For the ECU that controls an electronic fuel injection system, we applied a card edge connector, which is a consumer electronics technology, and the transfer molding technology generally using a semiconductor manufacturing method. In the developed ECU, and the entire printed circuit board except the edge connector terminals was sealed with a specialized epoxy resin. This was the practical use of the world's first waterproof structure in the ECU alone. In addition, we have developed a waterproof card edge connector that mates with this ECU. A new insertion mechanism, multiple contact terminals, and the printed circuit board with little strength change were used, satisfying the durability requirements for motorcycles. These technologies, applied to the ECU, have achieved more than five times the productivity and 20% cost reduction compared to the conventional type. The developed product has been put into practical use for small motorcycles since the 2018 model.

FOWLP (Fan-out Wafer Level Package) is suitable for wireless mobile devices and automotive sensor applications due to their high performance and low cost. LMC (Liquid Molding Compound) has been applied to FOWLP production using a compression molding process. There are FOWLP technology trends such as large area molding, thin packages without grinding, multi-die packages including passive components and PoP (Package on Package). In the next generation, LMC requires severe warpage control and high flowability with fine filler. In this paper, we describe a LMC we developed which has high reactivity, fine filler size, and high reliability meeting the latest FOWLP requirements.

Adhesive joints are widely used in semiconductor packaging because of their light weight, low price, and high productivity. A recent study showed that the adhesive strength can be expressed as a constant value of the intensity of the singular stress field (ISSF) appearing at the interface end. However, since adhesive structures have complex three-dimensional geometries, it is necessary to find out where the debonding starts in relation to the ISSF to ensure product reliability. In this study, therefore, fundamental prismatic butt joint specimens are investigated considering the ISSF distribution along the interface circumference. It is found that most of the debonding starts from a point on the interface side except the interface corner where the peak ISSF appears in a limited region.

We evaluated the electrochemical behaviors and reliability of printed Silver (Ag) electrodes prepared from nanoparticle inks with the use of protective self-assembled monolayers (SAMs) under electronic bias conditions. The printed Ag electrodes were fabricated by inkjet printing on a hydrophobic substrate. The SAMs, which acted as barriers to moisture, were prepared by immersing the substrate in a pentafluorobenzenethiol (PFBT) solution under ambient temperatures. In this study, we investigated the electrochemical migration phenomenon using water drop testing, and the results showed that the formation of dendrites connecting the cathode and the anode, which can affect the electrochemical reliability of an electric device, was suppressed in the presence of the SAMs. The time before short circuit occurred was found to depend on the spacing between the electrodes. It was 130 s when the distance between the electrodes was 200 μm in the presence of a SAM. We demonstrated that Ag electrodes treated using the procedure described in this work show significantly fewer electrical short circuits caused by Ag dendrite formation, so that their electrochemical properties are substantially improved.

In this study, through the reaction of low-polarity, long-chain aliphatic diamine derived from biomass with 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide (BMI), we were able to acquire modified BMI (m-BMI) resins. Additionally, we were able to confirm the basic characteristics included in the low-induction trait of the cured resin. Furthermore, the low-polarity blended resin of p,p'-Divinyl-1,2-diphenylethan(BVPE), 1,2,4-Trivinylcyclohexane (TVCH), and modified BMI (m-BMI) produced modified BMI (m-BMI), which improved the low glass-transition temperature. By reducing the disadvantages of modified BMI (m-BMI) as well as imparting low dielectric and high heat resistance properties to the cured resin, we confirmed the performance required of polymer materials for mounting 5G communication-related electronics.

In conventional near electromagnetic field measurements, there is a problem where a primary noise source cannot be separately identified from candidates of noise sources operating at the same frequency. Therefore, we propose a method to identify the offending wiring by comparing the change in the radiated noise using a notch filter subject to a differential pair pattern. In the experiment, the effectiveness was confirmed for even-order harmonic wave noise, but it was not effective for odd low-order harmonic wave noise. This report examines the reason for the ineffectiveness and demonstrates additional experiments.

Experimental results show that implementing common-mode countermeasures in printed wiring is important in order to identify odd low-order harmonic wave noise using the proposed method.

This paper first discusses a design for a compact resonator using a Composite Right/Left-Handed Transmission Line (CRLH-TL). Moreover, an All-resonator type diplexer using proposed resonators is designed and fabricated. The measured frequency characteristics for the fabricated diplexer are mostly in agreement with an electromagnetic (EM) simulated one. The size of the measured diplexer is 6.3 mm × 4.35 mm (0.068λ_g × 0.047λ_g), which is much smaller than other compact diplexers.