I continue to be amazed by how much experience and technical expertise there is silently monitoring TechNet. I wish to thank all the contributors for their knowledgeable inputs. The 'via heat path' and 'adjacent joint stress fractures' sounds like a model that describes what I am seeing. This model also predicts why the failures occur on QFP's with flexible leads and not on chips or components with heavy leads. I do have vias and short traces attached to those pads and intend to do a more thorough investigation of the artwork to try to predict this on future boards. Then maybe some design guidelines can be put in place (Steve). Our boards are pretty complex, 10 - 20 layers impedance control with many 1 ounce (sometimes 2 ounce) planes. Masking, aluminum heatsinks, or selective pallets would work on this particular board (and we are building a pallet now), but we run other mixed technology boards thru wave solder with double sided SMT components that may be seeing the same problem. It is a difficult problem to locate visually and at this time I am not sure how to predict it's occurrence. The first board was found in functional test. Jowan suggested running a hotter wave solder profile which I will try. I wonder if anyone has tried covering the via lands with solder mask (not tenting the via). We do that now with LPI on the top side to protect BGA's. The solder mask may provide enough thermal insulation to prevent sufficient heat flow to the QFP pads? Thanks for the help, I will let you know how we do, Jim Kittel L-3 Communications [log in to unmask] --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------