher growth rates. There was the optimal range of electric charge corresponding to the discharge voltage to decrease droplets. XPS analysis indicated that the ratio of sp3 bonding in a-C films was about 80% causing high-density of about 3.0g/cm3. Moreover, the structure of an arc discharge unit with short distance between edge of anode and discharge point decreased droplets in thick a-C films.

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It has been said that the reaction of Spin-on Glass(SOG) materials caused by the heat treatment and by electron beam irradiation is almost the same behavior by using of Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy(XPS) analysis. But, in this work, it was found that the difference between the reaction of SOG by the heat treatment and by electron beam irradiation with the analysis of the thermal desorption spectrometry(TDS).

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It is well known that a sputtered metal film grows with inclined columns when the incident angle of sputtered particles to the substrate inclines. This phenomenon is usually explained by so-called self-shadowing effect. We have shown that the novel structured film, such as zigzag and/or spiral columnar structure along with the growth direction, can be grown by changing the incident angle of sputtered particles during deposition. The relationship between sputtering conditions and film structures has also been investigated.

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We have studied Ge islands on glass substrates as a seed for the growth of polycrystalline Si thin films and proposed a new process for controlling their size and density. Self-assembled crystalline Ge islands were formed by solid-phase crystallization (SPC) of amorphous Ge thin films on glass substrates. By annealing the samples under oxygen ambient over 350°C, Ge islands were etched to form volatile GeO species (oxygen etching). Our results showed that Ge islands with good crystallinity and controlled in small size and low density were fabricated on glass substrates by the simple process combining SPC and oxygen etching.

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High-quality polycrystalline Si films on insulating substrates have been expected to realize high-performance thin-film transistors(TFTs) and solar cells. In this study, we proposed a new process to control size and density of Ge islands for formation of polycrystalline Si thin films on glass or SiO₂ substrates. We investigated crystallization of a-Si on Ge islands and found that crystalline Ge enhanced crystallization of a-Si on SiO₂. We have demonstrated that this process has a great advantage in crystallization tenmperature and time for obtaining large-grained poly-Si films.

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Using atmospheric pressure plasma chemical vapor deposition (CVD), extremely high-rate deposition of hydrogenated amorphous silicon (a-Si:H) films for photovoltaic layers of thin film solar cells were performed. Relationship between each deposition parameter and the film properties was studied. Optimizing the input power, photoconductivity of the film because almost constant and greater than 10-5Ω-1cm-1 in the range of deposition rate from 24 to 336 nm/s. Based on the results, the a-Si:H films were applied to the i-layers of p-i-n single junction solar cells. As a result, a normalized efficiency of approximately 85% was obtained for the a-Si:H solar cell of which i-layer was prepared at the very high deposition rate of 128.1 nm/s.

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Nowadays, Laser technology is located in the centre of optical engineering and industrial production technology. It is certain that laser processing has caused a revolution in the way of production technology not only thermal process of materials but precise process or ablation process for micro-process. Laser processing technology is still bringing a rapid expansion of new industrial applications. Here, it may be said, we have rushed into the second generation of laser processing. In these circumstances, technical trends of laser processing and leading-edge laser technologies are introduced in detail. And also, the views on the future of this field are described.

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In a laser forming, the plate usually bends to the laser-irradiated side. A method to bend a plate toward the opposite side of laser-irradiated surface is proposed in this report for the purpose of the control of the bending direction. The experiments of CO2 laser forming of Mg alloy plate were carried out under the condition of heating the opposite surface of the laser head. It was confirmed that the plate bended steadily toward the opposite side of laser-irradiated surface by heating, while the bending direction changed at random in the case of non-heating.

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Laser forming based on buckling mechanism is important for practical use because the forming of thin plates is caused due to the buckling. In the present experiments, the bending of thin plate is made using line laser beams. The experimental results show that the bending direction can be controlled by controlling the bombardment method of line beams.

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Deformation characteristics of plastic material in YAG laser forming were investigated using squared multi-mode laser beam. Larger bending angle could be obtained, when the temperature of the specimen surface was close to melting point of specimen. Optimum laser irradiation condition could be found by numerical analysis for obtaining large bending angle. Besides, in the case of plastic material, specimen is easy to deform more than the heat deflection temperature under load. Thus, the heat deflection temperature under load had a great influence on deformation characteristics. Specimen was deformed largely after laser scanning, when the temperature of specimen surface at the start point of laser scan was still above the heat deflection temperature under load.

