You can use the example Gerber (.gbr) files and the printed circuit board (PCB) layout files (Accel PCB layout tool) provided on this web site as guidelines for laying out 256-, 484-, and 672-pin FineLine BGA™ packages on your PCB. These files are meant to be a guide only; you should refer to the layout specifications provided by your PCB vendor when actually laying out your PCB.
These Gerber and PCB files route all the I/O pins (except for No Connect pins) on the FineLine BGA package. Separate VCCINT, VCCIO, and GND planes are used to route VCCINT, VCCIO, and GND pins, respectively. Your board layout may be simpler because your design may not use all the I/O pins. Refer to the appropriate readme.txt file (contained in each zip file) for details on the Gerber file extensions.