What are Interposers?
Meet the Connector: Interposers
Interposers, or interposer connectors, are compression-mounted interconnect devices that are positioned between boards or sockets to allow an electrical signal to pass through very quickly. They have a wider pitch than a traditional connector, thus enabling the easy rerouting of connections, and provide designers with a flexible, removeable interface. The wide pitch provides a much larger channel for electrical signals, reducing the amount of energy needed to transmit signals, minimizing resistance/capacitance (RC) delay, and shortening the distance between units in a system. They can be very thin, which enables them to serve in small packages. Some interposers feature spring pin technology. Interposers are often used in BGAs (ball grid arrays) or multichip modules. Optical interposers are also available.
Three materials are used for interposers: Silicon, glass, and organic materials. Silicon is a proven material and the most commonly used, although it presents thermal and cost challenges. Glass offers high density at a lower cost but this material has lower thermal conductivity and is prone to cracking in the manufacturing process. Organic materials have a lower pitch and less mechanical stability. Glass and organic interposers are still in a period of significant development.
The term interposer comes from the Latin word interpōnere, meaning “to put between.”
Interposer Design Notes
2.5D, also called interposer technology, integrates several electronic devices inside a single package by positioning them side-by-side on an interposer that serves as a base. The interposer is a foundational element of upcoming innovations in 2.5D and 3D packaging technologies.
Using an interposer is preferable to reballing lead-free BGA devices in RoHS-exempt applications, as reballing can introduce contamination, weakening the solder joint while also exposing the devices to extra reflow cycles.
Silicon transposers are expensive and add $30-$100 to the cost of a chip, depending on its size. Costs will keep this interface limited to specific high-speed applications.
Interposer technology is in a period of intense innovation. Active interposer technologies, materials research, and evolving semiconductor designs will bring changes to this area in the years ahead.
Markets, Sectors, and Applications
Military and Aerospace, Datacom, and any market that requires high-speed computing (networking, servers, ASICS, CPUs)
Interposer Related products:
- Mezzanine Connectors
- Board-to-Board Connectors
- Connector Adaptors
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