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A thin stainless steel is bended by the irradiation of CO₂ laser. Then both temperatures at irradiated and opposite surfaces are measured using two sets of the two-color pyrometer with an optical fiber. In this study, we investigate the effect of temperature difference between irradiated and opposite surfaces on deformation mechanism. The increase of diameter of laser beam and the decrease of thickness of material make the temperature difference smaller and change deformation mechanism from Temperature Gradient Mechanism (TGM) to Buckling Mechanism (BM).

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Excimer laser is expected for micro-nano processing from now on, too. Before groping for the practical technology, it is necessary to know the fundamental character of processing. So, we have investigated the character of processing to the various materials by the ArF laser. We report about it because we processed polymer and metal.

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Fundamental cutting characteristics of solid type board, which was composed of copper lead frame and epoxy resin molding compounds, by SHG:YAG laser were experimentally investigated. Almost equal cutting speed could be obtained by this laser cutting technique compared to current dicing method using grinding blade. However, the spatter adhered to terminal increased with increasing laser power and feed rate. This spatter could be decreased by cutting from the resin side, and the damage of terminal could be reduced. On the other hand, resin material was excessively removed compared to copper lead frame, since the thermophysical properties of composite material was different in leaser irradiation direction. However, this difference of removal between copper and resin could be improved by controlling the feed rate.

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In the production of a mounted wheel, a super abrasive stone before sintered is drilled mechanically for inserting a grinding head axis. In this study, a pulsed Nd:YAG laser is used to make a small hole for an axis, and CBN and diamond stones sintered are used as work material. The cutting characteristics of the super abrasive stone are studied for the improvement of the productivity. The super abrasive stone of 5mm in thickness can be cut precisely and there is no chipping at the edge. The heat-affected zone produced by laser irradiation is effective for bonding the axis into the wheel.

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It is difficult to process a magnet. When magnets are manufactured, materials are processed into simple shapes, and then they are magnetized. However, if magnets are processed after magnetization, the speed of the product development will be improved, and the cost of the product development will be reduced because magnets will be distributed in the secondary market in the same way ordinary metals are distributed. If magnets of complicated shape can be made easily, its range of application will spread. In this study, we research about the way to process magnet by YAG laser, and investigate the heat affection by laser on the magnetization.

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The experimental study on laser welding of shape memory alloy (SMA) was conducted. The SMA and stainless steel wires of diameter 0.5 mm were used as the specimens to be welded. Two wires were set in a jig system, which holds wires in a semi-circular contour shape, and a pulsed YAG laser beam was irradiated along the borderline of the wires. It was found that laser welding can apply shape-memory function on the welded specime.

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Projection welding of magnesium alloy plates and pins of aluminum alloys is carried out. Weld properties are obtained by torque tests and observation of weld cross sections. They depend not only on the welding conditions such as compression force, welding duration and current, but also on the target surface conditions and kind of pin materials.

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Recently, attention is paid to the Al alloy that has the feature with lightness and recyclability by the viewpoint of the environmental conservation each field. In this research, the Al base alloy was welded by using the two YAG laser beams. Generally, the cracks and the defects such as porositing occur easily in the weld with one pulse laser. Therefore, higher-quality welding was developed by synthesizing the laser of a continuous wave. For that reason the laser beams with different oscillation method were combined, and the device that was able to weld the laser beams that had each feature was produced. And, efficacy was shown though it compared with the single laser welding.

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The welding defect, such as porosity or blowhole, was investigated by analyzing the welding sound generated during Nd:YAG laser spot welding of stainless steel sheets (SUS304). Laser beam conditions are the energy of 1.5, 3.3 J and pulse duration of 3.0, 8.0 ms, respectively. The welding is done on plate by single pulse. The Short-Time Fourier Transform (STFT) analysis is applied for obtaining the time dependence of the generated sound. It is classified into the intensity of the frequency region of 11 to 18 kHz (HFR) and that of four to 11 kHz (LFR) on all the analyses. When the intensity of LFR was stronger at the last stage of laser irradiation than that of HFR, the defect arose. On the other hand, it was not produced when the relation is opposite. And also, it was discussed about the cause of generating of HFR and LFR.

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CO₂ laser beam was applied to the cladding of stainless steel on cast iron by a preplaced powder method. The hardness and microstructure of the clad layer were investigated by changing the power of laser, number of clad layer. The average hardness of the clad layer was 180-220 HV0.1 under the following cnditions: laser power of 2400 W to 3200 W, cladding speed of 400 mm/min. The microstructure of clad layer showed a fine dendrites of which secondary dendrite arm spacing is 5 μm because of their rapid solidification. Heat affected zone was produced near the clad layer on the cast iron and their martensitic structure was observed.

