Got to get a packet or two [stacked multilayer chip assemblies]

System in package (SiP), as it is being called, is a combination of two or more die stacked together on an interconnection substrate, all within a single package. Typically, there is some sort of processor chip coupled to either memory, a high-performance analogue IC, or to a micro-electro-mechanical system (MEMS) device. A SiP, though, could contain all these elements. This article discusses the challenges faced in SiP technology.