Electronic – Insulating a via during reflow

pcbreflowsoldering

I have a PCB that I'm sending off for assembly, which includes going through a reflow oven. The last batch had a problem because the solder mask on some PCBs does not completely insulate a via that is underneath a metal connector, resulting in a short. What can I safely use (that will withstand reflow temperatures) to paint or insulate the via to prevent the short?

Best Answer

You want to "tent" your vias. This means changing your DRC such that vias under a certain drill size will have solder mask extend over them.

If you are using Eagle, this is accomplished by changing the "Limit" value on the Masks tab of the DRC. The limit specifies what size drill hit that the solder mask should cover up to.

Check out the tutorial from Sparkfun on better PCB's.