Recently, the demand for the miniaturization of printed circuit boards has been increasing, as electronic devices have been sharply downsized. Conventional multi-layered PCBs are limited in terms their use with higher packaging densities. Therefore, a build-up process has been adopted as a new multi-layered PCB manufacturing process. In this process, via-holes are used to connect each conductive layer. After the connection of the interlayers created by electro copper plating, the via-holes are filled with a conductive paste. In this study, a desmear treatment, electroless plating and electroplating were carried out to investigate the optimum processing conditions for Cu via filling on a PCB. The desmear treatment involved swelling, etching, reduction, and an acid dip. A seed layer was formed on the via surface by electroless Cu plating. For Cu via filling, the electroplating of Cu from an acid sulfate bath containing typical additives such as PEG(polyethylene glycol), chloride ions, bis-(3-sodiumsulfopropyl disulfide) (SPS), and Janus Green B(JGB) was carried out. The desmear treatment clearly removes laser drilling residue and improves the surface roughness, which is necessary to ensure good adhesion of the Cu. A homogeneous and thick Cu seed layer was deposited on the samples after the desmear treatment. The 2,2'-Dipyridyl additive significantly improves the seed layer quality. SPS, PEG, and JGB additives are necessary to ensure defect-free bottom-up super filling.

Carbon material shows relatively high strength at high temperature in vacuum atmosphere and can be easily removed as CO or gas in oxidation atmosphere. Using these characteristics, we have investigated the applicability of carbon mold for precision casting of high melting point metal such as nickel. Disc shape carbon mold with cylindrical pores was prepared and Ni-base super alloy (CM247LC) was used as casting material. The effects of electroless Nickel plating on wettability and cast parameters such as temperature and pressure on castability were investigated. Furthermore, the proper condition for removal of carbon mold by evaporation in oxidation atmosphere was also examined. The SEM observation of the interface between carbon mold and casting materials (CM247LC), which was infiltrated at temperature up to , revealed that there was no particular product at the interface. Carbon mold was effectively eliminated by exposure in oxygen rich atmosphere at for 3 hours and oxidation of casting materials was restrained during raising and lowering the temperature by using inert gas. It means that the carbon can be applicable to precision casting as mold material.

Electrochemical deposition characteristics of CdSe nanorods were investigated for hybrid solar cell applications. CdSe nanorods were fabricated by electrochemical method in CdSO4 and H2SeO3 dissolved aqueous solution using an anodic aluminum oxide (AAO) template. Uniformity of CdSe nanorods was dependent on the diameter and the height of holes in AAO. The current density, current mode, bath composition and temperature were controlled to obtain a 1:1 atomic composition of CdSe. CdSe nanorods deposited by direct-current method showed better uniformity compared to those deposited by purse-current and/or purse-reverse current methods due to the bottom-up filling characteristics. H2SeO3 concentration showed more significant effects on pH of solution and stoichiometry of deposits compared to that of CdSO4. A 1:1 stoichiometry of uniform CdSe nanorods was obtained from 0.25M CdSO4-5 mM H2SeO3 electrolytes with a direct current of 10 mA/cm2 at room temperature. X-ray diffraction and electron diffraction pattern investigations demonstrate that CdSe nanorods are a uniform cubic CdSe crystal.