Forum: SMT Production & Design
Thread: Nitrogen gas and Tombstone defect
Date: November 21, 2011 10:51 AM
Author: ScottE
Subject: Nitrogen gas and Tombstone defect
I've never seen a good article with a definitive explanation - just speculation that the increased wetting forces due to nitrogen result in increased tombstones. My own experience is that nitrogen is a very minor contributor to tombstones and can pretty safely be ignored. Much more important are proper pad design (don't make the pads too long), print & placement accuracy (especially bad is print offset in one direction and placement in the other), and reflow profile (short profiles worse than longer ones).
(http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=65500)