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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 or "chips"), semiconductor dies and/or other discrete components are integrated, usually onto a unifying substrate, so that in use it can be treated as if it were a larger IC. Other terms, such as "hybrid" or "hybrid integrated circuit", also refer to MCMs. The individual ICs that make up an MCM are known as Chiplets. Intel and AMD are using MCMs to improve performance and reduce costs, as splitting a large monolithic IC into smaller chiplets allows for more ICs per wafer, and improved yield, as smaller dies have a reduced risk of getting destoyed by dust particles during semiconductor fabrication. Each chiplet is physically smaller than a conventional monolithic IC die, (A monolithic IC is an IC package contining a single IC).  An example of MCMs in use for mainstream CPUs is AMD's Zen 2 design.
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 substrate.
- MCM-L – laminated MCM. The substrate is a multi-layer laminated printed circuit board (PCB).
- MCM-D – deposited MCM. The modules are deposited on the base substrate using thin film technology.
- MCM-C – ceramic substrate MCMs, such as low temperature co-fired ceramic (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). With the use of a 3D integrated circuit and a thinning process, as many as ten dies can be stacked to create a high capacity SD memory card.
Examples of multi-chip technologies
- IBM Bubble memory MCMs (1970s)
- IBM 3081 mainframe's thermal conduction module (1980s)
- Superconducting Multichip modules (1990s)
- Intel Pentium Pro, Pentium D Presler TheINQUIRER - news, reviews and opinion for tech buffs, Xeon Dempsey and Clovertown, Core 2 Quad (Kentsfield, Penryn-QC and Yorkfield), Clarkdale, Arrandale, and Haswell-H
- Micro-SD cards and Sony memory sticks
- Xenos, a GPU designed by ATI Technologies for the Xbox 360, with eDRAM
- POWER2, POWER4, POWER5 and POWER7 from IBM
- IBM z196
- AMD processors for Socket G34 and Socket SP3
- Nintendo's Wii U has its CPU, GPU, and onboard VRAM (integrated into the GPU) on one MCM.
- VIA Nano QuadCore
- Flash and RAM memory combined on a PoP by Micron
- Samsung MCP solutions combining mobile DRAM and NAND storage.
- Intel Core i5 CPUs launched in 2010 with two chips: 32 nm CPU and 45 nm integrated GPU on the same PCB
- AMD Ryzen Threadripper and Epyc CPUs based on Zen or Zen+ architecture are MCMs of two or four chips (Ryzen based on Zen or Zen+ is not MCM and consist of one chip)
- AMD Ryzen and Ryzen Threadripper and Epyc CPUs based on Zen2 architecture are MCMs of two or four or eight chips containing CPU cores and one bigger I/O chip
3D multi-chip modules
- System in package (SIP)
- Hybrid integrated circuit
- Chip carrier Chip packaging and package types list
- Single Chip Module (SCM)
- Rao Tummala, Solid State Technology. “SoC vs. MCM vs SiP vs. SoP.” Retrieved August 4, 2015.
- "Chiplet - WikiChip". en.wikichip.org.
- Simonite, Tom (November 6, 2018). "To Keep Pace With Moore's Law, Chipmakers Turn to 'Chiplets'". Wired – via www.wired.com.
- "Upscaled: This is the year of the CPU 'chiplet'". Engadget.
- Jon Worrel (15 April 2012). "Intel migrates to desktop Multi-Chip Modules (MCMs) with 14nm Broadwell". Fudzilla.
- Richard Chirgwin, The Register. “Memory vendors pile on '3D' stacking standard.” April 2, 2013. February 5, 2016.
- High-performance MCM interconnection circuits and fluxoelectronics, Proc. 1992 IEEE Multi-Chip Module Conf., Los Alamitos, CA: IEEE Computer Society Press, 1992, pp. 175-178. https://ieeexplore.ieee.org/document/201478
- Multichip module using multilayer YBa2Cu3O7−δ interconnects, Appl. Phys. Lett. 62, 1435-1437 (1993) https://aip.scitation.org/doi/10.1063/1.108652
- Satoru Iwata, Iwata Asks. “Changes in Television.” Retrieved August 4, 2015.
- "MCP (Multichip Package) | Samsung Semiconductor". www.samsung.com.
- "NAND based MCP | Samsung Memory Link". samsung.com.
- "e-MMC based MCP | Samsung Memory Link". samsung.com.