Flux-induced porous structures in Cu-SnAg solidliquid-interdiffusion microbump interconnects

Nanoporous intermetallic compounds (IMCs) are a promising option for interconnects in 3D integration of various electronic components. These combine the high thermal and mechanical stability of Cu-Sn-SLID (solid-liquid interdiffusion) interconnects with a strongly reduced processing time. In this paper we address the influence of the flux on the nanostructure of the interconnects. The further dissolution of Sn from the already known lamellar network of Cu$_{\mathbf{3}}$Sn is reported for the first time and analyzed in detail.