17/09/2004 01:29:00, Jamie Morken <jmorken@shaw.ca> 
wrote:

>Did you decide to use buried/blind vias to route this chip or 
microvias?

Nope - Balloon3 is on crude old technology. Still likely to be 6 or 8 
layers, (of which 2 are planes), but no hard-to-fab PCB features. 
Lesson learned from Balloon2. Using blind vias / microvias is 
tempting - if this wasn't trying to be easily manufactured by all-
comers, I'd be doing it that way, and using smaller packages for 
the XScale chip and the FPGA. As it is, the compromise is towards 
manufacturability. (The larger package of PXA27X is also likely 
(hopefully) to be around for longer than the tiny cellphone-
targetted versions, which will become last-year's-chip painfully 
quickly. 

Steve