I printed a PCB + got a kapton stencil made for a project I'm working on. One of the components is a BGA chip, and has vias close to the bga pads. The vias on the board don't have solder mask on them, and I'm concerned that this may lead to a short I won't be able to see. Is there something I can apply manually to minimize the chances of this, or should I not worry about it and hope that the stencil won't allow enough solder in there for a bridge?
I assume whatever it is, needs to have a high-enough melting/burning point that it won't catch fire during reflow, and also have a low - enough surface tension to not create a bump that will mess with the chip clearance?