What is System in a Package?

System-in-Package (SiP) is an integration approach in microelectronics that is technically located between monolithic on-chip integration (system-on-a-chip, SoC) on a die (unpackaged semiconductor chip) and on-board integration of discrete components on a printed circuit board (PCB) or on a multi-chip module (MCM). Passive and active components as well as other components are combined in a package (called IC package) using microsystem technologies using packaging technology. Related to SiP in the structure are the Package-on-Package (PoP), in which different semiconductor chips are combined on top of each other.

In contrast to the multi-chip modules that have been manufactured for a long time, which have a planar (i.e. two-dimensional) structure and thus belong to the electronic printed circuit boards, the vertical integration of components (3D, 2.5D SiP) can also be realized in a SiP. The electrical connections between the individual dies are carried out either by bonding wires, as conductive thin films on side edges of the dies or as through-silicon via (TSV).

SoC and SiP represent two important manufacturing processes for complex integrated semiconductor devices. In the case of SiP, dies can be used that are based on different materials or have been manufactured with different process structures. In addition, discrete peripheral components can be integrated into the housing in a SiP. With the SiP, the production (packaging) is more expensive than with the SoC, while a complete integration of all functionalities on one chip is usually more expensive. Which variant is cheaper depends very much on the functionality of the circuit.

For designing SiPs, there is design software from the major EDA vendors. In the case of SiP, it makes economic sense to use known-good-die tests to check the absence of defects of the chips before integration.

A classic multi-chip module consists of several individual microchips (or dies) that are housed planar (next to each other) in a common package and look like one chip on the outside, function and use. From the outside, such chips are not directly recognizable, but look like many others. Today, the term MCM is also applied to modules that, in addition to semiconductor dies, contain micromechanical elements or discrete passive components such as capacitors or resistors in SMD designs. Such MCMs as well as MCMs with vertically arranged components correspond much more to the characteristics of a system-in-package.