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Copper sinter paste has been recently established as a robust die-attach material for high -power electronic packaging. This paper proposes and studies the implementation of copper sinter paste materials to create top-side interconnects, which can substitute wire bonds in power packages. Here, copper sinter paste was exploited as a fully printed interconnect and, additionally, as a copper clip-attach. The electrical and thermal performances of the copper-sinter paste interconnections (“sinterconnects”) were compared to a system with wire bonds. The results indicate comparable characteristics of the sinterconnect structures to the wire-bonded ones. Moreover, the performance of copper sinterconnects in a power module was further quantified at higher load currents via finite element analysis. It was identified that the full-area thermal and electrical contact facilitated by the planar sinterconnects can reduce ohmic losses and enhance the thermal management of the power packages.

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Bump-less copper (Cu) bonding is currently the most attractive approach for fine-pitch (< 20 µm) 3D integration due to its compatibility with the wafer back-end-of-the-line fabrication process. In this study, themocompression bonding of bump-less Cu pads with a diameter of 4 µm and a pitch size of 10 µm was pursued, while chemical mechanical polishing (CMP)-processed Cu pads enclosed in SiO2 were employed with both protruded and recessed topographies. The effects of Cu topography (protruded or recessed) and bonding temperature on the electrical and microstructural properties of the die bonds as well as mechanical bonding strength were investigated. It was found that thermocompression bonding of CMP-processed Cu can be realized at shorter processing times, lower bonding temperatures, and pressures than standard electroplated Cu bonding. The bonding yield of the three configurations, i.e. protruded-protruded, protruded-recessed, and recessed-recessed Cu pads was also compared.

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