Description
The BGA is descended from the pin grid array (PGA), which is a package with one face covered (or partly covered) with pins in a grid pattern. These pins conduct electrical signals from the integrated circuit to the printed circuit board (PCB) on which it is placed. In a BGA, the pins are replaced by balls of solder stuck to the bottom of the package. These solder spheres can be placed manually or with automated equipment. The solder spheres are held in place with a tacky flux until soldering occurs. The device is placed on a PCB with copper pads in a pattern that matches the solder balls. The assembly is then heated, either in a reflow oven or by an infrared heater, causing the solder balls to melt. Surface tension causes the molten solder to hold the package in alignment with the circuit board, at the correct separation distance, while the solder cools and solidifies.
Read more about this topic: Ball Grid Array
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