Chemical mechanical polishing (CMP) is a key process used for the multilayer copper interconnects. In recent years, the most common problem encountered in this regard is the inability of conventional abrasive grains to adapt to the nextgeneration semiconductors owing to their large particle sizes. Hence, this study proposes a water-soluble fullerenol (C₆₀(OH)₃₆) as a novel abrasive grain for Cu-CMP because of its advantageous features such as high water solubility and uniformity of particle size (1 nm); further, there is no risk of contamination of the metal when using C₆₀(OH)₃₆. In this paper, the excellent grain abrasive properties of C₆₀(OH)₃₆ and its chemical affinity for copper are reported. It is experimentally confirmed that owing to its high chemical reactivity, a slurry containing C₆₀(OH)₃₆ can be used to improve the rms surface roughness from 20 to 0.5 nm.

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Abrasive free polishing (AFP) for copper interconnects was improved. A chemical mechanical polishing (CMP) process using in two-step Cu AFP conditions eliminates copper residue. The process has a higher short-yield margin than the conventional AFP process. It uses both a high selective barrier metal slurry and a randomly foamed polyurethane pad to achieve the same Cu wiring sheet resistance as a conventional polishing process. However, this method allows for increased depressions of less than 20% on a 20-μm Cu line of 98% density after Cu-AFP. We demonstrate that the process can meet the planarity target without any extra intermediate oxide polishes. Moreover, it is the compatible with low-k films and the Cu AFP process, and this prevents delamination and fractures in low-k materials during CMP. Therefore, this process should meet the requirements for Cu interconnects.

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At first, I explain some key points and difficulty of lithography tool design, issues that should be overcome during the development and requirements for stages in lithography tool in this paper. Then, I have ascertained a limit of static-pressure air bearing with differential pumping mechanism for vacuum application, for instance EUVL(Extreme Ultra Violet Lithography tool) by manufacturing so-called the “vacuum compatible” 1-axis air bearing and verifying the performance by comparing with equivalent model simulation. Finally, one of MAGLEV(MAGnetic LEVitated) stage concepts is proposed instead of common AIRLEV(AIR LEVitated) stage by seriously considering a high throughput for mass production. I simultaneously contribute 2^nd paper, “Development of 6DOF Magnetic Levitation Stage for Lithography Tool -Proof Of Concept (Second Report)-“ which is a sequel to this paper.

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Spindle vibration of machine tools causes premature tool wear and deterioration of machining accuracy. The vibration of machine tool spindles changes depending on a used tooling system and rotational speed during various machining operations. Especially, in high speed machining, even small unbalance mass of the spindle makes large whirl. However, a real-time balancing mechanism for a machine tool spindle including a tooling system has never realized successfully. In this study, in order to reduce unbalance response of the spindle to achieve high accuracy and efficiency machining, a smart spindle with a real-time balancing mechanism using magnetic fluid is proposed. The magnetic fluid is enclosed inside the spindle, and the distribution of the circumferential mass is actively controlled. A test spindle with the real-time balancing mechanism was designed and developed in order to evaluate the control method of the magnetic fluid experimentally and to accumulate adequate information for the basic design of a machine tool spindle. The experimental results presented in this paper proved the feasibility of the proposed real-time balancing mechanism for a machine tool spindle.

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The least square circle method calculating shifts of center coordinates of concentric circles was developed in order to evaluate an overlay error for 3D microfabrication technology. This method consists of (1) SEM image capture of a truncated cone structure fabricated by multiple stacking of concentric circle patterns, (2) edge extraction of the circles and (3) calculation of the center coordinates by the least square fitting using matrix calculation software. The repeatability of the measurement method was examined by calculating the center coordinates of an identical SEM image for five times and that was better than 1 pixel in 3σ deviation. The calculation time was 5 min. for edge extraction for 80 points in 10 circles and less than 2 sec. for the calculation. This method was applied to evaluate the fabrication accuracy of FORMULA technology, which is our original 3D microfabrication technology using surface-activated bonding. The results showed that this method enables us to distinguish the random error from the systematic error of the fabrication.

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This study investigates the copying rate of tool motions to workpiece profiles. A machining system is developed to measure tool motions and workpiece profiles during machining processes. Tool motions are measured with a laser displacement sensor and an artifact. Workpiece profiles are measured by scanning type on-machine measurement. Sinusoidal profiles with various amplitudes are machined with a diamond tool to compare tool motions and workpiece profiles. The experimental result shows that the commanded motions and vibrations are copied on workpiece profiles. The ratios between the amplitudes of motions and profiles are calculated in the frequency domain to identify the copying rate. It is verified that the commanded motions are almost perfectly copied under the amplitudes of from 0.5 μm to 4 μm and the developed system is able to identify the copying rate under the amplitudes of from 0.5 μm to 1 μm.

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This paper describes the analytical method and result of run-out of an externally pressurized air bearing based on the profile error of spindle radial direction. Bearing clearance varies due to the profile error of the spindle radial direction, and an imbalance of pressure distribution occurs on a bearing. When the whirl of the spindle occurs run-out is caused by an imbalance in pressure distribution. In this study, the Finite Element Method (FEM) is used for pressure distribution on the bearing, and run-out is calculated from the force vector balance of pressure. A ridge spindle is proposed for the analysis and the experimental model to simplify the generation mechanism of the run-out. A measuring system that measures pressure distribution has been developed to confirm the accuracy of the result obtained from the analysis of pressure distribution. The analysis result is compared with the experiment using a system with rotational precision that is similar to a roundness measuring machine. The results of this study show that the run-out is caused by an imbalance of pressure distribution with profile error of the spindle radial direction. The profile error of the spindle that affects run-out has been confirmed by the analysis and experimental results. This study shows the validity of this analysis method due to the conformity of the analysis results and the experimental results.

