Forum: SMT Production & Design
Thread: Reflow Profile Design
Date: June 19, 2007 07:03 PM
Author: Manuel_R
Subject: Reflow Profile Design
Hi folks. If the solder is on the BGA but is not soldered at all on the pads, then you can discard BGA solder issues, by the other hand; you might be experiencing wicking due to heat is being absorbed on component so the balls on BGA are hotter than PCB pads. I know that is hard to measure temperature on lower side and higher side of the BGA ball, maybe you can try increasing bottom side temperatures on the zones that are affecting preheat+soak (below 217�C) to try to get more temperature to pads below BGA. The lower the Cooling, the higher the intermetallic layer is resulting in brittle solder joints, if a fracture become you can observe solder in the pads and also solder in the BGA balls.
(http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=50749)