Many kinds of oxide compounds, consisting of various chemical elements in different composition ratios, have been created and their physical and electrical properties have been studied. The results of the present study indicate that oxide based systems such as tin, vanadium, and niobium oxide based systems exhibit switching, oscillating, and gas detecting phenomena, which are of special interest to us. Especially, tin oxide based systems exhibit gas detecting and switching effects, vanadium oxide based systems exhibit switching and oscillating effects and niobium oxide based systems exhibit non-volatile memorizing, oscillating, and switching effects.

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The etching rate of copper in CuCl₂-HCl solution was investigated by using agitated vessel. It was revealed that this system was controlled by mass-transfer. The dissolution rate of CuCl was almost double the etching rate of copper except for low CuCl₂ concentration region. Considering a stoichiometric relationship, it was thought that CuCl was precipitated on the copper surface during wet etching and the etching rate was controlled by the diffusion rate of CuCl₂^-. The etching rate could be evaluated by the diffusion rate of CuCl₂^- that was obtained from the saturation concentration and the diffusion coefficient. In the low CuCl₂ concentration region, the etching rate was calculated by using the mass transfer model that considered not only molecular diffusion but also electronic migration of ionic species. In results, the calculated values were in good agreement with the observed ones.

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Electronics products are becoming smaller these days. The connection technology with fine pitch electrodes are very important. We already developed the new method for connecting FPC (Flexible Printed Circuit) and PWB (Printed Wiring Board) . In the new method the volume expansion energy of alkane boiling was used instead of flux. There were no detectable insulation deterioration between the fine pitch electrodes. This paper presented the simultaneous adhesion and encapsulation technology at alkane soldering. When alkane was spread on PWB, and PEI (Poly Ether Imide) FPC was heated by heating tool on the PWB, the adhesion, encapsulation and soldering simultaneously was completed.

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In the flip-chip packages using Anisotropic Conductive Paste, the load, which remain in the interface between Cu pad and Au bump after manufacturing process, keeps contact resistance stable. According to the resin properties or bonding (B'g) load, the contact resistance may be high and unstable in the reliability test such as high temperature and high humid tests. In this paper, in order to assess the bonding margin, the stress simulation through B'g process was carried out after the evaluation of resin properties. Then, the compressive load, which exists in the interface between Au bump and Cu pad, was generated. Using the results of stress simulation, the B'g margin was evaluated by comparing with the experimental results of the relationship between B'g load and contact resistance after B'g process. Furthermore, using response surface methodology, considerations have been given to reveal the effect of various scatters such as material characteristics and manufacturing on the B'g margin.

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As an endocrine disrupting chemical, bisphenol-A has been paid much attention from the view point of environmental protection. Bisphenol-A has been used for producing polycarbonate and epoxy resins as their main constituent, and those are widely accepted as a substrate and package for semiconductor industries. Nowadays, it is important to analyze bisphenol-A which was leached from the organic materials used for electronic devices. In this study, the analysis was conducted with the procedure of Japan Society for Environmental Chemistry, and evaluated 4 kinds of PWBs (printed wiring boards), 2 kinds of mold resins, solder resists and insulation resins for build up substrates. To extract the bisphenol-A into water, samples were soaked in the water for 1 hour at 50°C or for 1 week at room temperature in the dark, and the amount of bisphenol-A was determined by gas chromatography/mass spectrometry (GC/MS) measurement. As a result of the analysis, it was found that the max. amount of bisphenol-A leached from a PWB sample was 212 ng/g. Furthermore, it was revealed that the analysis data showed big difference between the each materials, PWB, mold resins and solder resists. A PWB material which is not composed with epoxy material was detected no bisphe-nol-A as expected reasonably.

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Cu metal and low k materials have been proposed as metallization process to reduce RC delay of device. Electro plating was selected for the Cu metallization process due to its better gap-filling capability and lower cost. However, electoless plating is nominated for cap material deposition process since its plating results in selective deposition on metal. It is herein reported that Ni-B deposited by electroless plating can be suitable for cap material on Ag, which is nominated as metal after Cu. As a result, it has been confirmed that Ni-B by electrolesss plating with DMAB has the barrier effect against Ag, and has selectivity only on Ag with good deposition rates.

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Semiconductor package has been become more complex structure, including wiring technique. And, matter of wire sweep due to resin flow in encapsulation begins to be more complicated again. It first the distribution of wire sweep in QFP was investigated. Then, it was examined fundamentally about some kinds of influence on encapsulation conditions. And, computer simulation was done about that result. Furthermore, we studied on pressure inside cavity for the wire sweep.

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The continuing demand for Mobile Information Terminal Tools to become smaller and lighter requires for electronic parts inside these mobile tools to also become smaller and lighter. In today's electronics, the area of the substrate itself is shrinking in size as well as the surface area for chip parts to be assembled on. For this reason, fine-pitched high density IC assembly is being focused. But high-density assembly has its limits, and will soon be needing a new technology. This is where our TZ-CSP (Tape Z-axis Chip Size Package) comes in. We have developed a new packaging method of simply stacking the chips on each other (multiple layered in Z-axis direction) . The concept of the TZ-CSP was developed to have a wide variety of usage while being able to be assembled on reel to reel which enables high production yield and reduce costs. Although presently, we are working on multiple stacking with the same IC, our goal is to not only be able to stack same chips but also be able to stack a variety of ICs and chip parts into a single package.

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Polarization characteristics for electroless gold plating baths consisting of hydrazinium sulfate and sodium gold sulfite were investigated. Both anodic oxidation of a reducing agent and cathode reaction of gold ion were promoted by the bath temperature rise. Mixedpotential theory was materialized in this bath. And rise in bath temperature increased not only reduction rate but also substitution rate.

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The advantage of forming under barrier metal using the electroless plating method, compared to electro-plating method, is that the electroless plating method requires less process steps, which means less time will be required. Normally, when applying solder to electroless nickel plated surface in phosphoric acid bath, a fragile layer of enriched phosphorus is formed between the two metals. It is also a fact that this enriched phosphorus layer is easily destroyed by external stress such as thermal stress.In this paper, we have formed a solder bump (pad) onto the surface of the under barrier metal formed using the electroless nickel plating process, controlling the phosphorus density. As a result of analyzing the movements of the phosphorus density of the joining layers before and after the several acceleration tests, we were able to see a trend that by controlling the electroless nickel plating process, we are able to regulate the phosphorus within the plating layer.

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Copper electroplating is greatly interested in ULSI technology because of copper damascene process. We have already reported that void-free copper fill can be achieved by the selection of proper additives. However, inclusion of additives in copper deposit may cause deposit deterioration. A possibility of copper filling by the wave form control was examined using additive free bath. The void-free filling can be achieved by current density in stepwise current wave form by changing from lower to higher current.

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