Intrabody communication uses the human body as the transmission medium. The authors have created a simplified signal transmission model to simulate the intrabody propagation mechanism in the frequency region below several tens of MHz. Considering the human body as a highly conductive insulator, the authors applied the power feeding mechanism of the linear antenna as the intrabody propagation mechanism. To test the validity of the model, the authors investigated transmission gains using a 10.7-MHz sine-wave transmitter and receiver that were fabricated for this purpose. First, the authors changed the number of electrodes attached to the transmitter and receiver and found that the optimum electrode number is 2 for the transmitter and 1 for the receiver. Then, the dependence of transmission gain on the difference between transmission direction and electrode position and on the existence of clothing was investigated. All of these results could be explained with the proposed model.

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In this study, EMI caused by ground bounce was evaluated by a numerical simulation at FM bands (76 MHz-108 MHz) . The numerical simulation was implemented using 3-D Method of Moments (3-D MoM) with an LSI power current model. We quantitatively investigated the process of LSI power current models and determined how to apply them to 3-D MoM. Far electric field intensity was calculated by 3-D MoM for two kinds of printed wiring boards (before EMI suppression, after EMI suppression) . EMI suppression was accomplished by changing the bypass capacitor value and the trace shape of the power supply. Finally, the results of our simulation were verified experimentally.

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To achieve a thin electronics package with a thickness of 300μm or less, a new tape substrate and a package manufacturing process that uses peelable copper foil were designed and constructed. The new method has some interesting characteristics; for example, the electrical terminal patterns are formed with plating instead of etching the copper foil, and the remaining copper foil is dissolved after the peelable tape base is removed. After some investigation we succeeded in constructing a 250μm thick LGA package a 40% thickness downsizing from the thickness of conventional QFN packages. In this trial, we determined a suitable electrical terminal structure for the package, 0.3μm or more gold and 3μm nickel. The package has repetition seven times durability in the solder reflow examination under JEDEC MSL 1 conditions, and has passed 800 cycles in a temperature cycling test. In addition, this new method does not require a large investment for manufacturing the package.

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Conventionally, IC packaging uses spot-silver plating, die-bonding, wire-bonding and resin molding on copper lead frame materials, along with solder plating of the lead parts to be soldered onto a printed board. This conventional method, however, has some serious problems that need to be addressed, such as Pb in the solder plating. Consequently, Pd-PPF has received attention for both environmental and technical reasons and has been practically applied in lead frame packages. Environmentally, it is Pb-free and the cyan consumption is reduced by the elimination of silver plating, which consumes large amounts of cyan. A number of technical benefits also can be achieved, in addition to the environmental improvement. Currently, it is important to make the Pd-PPF plating thinner, both to improve its properties and to reduce costs in the face of soaring precious metal prices. Thus, a crystalline adjuster was added to a palladium plating solution with a view to improving film quality and solder wettability was examined in order to improve the high-temperature resistance of palladium plated film. With the new additive, solder wettability was dramatically improved, and good solder wettability was obtained even from a thinner Pd-film. Moreover, other properties proved to be equivalent to or better than those achieved with the conventional process.

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Screen printing is the method most commonly used to fabricate various electronic components. Generally, the stencil for screen printing is formed with a woven mesh of thin stainless steel wires. However, electronic components are becoming increasingly miniaturized, and it is difficult to use such a stencil for finer applications. In this study, electroformed Ni-Co alloy meshes for screen printing were developed for these finer applications. The tensile properties of the mesh materials and printing durability of the meshes were investigated and compared with those of a conventional woven stainless steel mesh.

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