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This research is an irradiation of the UV laser by setting up a metal target in a CO₂ critical fluid cell. The temperature of CO₂ critical fluid was operated a temperature of below critical point(20.0°C), a temperature of critical point (31.1°C), and a temperature of more than a critical point(33.0°C). Al , Ni and Si were used for target. The focal length was 0.5mm from the target surface. After the laser irradiation, nano structures of a metal, a metal oxide and the carbon were discovered from surface of the target. The nano structures were analyzed with the scanning electron microscope and X rays of energy analysis device.

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Hydrogen passivated Si(100) surface is patterned by KOH etching after mask formation by focused laser scanning. Control of the pattern width has been studied in this report. At the beginning, effect of the distance from the beam waist to the surface is examined. As a result, the pattern width decreased with the distance increased. When the surface was far away from the waist, the masks were damaged during etching. The width reduction suggests that the etch mask is not formed photochemically because if mask formation occurs at certain light intensity or fluence, the pattern should be widest when the light beam is defocused. Pattern width formed after repeated scanning was secondly investigated. As a result, the pattern width increased with the number of the scanning increased. Chemical resistance of the mask also became higher with repeated scanning. Finally, narrow and angular patterns have been realized by setting the surface away from the waist and scanning several times.

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In this study, laser peening of TiNI Shape Memory Alloy was examined. Vickers hardness of peening area after 10pulse laser irradiate was increased about 10%, however ablation phenomenon was shown on the surface with increasing number of laser pulse.

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Surface periodic structures can be formed on various kinds of materials using linearly polarized femtosecond laser pulses with low fluence that is slightly above the ablation threshold. Scratch tests were performed to investigate the influence of the periodic structures on adhesiveness of diamond-like carbon (DLC) film to stainless steel and cemented tungsten carbide. It was found that the periodic structures showed remarkable effect on improving adhesion between DLC film and its metal substrates.

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By choosing proper conditions, an intense pulse laser can clean a surface effectively without any damage on a base material. We have studied the laser cleaning process under water by time-resolved imaging technique, which uses two Nd:YAG lasers and a CCD Camera. Stainless steel plates covered by oxide layer are used as samples. Laser cleaning in air and under water conditions are imaged. A shade streak is observed on the laser axis inside but not outside of shock front in water. Some images seems to show blow-off of the oxide layer but not so clear yet. Formation of a bubble at laser-irradiated position starts at about 10 μs, becomes larger and then vanishes at 700 μs.

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Short and high power laser pulse can process the surface and the inside of transparent materials by focusing the pulse at a desired position. Here we report about the interaction of a Nd:YAG laser to PMMA and epoxy resin which are observed by an imaging system with nanosecond time resolution. The system uses 1064nm and 532nm of a Q-switched Nd:YAG laser as a processing laser and 532nm of another Nd:YAG laser as illuminating light. We observe shock waves which propagate into the material and into the atmosphere by both shadowgraph and photoelasticity images. Permanent damages generated in the sample are also seen in the images. Absorption of the energy of the focused laser pulse occurs at both the surface and the inside of the sample. When the 1064nm and 532nm light are irradiated to the sample, the portion of surface-absorbed energy is greater for 532 nm light absorption. In epoxy resin, however, 1064 nm pulses generate permanent damages while 532 nm pulses induce transient contrast without damage. Distribution of the stress in the sample can be seen in detail for epoxy resin by phtoelasticity image.

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A femto-second laser is a promising tool in precise micromachining with little heat affected zone. In the ultra-short pulse laser machining, however, there are many problems to be solved and the process should be examined in detail. In this paper, we have developed a fast imaging system which is applicable to the femto-second laser process and observed the femto-second laser drilling process of glass, silicon and metals with pico-second time resolution. The imaging system and the time-resolved observation results are described.

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The behavior of assist gas flow in the groove of different material thickness was investigated. Based upon the real shapes of cutting grooves, simulation model was established using the CAD drawings. The cross section in the direction perpendicular to the cut have a throat at both side walls in the groove owing to the effect of focal position. The simulation results shows that these throats can make accepted the assumption of the equation of continuity of gas flow under the boundary condition of walls in the groove. An assist gas behavior of jetting gas velocity and gas pressure in the cutting groove was estimated by simulation. And for ascertain the significance of the principle of conservation of mass in the condition, the mass flow rate was calculated using the theory of quasi-gas dynamics and actual measurement for an assist gas flow in the cutting groove.

