Research of Wafer Level Bonding Process Based on Cu–Sn Eutectic

In 3D-system packaging technologies, eutectic bonding is the key technology of multilayer chip stacking and vertical interconnection. Optimized from the aspects of the thickness of the electroplated metal layer, the pretreatment of the wafer surface removes the oxide layer, the mutual alignment between the wafers, the temperature of the wafer bonding, the uniformity of pressure and the deviation of the bonding process. Under the pretreatment conditions of plasma treatment and citric acid cleaning, no oxide layer was obtained on the metal surface. Cu/Sn bumps bonded under the condition of 0.135 Mpa, temperature of 280 °C, Sn thickness of 3–4 μm and a Cu-thickness of five micrometers. Bonded push crystal strength ≥18 kg/cm2, the average contact resistance of the bonding interface is about 3.35 mΩ, and the bonding yield is 100%. All performance indicators meet and exceed the industry standards.

Lighting System Packaging for Smart Underwater Reefs for Sensing, Communications, and Robotics

Strings and ropes are a proven, common fisheries and aquaculture construction elements outside the US. Using them as scaffolding also enables a diversity of ocean sensing, communications and architectures, including our goal of sentinel reefs. Packaging of electronics is key to enabling such structures and systems. Our research is towards a demonstrable science-engineering-informed framework for 3D habitat designs critical to stock fish development & coastal protection. These ‘nature-inspired’ reef infrastructures, can enable novel instrumented ‘reef observatories’ capable of collecting real-time ecosystem data. Embedding lighting and electronic elements into reef systems are the first systems in development. This new approach of bringing light to the underwater world for optical sensing, communication and even a new breed of underwater robotic vehicle is an interdisciplinary research activity which integrates principles of electronic packaging, and STEM with art/design.

Design of temperature-immunization system packaging for the resonant pressure sensor

Based on the study of the material matching and structure cooperating, this paper mainly explores a new packaging structure with low thermal mismatches which can enhance the accuracy and stability of the resonant pressure sensor. According to the finite element simulation, the rule of the coefficient of thermal expansion (CTE) and the depth of the groove on the substrate, which has an influence on the temperature sensitivity, could be obtained. By analyzing the effect of temperature on the resonant frequency, it shows the temperature sensitivity of the new packaging structure is −0.97 Hz/[Formula: see text]C in 20 kPa, under the temperature range of 30[Formula: see text]C to 80[Formula: see text]C. After analyzing resonant frequency stability at different temperatures, it is found that the time for achieving stability at different temperatures of the new packaging structure is at least 10 min less than that of TO packaging structure. The average frequency’s relative variation ratio of the new packaging structure at different temperatures remains roughly the same, and the variation range is within ±[Formula: see text]0.005% as time changes. These results indicate that the new packaging structure has the characteristic of great temperature-immunization.