Steve, I'm curious: what voltage was applied across VCC-ground and for how long? Timothy Reeves ECD Circuit Board Division 13626 South Freeman Road Mulino, OR 97042 [log in to unmask] (503) 829-9108 (800) 228-8198 FAX (503) 829-5482 > ---------- > From: Stephen R. Gregory > Sent: Tuesday, February 29, 2000 7:33 > Subject: Was; Electromigration Now; Electrochemical Migration > > Hi ya'll! > > After all the replies that were sent to me, I think what I have is > electrochemical migration. I wish I had a microscope where I could take a > picture to show you, but I'll describe things again. > > There is a 6-pin header that is hand-soldered on this board. The board > failed > due to a short from VCC to Ground. We removed the header to see if we > could > spot anything beneath the plastic of the header because we didn't see > anything on the other side of the board. This header location has traces > that > run between some of the pins, and what I discovered that is if the mask > isn't > perfectly registered, the clearance area around each of the holes for the > header will expose an area on the traces that are running between them. > > On one of the boards that I looked at yesterday, I observed a "fern-like" > stucture of copper that appeared to be growing from the anular pad of the > header pins to the exposed area of the trace. I seen this at two places at > the header locations... > > I also discovered (to my dismay) that one or two of the operators have > just > been hand cleaning after soldering in this header. That since has ceased > (dammit!)... > > Again, I just want to ask, has anybody else ever seen actual copper > filaments > grow like that? From the replies I got back yesterday, most were telling > me > that I should be seeing a black, or maybe greenish mess there, and that it > would be really tough to tell if it was copper. But I swear, it clearly > has a > copper color to it.. > > Thanks again! > > -Steve Gregory- > ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################