Abstract:
Embodiment of the present disclosure are directed to methods for forming an LMI landing pad on a silicon wafer. The method includes forming, on a substrate, a redistribution layer (RDL); forming, on the RDL and the substrate, a passivation layer covering the substrate and the RDL; forming, on the passivation layer, a patternable dielectric material layer; processing the patternable dielectric material layer to expose a portion of the passivation layer covering the RDL; processing the portion of the passivation layer covering the RDL to expose a portion of the RDL; and forming, on the exposed portion of the RDL, an LMI landing pad. The resulting wafer can include a redistribution line having a top portion and a sidewall portion; a passivation layer covering the sidewall portion; a dielectric layer covering the passivation layer; and a metal interface covering the top portion of the redistribution line.
Abstract:
A stacked-chip assembly including a plurality of IC chips or die that are stacked, and electrically coupled by solder bonds. In accordance with some embodiments described further below, the solder bonds are to contact a back-side land that includes a diffusion barrier to reduce intermetallic formation and/or other solder-induced reliability issues. The back-side land may include an electrolytic nickel (Ni) barrier layer separating solder from a back-side redistribution layer trace. This electrolytic Ni may be of high purity, which at least in part, may enable the backside metallization stack to be of minimal thickness while still functioning as a diffusion barrier. In some embodiments, the back-side land composition and architecture is distinct from a front-side land composition and/or architecture.