Three-dimensional and 2.5 dimensional interconnection technology: State of the art

Three-dimensional (3D) packaging with through-silicon-vias (TSVs) is an emerging technology featuring smaller package size, higher interconnection density, and better performance; 2.5D packaging using silicon interposers with TSVs is an incremental step toward 3D packaging. Formation of TSVs and interconnection between chips and/or wafers are two key enabling technologies for 3D and 2.5D packaging, and different interconnection methods in chip-to-chip, chip-to-wafer, and wafer-to-wafer schemes have been developed. This article reviews state-of-the-art interconnection technologies reported in recent technical papers. Issues such as bump formation, assembly/bonding process, as well as underfill dispensing in each interconnection type are discussed.