I have a project on the horizon that will use a 19 x 19, 50 mil pitch BGA 
(357 pins).  I have no experience with BGA's and could use some help on 
getting the traces out from the center of the pattern.  If I apply our std 
SMT pcb design rules and use a .012 via with a .028 pad, the real estate 
disappears in a hurry and I'll need 20 layers just getting out of the BGA.  
What are you doing?  Are you using a via hole smaller than .012, or crushing 
down the via pads much smaller than required for normal fab allowance?  Are 
you using a very small via hole in the BGA solder pad?  I know AT&T has been 
putting via holes in SMT footprints for years using (I think) a .007 hole. .. 
AT&T are you out there?                                            

Sure would appreciate any input.

Thanks

gary ..

Bailey Controls Co.