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Purpose - Because of the need for electronics use at temperatures beyond 150 C, high temperature resistant interconnection technologies like transient liquid phase (TLP) soldering and silver sintering are being developed which are not only replacements of high-lead solders, but also open new opportunities in terms of temperature resistance and reliability. The paper aims to address the thermo-mechanical reliability issues that have to be considered if the new interconnection technologies will be applied. Design/methodology/approach - A TLP soldering technique is briefly introduced and new challenges concerning the thermo-mechanical reliability of power devices are worked out by numerical analysis (finite element simulation). They arise as the material properties of the interconnect materials differ substantially from those known for soft solders. The effective material responses of the new materials are determined by localized unit cell models that capture the inhomogeneous structure of the materials. Findings - It is shown that both the TLP solder layer and the Ag-sinter layer have much less ductility and show less creep than conventional soft solders. The potential failure modes of an assembly made by TLP soldering or Ag sintering change. In particular, the characteristic low cycle fatigue solder failures become unlikely and are replaced either by metallization fatigue, brittle failure of intermetallic compound, components, or interfaces. Originality/value - A variety of new failure risks, which have been analyzed theoretically, can be avoided only if they are known to the potential user of the new techniques. It is shown that an optimal reliability will be strongly dependent on the actual assembly design

The current reliability problems related to bonding wires and solder paste are shown, and possible solutions are discussed. Five morphological categories of failure modes are identified. We set out the basic principles for specifying solder pastes, especially with regard to the powder used. The continuing trend towards miniaturization of SMT assembly production demands a commensurate reduction in powder‐particle size, and the use of a compatible fluxing system. A judicious selection of the powder type can improve printing and soldering quality, and thus expand the process‐operation window. Comparing wire‐bonding technology with solder joints for Flip Chip applications, failure mechanisms, like Kirkendall voids, are present and will be discussed.

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