Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration IZM

Filters
2
Reset filters

Settings
Now showing 1 - 2 of 2
  • Publication
    Formation of Ag Dendrites During the Electrolytic Migration Between Ag-4Pd Wire Couple in Water Under Bias
    ( 2023)
    Chen, Chun-Hao
    ;
    Lin, Yancheng
    ;
    Wu, Poching
    ;
    Chuang, Tung Han
    The growth of Ag dendrites induced by the Ag ion migration between Ag-4Pd alloy wire couples immersed in pure water under bias was observed, and its failure mode leading to a short circuit was investigated. The experimental results indicated that the time of dendrite contact and short circuit decreased obviously with increases in voltage and wire pitch. In contrast, the formation time of hydrogen bubbles and Ag spikes in the initial stage of water drop tests decreased slightly with increases in applied voltage, leading to drastic increases in the Ag dendrite growth rate at higher voltages. During the electrolytic migration process, the outer surface of the anode wire oxidized into a continuous Ag2O layer with a porous grain structure. In addition, Ag+ ions were reduced to crystallographic Ag2O particles that formed a layer concealing the anode wire. Summarizing the observations of Ag dendrite growth and the Ag2O layer formed on cathode and anode wires, respectively, a reaction mechanism for the electrolytic migration of Ag-4Pd wire couple is proposed.
  • Publication
    Intermetallic growth and thermal impedance at the In32.5Bi16.5Sn/Cu interface
    ( 2023)
    Chen, Chun-Hao
    ;
    Yang, Chunglin
    ;
    Chuang, Tung Han
    Present developing trends in the miniaturization and power escalation on electronic components have driven research interest in thermal interface materials (TIMs) to solve the fundamental issue of heat dissipation. Among the various TIMs, the In32.5Bi16.5Sn low melting alloy (LMA) has drawn much attention owing to its low melting point and great bondability, which could mitigate the warpage issue and provide very low thermal interface resistance. In this study, the Cu/In32.5Bi16.5Sn/Cu structure was used to simulate the practical conditions of the application of TIM in joining the substrate and heat sink. The thermal properties before and after an aging test at 80 °C were measured with a thermal tester, and the growth kinetics of the intermetallic compound (IMC) at the In32.5Bi16.5Sn/Cu interface were investigated. Without fast dissolution of Cu into the In32.5Bi16.5Sn alloy, the growth kinetics of the IMC at the interface were found to be diffusion-controlled at the temperature studied. It was found that the main change in the Cu/In32.5Bi16.5Sn/Cu system after the aging test was the thickening of the IMC, and the interface was free of cracks. As the aging time increased, the thermal impedance increased to twice that of the initial value, showing parabolic degradation, which is relevant to the growth kinetics of the IMC at the interface. Implications for the degradation of the thermal performance and further research are also discussed.