To reduce the intra-pair skew for a differential transmission copper cable, we performed a time response analysis of the transmission characteristics. The results of this analysis clarified that the intra-pair skew is determined by the product of three factors, namely, a parameter related to the imbalance of the differential pair, the amplitude ratio of the common-mode to the differential-mode, and the propagation time difference between the common-mode and the differential-mode. In the analysis of a new cable structure which has one batch extruded insulator covering two wires, it has been confirmed that the propagation time difference is very small, and the intra-pair skew hardly increases even if the imbalance becomes worse. Measuring the characteristics of the cable produced in a trial manufacturing run showed intra-pair skew distributions of 11.5 ps/m with the conventional structure and 6.2 ps/m with the new structure.

In order to stably operate electronic equipment in environments where sulfide-corrosion-induced failures occur, we investigated the effectiveness of a coating process as a countermeasure against the corrosion of electronic components mounted on printed circuit boards. We have clarified that the sulfide corrosion behavior of coated electronic components with conformal coating is dependent on the transmission of reduced sulfur. Further, we established a new gas transmission test method and a sulfide corrosion life estimation method. The sulfide corrosion lifetime of a chip resistor with high sulfide corrosivity was estimated using the diffusion coefficient and the solubility coefficient of the conformal coating calculated using the gas transmission test. Based on the estimate of the sulfide corrosion lifetime, we have created an anticorrosive design diagram to determine the coating thickness needed to satisfy the design life target.

In this paper, the phenomena occurring inside the piezo inkjet, which is often used in printable electronics, are divided into "linear phenomena" and "non-linear phenomena". We found that the operating region is usually linear, but in some cases it can be non-linear. After clarifying this, we obtained a calculation result that matches the actual measurement result of the ejection velocity by a method of incorporating the nonlinear phenomenon into the equivalent circuit using element modeling. As a result, we have succeeded in proposing for the first time the possibility that the non-linear phenomenon inside the inkjet is caused by a quadratic functional increase accompanied by oscillation of the acoustic resistance with respect to the flow near the orifice.

The authors studied particle removal technology for semiconductor chips. Particles on semiconductor chips have been an obstacle to the practical use of direct bonding for chip level. The particles are mainly silicon-based dicing dust and organic matter.

Concretely, we have developed a new particle-removal technology using hydrogenated ultrapure water and a wiping process.

Due to the demand for high-speed performance, 2.n/3D packaging is being developed. Silicon interposer plays an important role in 3D packaging. However, it is not widely used because of its high cost. Therefore, attention has been paid to using glass as a base material instead of silicon.

We have developed a metal oxide adhesion layer that enables wet chemical Cu metallization on glass. The adhesion layer is formed as a smooth and ultra-thin film (about 5–10 nm) by dip-coating. In addition, it has high peel strength of 4 N/cm or more and enables fine line formation (L/S = 9/9 μm), uniform conformal plating, and filling plating. Therefore, this process shows potential for use with glass interposer and glass substrate.