Transient liquid-phase infiltration bonding is a new die attach process that uses capillary pressure as the driving force to infiltrate molten metal into a porous insert layer. Porous copper and silver materials fabricated by powder metallurgy have an open-cell structure, and it was clarified that the Sn alloy infiltrates into the pores of the porous materials by capillary action. When porous silver was used as an insert layer, a single phase Ag₃Sn bonding layer was obtained by the reaction of infiltrated molten Sn and solid phase Ag. On the other hand, when porous copper was used as the insert layer, a bonding layer with a multiphase structure of Cu and Cu-Sn IMCs was obtained. Cu-Sn IMCs were formed at the interface between the bonding layer and the base metal. In both cases, high shear strengths of more than 35 MPa were obtained. Further studies are needed to optimize the structure of the porous body and to clarify the infiltration phenomena associated with solid-liquid reactions.

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 Low-melting temperature Sn-Bi solder alloys have attracted a lot of attention. The use of low-temperature soldering also reduces the energy costs of manufacturing processes. It enables the production of low-cost assembly materials, such as printed circuit boards, without high temperature resistance, and temperature-sensitive components, such as LEDs, by avoiding thermal damage. In Sn-Bi solder alloy, the disadvantage of brittleness has prevented its wide practical application. In order to promote the better application of Sn-Bi-based solders, many efforts have been made to improve the mechanical properties and reliability of Sn-Bi-based solders. However, the superplasticity mechanism of Sn-Bi-based solder alloys has not been established. Therefore, this study presents some results of the author’s research, tensile behavior and measurement of strain rate sensitivity indices of Sn-Bi-Cu, Sn-Bi-Ni, Sn-Bi-Zn, and Sn-Bi-Sb alloys.

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 The movement towards carbon neutrality (CN) is accelerating globally. In the manufacturing industry, we are developing energysaving products and services that lead to the reduction of greenhouse gas (GHG) emissions, as well as promoting the production of energy-saving products. SiC power semiconductors, which are one of the energy-saving products, use Ag sintered materials that require high-temperature firing in the die bond part to improve product performance. In order to derive the properties of Ag sintered materials governed by sintering shrinkage, understanding the behavior of sintering shrinkage and its mechanisms is necessary for material and process optimization. In addition, to promote energy saving in the manufacturing process, it is also necessary to have the technology to appropriately design the heat treatment conditions based on the sintering mechanism. In this paper, we introduce the measurement of the sintering shrinkage behavior that governs the characteristics of Ag sintered bonding, t

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 As the practical application of 3D heterogeneous chip integration progresses rapidly, the demand for Chip-on-Wafer (CoW) bonding is increasing. This paper examines recent research trends in CoW bonding and discusses current technologies and associated issues. In addition, this paper introduces the authors’ three core technologies for narrower pitch bonding. First key technology is a method to quantify the thermal fluctuation behavior in thermal compression bonding. The second is a new cutting-edge micro bump formulation process using a combination of thermal imprinting and photolithography. The third is a in-situ determination system of the quality of micro-bump bonding process using the 2-axis micro strain sensors embedded in the chip.

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 This study aimed to investigate the formation of three-dimensional structural films by plating and dealloying from a Cu-Ni alloy plating solution by controlling potential. Additionally, the adhesion of bisphenol A epoxy resin to the three-dimensional structural films was evaluated. Following the adhesion test, the fracture surfaces were observed and the failure modes were analyzed to evaluate the effect of the formation conditions of the three-dimensional structural films on the adhesive strength. From the surface observation, the film formed by plating under －1.0 V potential was found to form spherical structures with a maximum diameter of 10 μm on the surface. Furthermore, the film formed by dealloying under +0.5 V potential was found to form pores with a maximum diameter of 2 μm at the top of the three-dimensional structures. Cross-sectional observation of the joints revealed that the epoxy resin filled the spaces between the three-dimensional structures, while no filling of the pores formed by dealloying was observed. The shear test of the joints showed that the joints with three-dimensional structural films formed under the conditions of －1.0 V and －1.5 V potentials exhibited high shear strength. It was found that the joints fractured at the interface between the three-dimensional structural film and Cu plate by observing the fracture surface after the shear test.

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