System in package

A system in a package (SiP) or system-in-package is a number of integrated circuits (ICs) enclosed in one chip carrier package or encompassing an IC package substrate that may include passive components and perform the functions of an entire system. The ICs may be stacked using package on package, placed side by side, and/or embedded in the substrate. The SiP performs all or most of the functions of an electronic system, and is typically used when designing components for mobile phones, digital music players, 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. SiPs are like systems on a chip (SoCs) but less tightly integrated and not on a single semiconductor die. SiP dies can be stacked vertically or tiled horizontally, with techniques like chiplets or quilt packaging, unlike less dense multi-chip modules, which place dies horizontally on a carrier. SiPs connect 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. Many different 3D packaging techniques have been developed for stacking many fairly standard chip dies into a compact area. SiPs can contain several chips—such as a specialized processor, DRAM, flash memory—combined with passive components—resistors and capacitors—all mounted on the same substrate. This means that a complete functional unit can be built in a multi-chip package, so that few external components need to be added to make it work. This is particularly valuable in space constrained environments like MP3 players and mobile phones as it reduces the complexity of the printed circuit board and overall design. Despite its benefits, this technique decreases the yield of fabrication since any defective chip in the package will result in a non-functional packaged integrated circuit, even if all other modules in that same package are functional.