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Laser micro-machining of Ag-Na ion-exchanged soda-lime glass was carried out using FHG of Nd:YAG nanosecond laser. The effects of penetration depth and distribution of Ag ions on optical transmissivity of ion-exchanged glass were investigated. The laser irradiation experiments onto highly Ag doped glass surfaces produced broad and shallow holes because of the high absorbance at the vicinity of surfaces. The high absorbance also causes the instantaneous ablation of target material during laser irradiation. It was, therefore, suggested that the ion-exchanged glass was very suitable for the defect-free laser micro-machining.

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We tried to drill a micro hole in a silica glass by means of UV laser with UV absorbent powder. We used cerium oxide powder as an absorbent. Absorbent powder was pasted on the glass surface, and a laser beam was shot on the glass surface. The glass should be cleaned and the powder should be pasted on the glass surface if we get a deep hole in the glass. Finally, we succeeded to drill a 200-micrometer-rectangular 2.5-millimeter-depth hole in a silica glass.

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Micro channels were fabrication by laser in a laminate film on a glass substrate, and produced the micro channel for blood test. A 3-pronged channel was fabricated using this method, and used for blood test. As a result, blood cells were lining up in one line. Moreover, the 3-pronged channel succeeded in observing of blood cells. In this research, we fabricated 3 liquid micro reservoirs before the 3-pronged channel, and liquid flow by a free falls by gravity like a sandglass. An ink was flow in the center of the 3-pronged channel, and pure water flowed both sides of it. As a result, ink flowed to center of the 3-pronged channel by gravity.

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A micro-channel is fabricated in resin by ultraviolet pulse laser ablation. A number of heat-hardening resin-films are layered on a soda glass. A laser fabricates a part of the channel on each film for every lamination. The channels are 45-180µm in depths and 50-200µm in widths. We fabricated two type micro-channels. One is a three-pronged micro-channel. The other is a capillary pipe inserted a three-dimensional channel. We tested these micro-fluidic devices for blood transportation and blood-cell flow and observation.

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The micro fluidic devices that observe the state of blood are developed. In this research, the micro fluid device that observes the state of blood is developed. A number of heat-hardening resin-films were piled up on a soda glass. A laser fabricated apart of the channel at each film on every lalmination, and then 3-D honeycomb structure and groove structure microchannel were fabricated. The channel sizes have widths of 10-300µm and depths of 30-90µm. Blood was injected into them. The aspect ratio and the distribution density of the hole were changed, and the flow of erythrocyte was observed with a microscope.

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Three dimensional microfabrication of silicon nitride ceramics was carried out by FHG of YAG-laser beam under flowing water. Laser ablation in the atmosphere resulted in the reattachment of debris that diminishes accuracy and appearance of products. The debris was removed by flowing water before accumulating on the surface of the sample and the processing reduced surface roughness. Additionally, influence of processing conditions such as energy fluence, laser pulse number, scanning rate and groove distance on processed shapes, accuracy and efficiency was investigated. These results enabled manufacturing of 3D structures with high accuracy.

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To expand the applicability of ion beam lithography by using highly charge ions, Ar¹⁺ and Ar⁹⁺ ions, whose energy was 90keV, were irradiated onto spin-on-glass (SOG) through a stencil mask. The fluencies of Ar ions were 1.6×10¹² and 3.1×10¹² atoms/cm². The step structure was fabricated on SOG by the chemical etching after the irradiation with Ar⁹⁺ as well as Ar¹⁺. The fluence and etching time dependencies of the etching depth has been observed. The step structure, whose depth is deeper than that at the beam center, was observed at the surrounding region. It is suggested from this result that the etching rate would be enhanced at fluence of Ar ions n < 1.6×10¹² atoms/cm².

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We describe the fabrication of carbon microstructures by laser-induced chemical vapor deposition. Carbon pillars were built by argon ion laser irradiation onto the substrate in hydrocarbon gases. In this research, ethylene (C2H4) was used. The density of the deposits was decreased with increasing the laser power. Cross sectional observation showed that the deposits had heterogeneous internal structure. Raman shift around the center of the deposits showed more similar spectrum as graphite than that around the cylindrical surface.

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We studied laser processing of carbon nanotubes that formed a paper of thickness 5μm to 10μm. A nanotube paper was formed from purified as-grown materials that synthesized by laser ablation method using Q switched pulse YAG laser. Laser processing was performed using cw Ar ion laser at the power of 0.6W with 514nm wavelength. Raman spectroscopy and FE-SEM results showed that nanotube bundle structure at laser irradiated area was changed when ambient gas was varied. And we found that carbon nanotubes are purified, and are aligned the direction by laser irradiation in air ambient.

