BGA via-in-pad; Vias in the Footprint, or in the PCB Editor?

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Hello,

I wish to use a BGA (0.65mm pitch, 25 connections) for a hobby project. I’ve not done this before. I would like to try via-in-pad rather than dogbone, because the PCB manufacturer offers filled V-I-P at low cost, and it would be worth experimenting.

My question is, should I design the BGA footprint using SMD pads (which is what the Create Footprint feature does) and then later, when in the PCB Editor, drop vias onto those pads?

Or, should I create a BGA footprint actually composed of through-hole pads? Apologies if this is a silly question. I’m just very new to design with BGAs!

Many thanks.

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i’d do this, so my pcb library stays small, but i think that you can do the other way if you want to minimize the clicks in case you plan to reuse the footprint in many other projects.

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However, remember that if you add the plated holes to the footprint, it becomes less versatile and reusable. For example the whole backside will be reserved for the holes. The footprint may not be so useful for multilayer boards. Via size is fixed. You could of course edit the footprint when used for different projects, but does it mean more or less work?

The situation is the same with many standard IC footprints in the KiCad library. They have two versions: with and without thermal vias.

There’s no one optimal solution.

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I would always do VIP in the board, not the footprint. The reason is that I almost never need the same pads to have vias in every design. Some pads may not be used at all; some may be able to fan out on the same layer as the BGA in some situations but not others, etc. It is easiest to make this decision while doing board layout, not when designing a footprint.

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Indeed. Using all tht pads would take up a lot of PCB space on all inner layers under the BGA. This option just does not make much sense.

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Thanks for the feedback everyone!
I should have clarified, this isn’t an FPGA, so the pads which would need vias would be fairly well defined and unlikely to change as I design the routing out strategy for that BGA device for the 4-layer board it is intended to be used on. Nevertheless, the resounding feedback is that the via’s should be part of the board layout, not the footprint, so I’ll proceed with that. Thanks again for all the excellent advice. Looking forward to trying this out.

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