A SiP (System-in-Package) or system in a package is a number of integrated circuits enclosed in one or more chip carrier packages that may be stacked using package on package. The SiP performs all or most of the functions of an electronic system, and is typically used inside a mobile phone, digital music player, etc. Dies containing integrated circuits may be stacked vertically on a substrate. They are internally connected by fine wires that are bonded to the package. Alternatively, with a flip chip technology, solder bumps are used to join stacked chips together. A SiP is like a system on a chip (SoC) but less tightly integrated and not on a single semiconductor die.
SiP dies can be stacked vertically or tiled horizontally, unlike less dense multi-chip modules, which place dies horizontally on a carrier. SiP connects the dies with standard off-chip wire bonds or solder bumps, unlike slightly denser three-dimensional integrated circuits which connect stacked silicon dies with conductors running through the die.