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The purpose of this study is to investigate the ejected particles under CO2 laser cutting, to analyze the processing mechanism and to obtain the most suitable processing condition. It is found from the previous report that it is important to analyze the ejected particles from the view points of the laser cut surface roughness and the average diameter of ejected particles in various processing conditions. Therefore, in this paper it is clarified that the interaction between the amount of melted metal and the gage pressure of assist gas affects the average diameter of the ejected particles, and it is found that from the observation of the ejected particles under air cutting condition the atmosphere under laser cutting has an effect on the processing phenomena.

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A laser spray method, which is melting and ablating by 266 nm Nd: YAG laser in the air, has been developed. The carbon powder of 3 μm in diameter was used. Powders are feed by assist gas. The assist gas mixture used air and CO₂ gas. The focal lengths were 35 mm and 40 mm from the aluminum substrate. The film thickness was increased with decreasing CO₂ gas. The film was formed by moving stage. The deposit film ranges have length of 10 mm and wide of 2 mm. Deposited carbon coating on substrates were analyzed by scanning electron microscopy and X-ray diffraction analysis.

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Spin-On-Glass (SOG) and polymethylmethacrylate (PMMA) are used as a positive type electron beam (EB) resist whose depth is controlled by changing the EB acceleration voltage and EB dose. After the EB exposure, SOG was developed by buffered hydrofluoric acid (BHF) and PMMA was developed by mixed solution of isoamyl acetate and acetic ether. After the development, various etched depths were obtain by dose changing method, thus, 3-dimensional patterning of resist surface are possible using EB dose changing method.

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When irradiating the focused ion beam to quartz, exposing, and having developed it with the developer afterwards, the depth of 45nm was confirmed. It is thought that the irradiation effect with the ion made quartz meltable with the developer. Moreover, there is a feature that the processing speed is faster than the direct processing that uses the focused ion beam when the pit is formed. In this research, amount (μC/cm²) of doses is changed. It was tried to investigate the processing characteristic of quartz, and to find efficient processing conditions of quartz.

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This study is intended to fabricate a deep nanostructure on single crystal silicon by the combination of ion beam irradiation and wet chemical etching. The area irradiated by ion beams can be selectively etched in HF solution. The ion irradiation facility, which can produce and irradiate highly charged ion beams, is employed. The etching characteristics of irradiated area are investigated to control the depth of irradiated area using high-energy ion beams. Hereby, it can be known that nanostructures with several hundreds nanometers deep can be fabricated, and it can be controlled by adjusting the accelerate voltage. In addition, the solubility of irradiated area is quite a different according to the irradiating conditions. These results indicate a possibility of this method as a novel deep nanofabrication process.

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Components that make use of electromagnetic force increase in a recent automobile. For example, solenoidal parts to control pressure is adapted to transfer the drive force from engine to wheel. In this case, pure iron is used. Pure iron indicates good performance. But machinability of pure iron haven′t been studied well. In this study, machinability of pure iron was examined. The cutting force, the flank wear and the chip thickness were investigated to figure cutting mechanism. As a result, the flank wear of sintered carbide tip with coating decreases when the cutting speed increases.

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This study investigates the influence of tool materials (K10, PCD) and cutting conditions (Dry, MQL) on machinability such as cutting force, shape of chips, surface integrity and tool wear when orthogonal cutting tests of Zr-Al-Ni-Cu amorphous alloy are carried out under the various cutting parameters. As a result, it can be known that the shear angle is increasing to 45-or more, and chip thickness becomes more smaller than uncut chip thickness during the cutting speed increased. It is found that PCD tool is more effective to decrease the cutting force, and also, MQL cutting is excellent to improve the cutting surface and the decrease of the tool wear.

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Various two-dimensional cutting models, in which the mode of deformation consists of the line of velocity discontinuity, have been developed. By adding the uniform velocity along the cutting edge to hodograph in two-dimensional cutting, the cutting models are extended to represent the chip formation in oblique cutting. Upper bound approach is used for prediction of principal cutting force and chip formation such as chip flow angle and shear angle. The fraction of the cutting force acting on the rake face and on the dead metal is discussed. The cutting models applied to the drilling process in which the cutting velocity changes along the cutting edge. Using a quick-stopping device designed for use in a planer, the cutting action was frozen and the microscopic examination was made.

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In the case of a rounded cutting edge, unlike a sharp one, it makes the generation mechanism of the work hardened surface layer complicated. However, it is possible to predict it by using the ratio of the undeformed chip thickness to the cutting edge roundness. That is because the equivalent shear angle changes according to the ratio of the undeformed chip thickness to the cutting edge roundness.

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