Ball grid array (BGA) is a type of surface mount technology (SMT) that is derived from pin grid array (PGA) technology. It uses a grid of solder balls that conduct electrical signals from the integrated circuit board. Although derived from pin grid array, ball grid array does not use pins but solder balls, which are placed on the printed circuit board (PCB). The PCB supports and connects the electronic components by using conductive printed wires.
PGA, which has hundreds of pins, makes soldering difficult, but BGA has solder balls that are spaced evenly apart so they aren’t susceptible to the same risk of bridging that is common with PGA. The solder balls are placed on the bottom of the package, forming a grid pattern, and then heated. Utilizing the surface tension during the melting of the solder balls, the package may be aligned with the circuit board. The solder balls will cool off and solidify with an accurate and consistent distance between them.
BGA conducts and insulates layers with a green-colored solder mask, although other colors such as black, red, blue, or white may be used. The conducting layers are thin copper foils that may be specified in micrometers or ounces per foot. These conducting layers are bonded together with epoxy resin composite fiber prepreg. They are insulated with dielectric materials.
Every BGA is identified by the number of sockets it contains. For example, BGA 437 contains 437 sockets while BGA 411 has 411 sockets. BGAs can have different form factor variants.