Ball Grid Array Variants Printed circuit board
To make it easier to use ball grid array devices, most BGA packages only have balls in the outer rings of the package, leaving the innermost square empty.
Intel used a package designated BGA1 for their Pentium II and early Celeron mobile processors. BGA2 is Intel's package for their Pentium III and some later Celeron mobile processors. BGA2 is also known as FCBGA-479. It replaced its predecessor, BGA1.
For example, the "Micro-FCBGA" (Flip Chip Ball Grid Array) is Intel's current BGA mounting method for mobile processors that use a flip chip binding technology. It was introduced with the Coppermine Mobile Celeron. Micro-FCBGA has 479 balls that are 0.78 mm in diameter. The processor is affixed to the motherboard by soldering the balls to the motherboard. This is thinner than a pin grid array socket arrangement, but is not removable.
The 479 balls of the Micro-FCBGA Package (a package almost identical to the 478-pin Socketable Micro-FCPGA Package) are arranged as the 6 outer rings of a 1.27 mm pitch (20 balls per inch pitch) 26x26 square grid, with the inner 14x14 region empty.