Sometimes, you can get by with vias in your pads. Sometimes, but not very often. I wrote about this a while back here. The thing is, I was talking about big pads - like QFN or QFP thermal pads and stuff like that. We never like to see it and it’s always a manufacturing risk at some level, but as described in the earlier post, sometimes you can just roll with it.

Pretty much never with a BGA pad though. The pic on the left shows just about aworst-case scenario. Very big. Very bad. Relatively very big holes anyway. This is for a .5mm pitch Bluetooth module BGA.

The photo above is pretty hilarious.