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A multi-chip module (MCM) is generically an electronic assembly (such as a package with a number of conductor terminals or ``pins") where multiple integrated circuits (ICs), semiconductor dies and/or other discrete components are integrated, usually onto a unifying substrate, so that in use it is treated as if it were a single component (as though a larger IC). Other terms, such as "hybrid" or Hybrid integrated circuit, also refer to MCMs.
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). After a thinning process, as many as ten dies can be stacked to create a high capacity SD memory card.
Examples of MCM technologies
- IBM Bubble memory MCMs (1970s)
- IBM 3081 mainframe's thermal conduction module (1980s)
- Intel Pentium Pro, Pentium D Presler , Xeon Dempsey and Clovertown, Core 2 Quad (Kentsfield and Yorkfield), Clarkdale, Arrandale, and Haswell-H
- Sony memory sticks
- Xenos, a GPU designed by ATI Technologies for the Xbox 360, with eDRAM
- POWER2, POWER4, POWER5 and POWER7 from IBM
- z196 from IBM
- AMD processors for Socket G34
- Nintendo's Wii U has its CPU, GPU, and onboard VRAM (integrated into the GPU) on one MCM.
- VIA Nano
- Flash and RAM memory combined on a PoP by Micron
- System in package (SIP)
- Hybrid integrated circuit
- Chip carrier Chip packaging and package types list