--- Quote Start ---
i will share my experience after we will solve these problems. so that everyone can use this knowledge in future.
--- Quote End ---
That is an excellent attitude.
--- Quote Start ---
my response will not be soon though, because a motherboard will have almost a size of an A4 paper and lots of high speed components on it.
--- Quote End ---
In that case, here's some more advice. If your high-speed is in the Gbps range, then you may have to consider using Megtron or Nelco 4000-SI materials. If that is the case, then because you are using the PCB manufacturer "controlled impedance" process, it turns out you can get laser drilled microvias from the top-to-first inner layer (or bottom to first inner-layer) essentially for free. Having this option makes it significantly easier to route differential traces for transceivers or LVDS, since you can drop a microvia in the two BGA pads (or right next to the pad) for the differential signal, and then route nice clean differential traces. Depending on where the LVDS signals are located, this can save you a layer in your stackup. Talk to your PCB manufacturer and see what they can provide and what the cost-differential between your options is.
Cheers,
Dave
Honored Contributor
