Pin grid array

The underside of a FC-PGA package (the die is on the other side)

A flip-chip pin grid array (FC-PGA or FCPGA) is a form of pin grid array in which the die faces downwards on the top of the substrate with the back of the die exposed. This allows the die to have a more direct contact with the heatsink or other cooling mechanism.

The FC-PGA was introduced by Intel with the Coppermine core Pentium III and Celeron[2] processors based on Socket 370, and was later used for Socket 478-based Pentium 4[3] and Celeron processors. FC-PGA processors fit into zero insertion force (ZIF) Socket 370 and Socket 478-based motherboard sockets; similar packages have also been used by AMD. It is still used today for mobile Intel processors.

A ceramic pin grid array (CPGA) is a type of packaging used by integrated circuits. This type of packaging uses a ceramic substrate with pins arranged in a pin grid array. Some CPUs that use CPGA packaging are the AMD Socket A Athlons and the Duron.

A CPGA was used by AMD for Athlon and Duron processors based on Socket A, as well as some AMD processors based on Socket AM2 and Socket AM2+. While similar form factors have been used by other manufacturers, they are not officially referred to as CPGA. This type of packaging uses a ceramic substrate with pins arranged in an array.

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  A 1.2 GHz VIA C3 microprocessor in a ceramic package
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  133 MHz Pentium chip in a ceramic package

An organic pin grid array (OPGA) is a type of connection for integrated circuits, and especially CPUs, where the silicon die is attached to a plate made out of an organic plastic which is pierced by an array of pins which make the requisite connections to the socket.

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  The underside of a Celeron-400 in a PPGA
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  An OPGA CPU. Note the brown color – many OPGA parts are colored green. The die is in the center of the device, and the four gray circles are foam spacers to relieve pressure from the die, caused by the heat sink.

The topside of a Celeron-400 in a PPGA packing

Plastic pin grid array (PPGA) packaging was used by Intel for late-model Mendocino core Celeron processors based on Socket 370.[4] Some pre-Socket 8 processors also used a similar form factor, although they were not officially referred to as PPGA.

Underside of a Pentium 4 in a PGA package

The staggered pin grid array (SPGA) is used by Intel processors based on Socket 5 and Socket 7. Socket 8 used a partial SPGA layout on half the processor.

An example of a socket for a staggered pin grid array package

View of the socket 7 321-pin connectors of a CPU

It consists of two square arrays of pins, offset in both directions by half the minimum distance between pins in one of the arrays. Put differently: within a square boundary the pins form a diagonal square lattice. There is generally a section in the center of the package without any pins. SPGA packages are usually used by devices that require a higher pin density than what a PGA can provide, such as microprocessors.

A stud grid array (SGA) is a short-pinned pin grid array chip scale package for use in surface-mount technology. The polymer stud grid array or plastic stud grid array was developed jointly by the Interuniversity Microelectronics Centre (IMEC) and Laboratory for Production Technology, Siemens AG.[5][6]

The reduced pin grid array was used by the socketed mobile variants of Intel's Core i3/5/7 processors and features a reduced pin pitch of 1 mm,[7] as opposed to the 1.27 mm pin pitch used by contemporary AMD processors and older Intel processors. It is used in the G1, G2, and G3 sockets.