The increasingly severe demands of concurrently increasing die size while reducing package size have made the mechanical stability of IC packaging technologies a grave concern. The dominant failure is caused at the interface between dissimilar materials. To investigate the effect of polyimide surface morphology and chemistry on the epoxy molding compound adhesion, the polyimide samples were characterized with X-ray photo emission spectroscopy (XPS), atomic force microscopy (AFM), attenuated total reflection (ATR), interfacial adhesion tests. The results of the characterization and an explanation of the primary factors affecting interfacial adhesion are presented in this paper.

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Optical interconnection that replaces conventional metal wirings with optical ones is one of the most promising ways for overcoming the problem of EMI (Electromagnetic Interference) . A polymeric optical waveguide is a key device of optical wirings. We prepared several optical waveguides having various structures and measured optical EMI from the waveguides experimentally. Simulation study about the optical EMI was also done using BPM (Beam Propagation Method) . It was found that optical EMI could be suppressed enough when the over-cladding layer thickness was large and the excited optical mode and the waveguide eigenmode were well matched.

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Recently, the underfill mount structure is noticed. However, the sufficient thermal fatigue reliability evaluation has not been established. In this study, the authors proposed a simple reliability evaluation method using Finite Element Analysis (FEA) . In addition, an approximate calculating method for the reliability evaluation parameter (Total equivalent inelastic strain range) was developed using Statistical Design Support System (SDSS) .

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About Sn base solder, it is paid attention as solder which does not contain Pb, I investigate mechanical and thermal fatigue properties of Sn-Ag series solder, Sn-Sb series solder and Sn-Ti series solder systematically. As the result of experiments, Sn-Ag series solder and Sn-Sb series solder have a good mechanical and thermal fatigue properties, they have from 1.4 to 1.8 times longevity as long as Sn-37Pb solder. Moreover, Sn-Ag series solder reinforced by extraction is excellent longevity characteristic to Sn-Sb series solder reinforced by dissolution and it is proved that the longevity characteristic expanded by adding Ag, Sb, Bi. But Sn-Ti series solder has poor mechanical and thermal fatigue property, it was proved not to be able to use it as a solder joint. Sn-Ag and Sn-Sb series solder are the most suitable material as the substitute of Sn-37Pb solder.

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In recent years, problems have been arisen such as failure between conductors on printedcircuit board caused by ionic migration due to the high-density surface mounting of electric equipment and the popularization of portable equipment. Ionic migration occurs under the influence of an applied electric field, when water adheres to the site conductive patterns such as solder, copper, or silver. To investigate this phenomenon, new measurement method was developed by the authors, which enables in situ monitoring of migration process by quartz crystal microbalance (QCM) . As a result, the amount of anodic deposition and cathodic deposition, which influence migration growth, is smaller for lead-free solder than that for lead solder. The deposit on the cathode of lead solder was lead and that of lead-free solder was tin. Tin easily generates the oxide film compared with lead. Lead-free solder whose principal ingredient is tin formed the oxide film on anode electrode. And the anodic dissolution was controlled. Therefore, it is thought that the migration growth of lead-free solder is slower than that of lead solder. When the material which destroys the oxide film like flux exists, the migration growth is especially fast or even in the tin-zinc solder.

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Role of via-filling additives for Copper electrodeposition is discussed. Addition of Cl^- causes macro steps. PEG forms about 10nm granular molecules and absorbs preferentially on the edge of these macro steps. This adsorption of PEG inhibits the macro step growth. About 10nm fine copper crystals form with an addition of JGB and SPS. With an addition of Cl^-and PEG, the current-overpotential curves shift towards to the cathode side, which inhibits copper electrodeposition. With JGB in addition to Cl^-and PEG, the curve shift towards to the cathode side with an increase in rotation speed of rotating disk electrode. This means that PEG molecules become diffusion control with JGB. We observe less adsorption of PEG molecules at via bottom if compared to that at via outside. PEG adsorption inhibits copper electrodeposition at via outside and preferentially fill the via bottom.

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We developed the WLBI technology that was applicable to Al pads wafer. Contact stabilization between Al pads and bumps was one of important subjects for developing WLBI probe. One problem was the high contact resistance for a while after making contact at room temperature, and another problem was the increase of the contact resistance during high temperature (125°C) . In this paper, we report that we analyzed those problems and that those problems were solved by making the bumps surface ruggedness and applying suitable materials to the bumps surface.

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Pb-free electronic devices have been developed to remove the environmental damage from the human body. This report is related to the heat resistance and the joint reliability of diebonded section with Sn-15Sb solder. A solder bath dipping test for 10 seconds above 250°C leads to the void genelation into Sn-15Sb solder, which tends to increase the thermal resistance with a short time of thermal fatigue test. Furthermore, it should be selected the diebond solder and the back metal of die to keep the solidus temperature of die-bonded section. For the practical reflow soldering of semiconductor devices having Sn-15Sb die-bonded solder, it is essential to propose the reflow profile with the maximum peak temperature below 240°C.

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