Nobutake Tsuyuno

Corrosion studies of copper and aluminum interconnects exposed to automotive oils

Applications in the automotive field present some of the harshest environments for electrical components, especially for plastic packaging devices. Encapsulation technology by epoxy molding compounds is widely used for integrated circuit and large-scale integration packaging. It is not a hermetic sealing method, but it provides small sized and very low cost packaging. When used for on-engine or in-transmission modules, long-term reliability becomes a concern. This paper examines the reliability of epoxy encapsulated electronic devices in harsh environments, such as in high temperature automotive oil and oil vapor environments. The focus is on wiring corrosion in electronic devices, taking into account these mounted in an automatic transmission of a car. Corrosive substances from high temperature oil and corrosion behavior of metals are analyzed. A novel test method is introduced, which can evaluate the corrosive level under various durability conditions.

Investigation of thermal management method for coil and capacitor in automobile ECU

When using a thermal sheet for cooling, heat-generating components are pressed strongly against the thermal sheet to maximize the contact area and reduce the thermal sheet thickness. However, such pressure can reduce the reliability of the solder joints on a printed circuit board. In this study, a novel heat dissipation method of achieving enhanced heat dissipation without the need for applying pressure was investigated. In this method, electrolytic capacitors and electric coils are immersed into an uncured thermal gel. The gel is then cured and adsorbed to the heat-generating components even if they have complex shapes. As a result of comparing the conventional method and the proposed method, the effectiveness of the proposed method was confirmed.