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Warpage has always been an important issue in electronic packaging, especially for fan-out and flip-chip chip scale packages (fcCSP). The molded underfill for encapsulation plays a key role in warpage control. It is critical to establish a fundamental understanding of the properties of cure-induced shrinkage and viscoelasticity, and the effects of pressure, temperature, volume variation, and degree of cure on package warpage.In this study, the cure-dependent shrinkage and cure-dependent viscoelasticity of a molded underfill are carefully characterized during in-molding and post molding cure (PMC) thermal processes. A plunger dilatometer is used for shrinkage characterization, and the volume change is described by pressure, volume change, temperature, and degree of cure relations. In addition, the cure-dependent properties are characterized by other two techniques, including cure kinetics by differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was found that the volume change after the gel point is the dominant factor for package warpage. The package warpage evolution was modeled by finite element analysis. Our predictive models are not only in good agreement with the experimental thermal shadow moire result, but also effectively evaluate the effect for shrinkage and CTE/modulus. The results indicate that warpage at high temperature is highly sensitive to the CTE/Modulus of MUF.

Power module with high power density and high heat dissipation structure has been developed because of increasing requirement for high-power electric products. Power cycling test (PCT) was often adopted to assess to reliability of power module while the cyclic load was applid in power chip. This study investigates the electro-thermo-mechanical behavior of high-power module by using numerical analysis, and assesses its reliability through PCT. First, the current density, corresponding temperature distribution and mechanical behavior of high-power module are predicted by using electro-thermal coupling and thermo-mechanical analysis. In order to satisfy automotive electronics application, the cycling period of minute-level was chosen and applied in high-power module to conduct the reliability test.

A high current load may cause the Joule heating, subsequently raising the chip temperature in a conventional power module. Temperature excursion in power chip may generate thermal stress, induce failure and reduce its reliability. Double-sided power module is a crucial structure to provide another heat dissipation path and efficiently reduce chip temperature. This study estimate the thermal and reliability analysis of double-sided power module by using copper bump as an interconnection under different cooling condition. The connection layout can be designed more flexible by using bump interconnection in double-sided power module. The concept of dummy ball also utilized to reduce the mechanical strain or stress of copper bump and improve its reliability in a power module.

In this investigation, a SiP (system-in-package) which consists of a very low-cost interposer with through-silicon holes (TSHs) and with chips on its top- and bottom-side (a real 3D IC integration) is studied. Emphasis is placed on the fabrication of a test vehicle to demonstrate the feasibility of this SiP technology. The design, materials, and process of the top-chip, bottom-chip, TSH interposer, and final assembly will be presented. Shock and thermal cycling tests will be preformed to demonstrate the integrity of the SiP structure.

This paper presents a capacitor discharge sintering process with a homemade silver-nickel paste for thermoelectric element interconnections. The paste is a 75 nm silver/nickel composite mixture. Without using any specific atmosphere control, the capacitor discharge is capable of nanoparticle sintering with time-efficient process at room temperature. A 0.01 F capacitor is serially connected to the sample and charged to 10 V (0.5 Joule) for the sintering process. To evaluate the conductivity of the sintered composite, the conductive material is screen-printed on an Al 2 O 3 ceramic substrate; it forms a rectangular tunnel to bridge two silver electrodes. After sintering process, the resistance of the screened conductive pass-way is dropped from 9.47 Ω to 0.35 Ω. The bonding strength and high temperature resistance test results of the sintered composite is also presented in this paper. Without generating a lot of heat, the sintering process can be applicable to flexible electronics.

In a high power module, a high electrical load may cause electromigration and induce the joule heating, subsequently raising the chip temperature. Temperature excursion in the IGBT chip may produce thermal stress, inducing failure in the metal wire and chip. Those failure modes degrade the reliability of a power module. This study elucidates the coupling behavior of a high power module through electro-thermal coupling analysis and thermo-mechanical analysis. Additionally, the configuration design of an aluminum wire is simulated and implemented. Related design parameters, e.g., wire arrangement position, wire number, wire bonding perimeter and wire height, are studied and the design trend of a metal wire is analysed and suggested as well.

Due to the lack of advanced technology and difficulties in sample preparing, direct measurement of thermal conductivity for thin-film thermoelectric material is rarely reported in literatures. In this work, there are four types of thermoelectric thin films measured for their intrinsic thermal conductivity by using a modified parallel-strip technique. These four types of thermoelectric thin films are of Bi-Te and Sb-Te compositions, resulting from electrodeposition process with different aqueous solutions. From the measurement results, three types of the films shown quite low intrinsic thermal conductivity less than 0.5 Wm−1 K−1; and one type of the films can not be measured due to sample preparing problem. According to the scanning electron microscope observations, the grain boundaries in the thermoelectric thin films are probably the cause that results in their low thermal conductivity and the fragile structure is the cause of difficulty for the sample preparation.