BGA 

    Ball Grid Array. A popular surface mount chip package that uses a grid of solder balls as its connectors. Available in plastic and ceramic varieties, BGA is noted for its compact size, high lead count and low inductance, which allows lower voltages to be used. BGA chips are easier to align to the printed circuit board, because the leads, which are called "solder balls" or "solder bumps," are farther apart than leaded packages. Since the leads are underneath the chip, BGA has led the way to chip scale packaging (CSP) where the package is not more than 1.2x the size of the semiconductor die itself