We examined bottom-up via-filling by copper electrodeposition using a single diallylamine-type copolymer. We synthesized and used four new diallylamine compounds with modified side chains to further study the function of these compounds. We observed the vias cross sections, performed an electrochemical analysis and conducted quartz crystal microbalance (QCM) measurements. Moreover, we examined an adsorption model of the diallylamine-type compounds.

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Nickel/gold electroless plating is commonly used for surface finishing of printed wiring board due to its environmental stability and good solder wettability. However, since the gold deposition of electroless gold plating is a substitution reaction, local corrosion of nickel surfaces sometimes occurs which decreases the joining reliability of solders or wire bonding.
In this study, we focused on the internal stress of the nickel-plating layer. Gold electroless plating was performed on nickel plating with different internal stress levels, and the local corrosion behavior and shear strength of solder balls were investigated. Our results clearly show that the tensile strength of the nickel layer increases the occurrence of local corrosion and accordingly results in the deterioration of the solder joining strength.

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In this article, image-processing methods to extract thin stains on the surface of industrial products are described. When an image background is noisy, as with satin finished surfaces, it is difficult to extract stains exclusively. In this article, Fourier transform image processing methods to accomplish extraction of thin stains are presented. A low frequency transmitting filter, which has normal distribution transmission characteristics, was applied on a Fourier-transformed plane. Then, experiment to extracted thin stains on satin finished surfaces was performed by changing the bandwidth of the filter. The experiment produced good reconstructed images. It is shown that the light and dark distribution of the images corresponds appropriately to the frequency characteristics of the applied filter.
A torus frequency-transmitting filter to extract thin stains is proposed. Experiment is performed by changing the bandwidth of the torus filter. The torus filter demonstrated the ability to extract thin stains over a range of sizes which correspond to the frequency characteristics of the applied torus filter.

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Recent advances in downsizing inverters have made it necessary to reduce the surge voltage which can cause trouble in a high-speed power semiconductor that generates a square-wave electric current. Reduction of the wiring inductance between the capacitor and the power module was necessary to reduce the surge voltage. We developed a low-inductance layout technique where an eddy current flows through the cooling plate efficiently using a loop layout for the wiring of the power module. The magnetic flux of the eddy current reduces the wiring inductance by countering the magnetic flux of the wiring. We confirmed that approximately 0.11 times at 1 MHz of the square-wave electric current could reduce the wiring inductance of the trial manufacture power module.

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