"mcjonster" <
mcjonster@...> writes:
> Can I use a 2 sided board for a BGA and route wires between solder
> pads and put vias in there also or am I stuck with 4+ layer board?
It depends on the chip and what you want to do with it. For example,
I just did a layout (not etched) for a 6x8 (=48) BGA adapter that was
single sided:
http://www.delorie.com/electronics/adapters/In theory, you can do larger BGAs as long as you won't have signal
integrity or power spike issues - the inner planes help mitigate
those. You can route the outer four rows of balls out with two
layers, but you still need to get your power and ground in there -
usually those are on the inner balls, and you'll need bypass caps in
there.
Note, however, that doing your own PCBs at home with BGAs will only
work if you can do plated vias - a wire sticking up under there will
cause problems.