Hi,
I have a question about usage of BB's in a dense design over 14 layers on a 95x95mm PCB. I used an old project that was similar to what I wanted (not designed by me) and it had a stack-up layers 1-2, 2,13, and 13-14 which seemed sensible to me as it gave me access to all inner layers with one via and kept the top and bottom layers free of all vias not required for them, it also helped fan-out of the SoC and the other ball grid devices (RAM etc) and I could control the positions of the inner vias.
I gave the proposed stack-up to the PCB-A manufactures for them to get PCB's and they said that while it was not uncommon to have such stack-ups a lot of manufactures cannot make it as it requires laser drilling.
So my question is what do you do when faced with this density. Do you use PTH for most of the layout? Am I missing a trick? Or is it common for this type of board to use the blind and buried vias similar to above?
Thanks Jessica