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This study deals with new planning method of tool posture for continuous 5-axis control machining with ball endmill. In conventional planning method, tool posture is planned before post processing phase without consideration about fixturing and kinematics of machine tool. So, it is difficult to achieve dynamic synchronous accuracy among rotational axes and translational axes in high speed machining. In the proposed method, in order to put a limitation of acceleration on each axis, we propose a new representation method for tool posture planning, called as Mercator/Machine Map (M-Map). M-Map is defined by 2-dimentional rectangular coordinates system and each axis corresponds to rotation angles of two rotary tables in 5-axis controlled machine tool. And, each domain on M-Map is colored by the state about collision between endmill and workpiece surface and positions of three translation axes. In this paper, we mention about definition of M-Map and fast calculation algorithm of M-Map based on performance of graphics hardware (GPU). The developed prototype system can estimate the M-Map at arbitrary point on cutter location within dozens of milliseconds.

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The spray cleaning, a cleaning method to make fine liquid particles impinge with high speed, is now often used for sheet-feed cleaning of electronic devices. Here we have taken up two typical atomizing systems for spray cleaning tools, two fluid spray and high pressure micro jet, for the purpose to explicate mechanism to obtain adequate cleaning efficiency. Practically, in order to analyze behaviors of cleaning liquid particles sprayed out of two differently structured nozzles, we measured particles diameters as well as their flying velocity and, as index to show flying state of the particles, we newly took account of indicators of cleaning liquid transfer efficiency, which we measured in both systems. Also, cleaning tests were conducted on true spherical particles of polystyrene latex stuck on glass substrates to see cleaning efficiency. As results, it is confirmed that, while cleaning efficiency is strongly relates to flying velocity of cleaning liquid particles commonly in both system, there is different characteristic specific to each atomizing structure.

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Semi-conductor lithograph machine have to be kept away from many kind of vibration, one of which is floor vibration, the isolation performance from floor to body vibrations is particularly called the transmissibility. Isolation vibration system is very important unit of lithograph machine for semi-conductor manufacturing. In recent years, the progress of semi-conductor is remarkable development, therefore outside vibration isolation performance became more important factor than current machine for total machine accuracy. Isolation vibration system is generally supported by air-spring, and isolated the main body from unnecessary vibration from outside, mainly from floor vibration. There is one of mechanical method in order to increase vibration rejection ratio, which is reduced the stiffness of air-spring by using auxiliary tank. Helmholtz resonance is caused by using auxiliary tank, and vibration rejection ratio become worse. In usual, as introduced in the Handbook, we can reduce the peak of Helmholtz-resonance by adjusting the aperture with the built-in the connected pipe. Furthermore, there is the best aperture as introduced in the Handbook. However there is no reference regarding the relationship between Helmholtz frequency and vibration rejection ratio. This paper firstly explains by analysis that there is no effect of auxiliary tank over Helmholtz frequency and over-damping for Helmholtz lead to no effect, it will prove there exist the optimization of damping in the end. Next, this shows experimental result, such as pressure response in the air-tank and vibration rejection ratio by using sintered metal as damping device.

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The purpose of this research is to develop a virtual ergonomic assessment system that evaluates grasp stability and ease of grasping of products such as digital cameras without real subjects and physical mockups by integrating 3D digital hand models with the 3D CAD models of the products. In this paper, we propose “ease of grasping” as a new index for the assessment. This index is calculated from the “EOG-map”, in which example grasp postures of real subjects are plotted as principal component scores in low dimensional space. We also propose an optimization-based correction method for an inappropriate finger posture by using the EOG-map.

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Recently scanned meshes from mechanical objects can be easily acquired using high-energy industrial X-ray CT scanning technologies, and these meshes are widely used in various fields of product developments. Mechanical objects often exhibit symmetries for their functionality. They are originally defined by creating a copy of the solid and then by placing it with a certain transformation including an arbitrary set of translations, rotations, and reflections. Therefore it is desired to detect such symmetries from the scanned meshes for their effective use in mesh applications, such as reconstruction of CAD models with compact data representations or CAE mesh enhancement using the symmetries. In this paper, we propose a method that can detects multiple Euclidean symmetries from scanned meshes of mechanical objects based on a combination of ICP and region growing algorithms. We define Euclidean symmetries detection as to detect both pairs of regions that match under certain transformations and their transformations including arbitrary sets of translations, rotations, and reflections. We also propose a method that derives all possible sequences for reconstructing an entire model from the original mesh using planar-reflective symmetries among all the detected symmetries, and represents them in an AND/OR graph in order to compactly represent the mesh. Our proposed method contains several advantages. It can robustly detect symmetries from noisy scanned meshes that include many planar regions. Our method also can detect both global and local Euclidean symmetries from meshes. Moreover it can detect maximally large pairs of regions under user specified tolerances. We demonstrate the effectiveness of the proposed method from various experiments using X-ray CT scanned meshes of mechanical objects.

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The acceleration sensors as vibration sensors are widely used in the field of vibration control. In order to derive the displacement signal from the acceleration sensor, the second order integration is required. Then, the velocity sensor is convenient for vibration control, because the displacement signal can be easily derived. Furthermore, an absolute displacement sensor is more convenient since the triple signals i.e. acceleration, velocity, and displacement signals can be simultaneously utilized. In this paper, a model of the spurious vibration due to the gravity compensated mechanical spring is firstly derived. Based on this modeling, high frequency characteristic is modified. Next the electrical damping loop is added to suppress resonant peak in the low frequency region. Finally, a frequency shaped displacement sensor is applied to the air-spring type anti-vibration apparatus with voice coil motor. It is shown that the mechanical impedance can be manipulated.

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