BGA, its full name is Ball Grid Array, which is kinds of packaging method in which integrated circuits use organic carrier boards.
The PCB boards with BGA have more interconnect pins than ordinary PCBs. Each point on the BGA board can be soldered independently. The entire connections of these PCBs are scattered in the form of a uniform matrix or surface grid. The design of these PCBs allows the entire bottom surface to be easily used instead of just using the peripheral area.
The pins of the BGA package are much shorter than the ordinary PCB because it has only a perimeter type shape. For this reason, it can provide better performance at higher speeds. BGA welding requires precise control and is more often guided by automatic machines.
We can solder the PCB with very small BGA size even the distance between the ball is only 0.1mm.