With the rapid development of 5G, artificial intelligence (AI), and high-performance computing (HPC), there is a huge increase in the data exchanged between the processor and memory. However, the “storage wall” caused by the von Neumann architecture severely limits the computational performance of the system. To efficiently process such large amounts of data and break up the “storage wall”, it is necessary to develop processing-in-memory (PIM) technology. Chiplet combines processor cores and memory chips with advanced packaging technologies, such as 2.5D, 3 dimensions (3D), and fan-out packaging. This improves the quality and bandwidth of signal transmission and alleviates the “storage wall” problem. This paper reviews the Chiplet packaging technology that has achieved the function of PIM in recent years and analyzes some of its application results. First, the research status and development direction of PIM are presented and summarized. Second, the Chiplet packaging technologies that can realize the function of PIM are introduced, which are divided into 2.5D, 3D packaging, and fan-out packaging according to their physical form. Further, the form and characteristics of their implementation of PIM are summarized. Finally, this paper is concluded, and the future development of Chiplet in the field of PIM is discussed.

With the increasing number of inputs and outputs, and the decreasing interconnection spacing, electrical interconnection failures caused by electromigration (EM) have attracted more and more attention. The electromigration reliability and failure mechanism of complex components were studied in this paper. The failure mechanism and reliability of complex components during the electromigration process were studied through the simulation and the experiment, which can overcome the limitation of experimental measurement at a micro-scale. The simulation results indicated that the solder joint has obvious current crowding at the current inlet, which will significantly enhance the electromigration effect. Based on the atomic flux divergence method, the void formation of solder joints can be effectively predicted, and life prediction can be more accurate than Black’s equation. Experimental results indicated that the resistance of the daisy chain could be significantly increased with the process of void formation in the solder and corrosion of the leads. Moreover, the growth of intermetallic compounds can be obviously promoted under current stress. The main composition of the intermetallic compounds changes from almost entirely Cu₅Sn₆ to Cu₅Sn₆ and Cu₃Sn; the cracks can be detected at the Cu₃Sn layer. Specifically, the mean time to failure is 1065 h under 1.4 A current and 125 °C based on IPC-9701A guidelines.

In this paper, electrical characteristic analysis and corresponding experimental tests on gold bonding wire are presented. Firstly, according to EIA (Electronic Industries Association)/JEDEC97 standards, this paper establishes the electromagnetic structure model of gold bonding wire. The parameters, including flat length ratio, diameter, span and bonding height, were analyzed. In addition, the influence of three kinds of loops of bonding wire is discussed in relation to the S parameters. An equivalent circuit model of bonding wire is proposed. The effect of bonding wire on signal transmission was analyzed by eye diagram as well. Secondly, gold bonding wire design and measurement experiments were implemented based on radio frequency (RF) circuit theory analysis and test methods. Meanwhile, the original measurement data was compared with the simulation model data and the error was analyzed. At last, the data of five frequency points were processed to eliminate the fixture error as much as possible based on port embedding theory. The measurement results using port extension method were compared with the original measurement data and electromagnetic field simulation data, which proved the correctness of the simulation results and design rules.

The electronic devices suffer great vibration and temperature fluctuation in an airborne environment, which has been always a big challenge for reliability design. In this paper, the reliability of the complex electronic components for airborne applications under a thermal cycling test, random vibration and combined loading has been investigated by experiment tests and finite element simulation. The fatigue life and failure location under different loadings have been compared and discussed, respectively. The results indicated that the combined fatigue life was much shorter than a single-factor experiment. The failed solder joints mostly appeared at the interface between the solder and the copper pad on the component side and the location was at the corner for all three harsh environment tests. Nevertheless, several differences could be observed. For temperature cycling, all the specimens failed due to the increase in daisy chain resistance rather than the open circuit for the combined loading test. That is because the degeneration of the solder caused by temperature variation led to lower stress levels and fatigue life. Moreover, the pins fractured at the welding regions have been observed. The modified Coffin—Manson model, Miner’s linear fatigue damage criterion and Steinberg’s model and rapid life-prediction approach were used to predict the fatigue life under temperature cycling, random vibration and combined loading, respectively. With these methods, the accurate numerical models could be developed and validated by experiment results. Thanks to the simulation, the design time could be effectively shortened and the weak point could be determined.

Electric current pulse (ECP) was commonly applied to solidification process of Al melt to achieve fine solidification microstructure. In this paper, numerical simulation method was employed to analyse flow behaviour of the melt and the mechanism of ECP on the grain refinement during the solidification. The calculation results showed that the ECP led to fluctuation of the Al liquid surface, and the liquid flowed inward and down in a circular motion. The fluctuation and circular flow behaviour were caused by the forces including Lorentz force, surface tension and buoyancy. The results also revealed that the higher the frequency and peak value of the ECP, the larger the flow velocity was. On the other hand, the depth of the electrodes in the liquid had little influence on the convection flow of the liquid. In summary, our simulation results explained the refinement mechanism of the ECP on solidification microstructure and provided a novel and feasible approach to evaluate and optimise the structure refinement of the ECP.

Piezoelectric energy harvester can replace the battery and provide energy for most kinds of micro devices. And due to its advantages of considerable output power and high output voltage, it has bright prospects. This paper presents a piezoelectric energy harvester based on coupled oscillator model utilizing a L-shaped cantilever beam to collect the vibration energy of the vehicle with the frequency band from 5 Hz to 25 Hz. The finite element analysis of the designed piezoelectric energy harvester is carried out by running ANSYS simulation software, including modal analysis, transient response analysis and harmonic response analysis. The results shows that under the coupling, the amplitude-frequency characteristic curve of each oscillator has two peak points, which widens the working frequency band of the energy harvester. Meanwhile, experimental research is carried out on the collector prototype. By analyzing the experimental results, the natural frequency of oscillator 1 is about 17.1 Hz, and the natural frequency of oscillator 2 is about 21.1 Hz. Therefore, these natural frequencies meet the need to collect vibration energy of 5 Hz to 25 Hz. In addition, by comparing the frequency response curves of the open circuit output voltage of the energy collectors working independently and under coupling, the results show that the operating frequency band of the energy collector is broadened under coupling.