Multi-Chip Module

A Multi-Chip Module (MCM) is a specialized electronic package where multiple integrated circuits (ICs), semiconductor dies or other modules are packaged in such a way as to facilitate their use as a single IC. The MCM itself will often be referred to as a "chip" in designs, thus illustrating its integrated nature.

Multi-Chip Modules come in a variety of forms depending on the complexity and development philosophies of their designers. These can range from using pre-packaged ICs on a small printed circuit board (PCB) meant to mimic the package footprint of an existing chip package to fully custom chip packages integrating many chip dies on a High Density Interconnection (HDI) substrate.

Multi-Chip Module packaging is an important facet of modern electronic miniaturization and micro-electronic systems. MCMs are classified according to the technology used to create the HDI (High Density Interconnection) substrate.

* MCM-L - laminated MCM. The substrate is a multi-layer laminated PCB (Printed circuit board).
* MCM-D - deposited MCM. The modules are deposited on the base substrate using thin film technology.
* MCM-C - ceramic substrate MCMs, such as LTCC.

Chip stack MCMs

A relatively new development in MCM technology is the so-called "chip-stack" package. Certain ICs, memories in particular, have very similar or identical pinouts when used multiple times within systems. A carefully designed substrate can allow these dies to be stacked in a vertical configuration making the resultant MCM's footprint much smaller (albeit at the cost of a thicker or taller chip). Since area is more often at a premium in miniature electronics designs, the chip-stack is an attractive option in many applications such as cell phones and personal digital assistants (PDAs).

Examples of MCM technologies

*IBM Bubble memory MCMs (1970s)
*Intel Pentium Pro, Pentium D Presler [http://www.theinquirer.org/?article=25746] , Xeon Dempsey and Clovertown, and Core 2 Quad Kentsfield
*Sony memory sticks
*Xenos, a GPU designed by ATI Technologies for the Xbox 360, with eDRAM
*POWER2, POWER4 and POWER5 from IBM

ee also

* System in package
* Hybrid integrated circuit

External links

* Multi-Chip Modules [http://www.cmac.com/products-and-applications/MCMs.php C-MAC MicroTechnology]
* [http://www.aws.cit.ie/research/wirelessnodes/index.htm Multichip Module Technology (MCM) or System on a Package (SoP)]