Polybenzoxazoles (PBO) precursors consisting of bis (3-hydroxy-4-amino) biphenyl (p-HAB), 2, 2'-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (AH6FP), and terephthaloyl choloride (TPC) showed high solubility in common organic solvents. PBO precursors were polymerized from silylated p-HAB (50mol-%), AH6FP (50mol-%), and TPC (100mol-%), in NMP containing LiCl (about 1 wt-%) . The PBO precursor was precipitated in a large excess of water to remove some ionic impurities and to refine it. The concentration of the chlorine ion in the PBO precursors analyzed by ion chromatography was about 500 ppm, after the precipitate was repeatedly washed with fresh water. The corrosion of copper or silver metals was significantly suppressed.

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To achieve nickel bumps with a high aspect ratio, anisotropic deposition is required in order to control the shape of the micro-bumps from flat to round. Flat bumps were obtained using a nickel sulfamate bath without additives. With the addition of pyridinium propylsulfonate (PPS) to the nickel sulfamate bath, however, the bumps became round. Cathodic polarization of the plating bath with PPS showed that PPS has an inhibiting effect on the deposition reaction. Moreover, the nickel deposition reaction was affected by agitating the plating solution in the PPS bath. Anisotropic deposition was accomplished by agitation from the side of the sample. It is assumed that the PPS is preferentially adsorbed on the edge of bumps under the effect of agitation which affects the bump shape. Therefore, the PPS suppressed deposition growth in the horizontal direction.

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High-K inorganic/organic composite materials for the interlayer insulation material of capacitors, which can be used for next generation high density packages, have been developed. The high volume loading of the below sub-micron diameter BaTiO₃ to the epoxy resin was studied to achieve high permittivity. 79 vol% filler loading was attained by improving the dispersion of the BaTiO₃ filler through surface treatment and controlling the particle size, which showed a relative permittivity of 130 at 1 MHz with 10 μm thick film. The relative permittivity in the RF region was also evaluated at higher than 100. The mechanical property, the temperature dependence of dielectric property, and the laser drilling process were also investigated.

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Lead-free solders are promising alternatives to conventional solders for environmental reasons.However, the range of temperatures which allow the solders to melt without damaging components is narrow. In order to improve quality and reduce the development period, we have developed a reflow analysis system utilizing experiment and simulation.

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