We run into this problem occasionally. You have pretty robust runs. Some times we see the failure at the connection between the PTH and the pad in the area of the electroless Cu. Here are something's to consider: 1. Are you cross - sectioning the actual hole that failed or one that is close? There can be differences. 2. What is the rework history (including touch - up) on the hole in question? This will again influence a specific hole and not adjacent holes. 3. You may want to try polishing down from the top down (z section). That will allow you a full 360 degree view around the PTH to pad connection. You have to be careful grinding down since the pad is only about 0.0014 inch thick if it is 1 oz Cu and it is easy to grind through. Good luck Steph Stephan Meschter [log in to unmask] Lockheed Martin Control Systems Phone :(607)770-2332 600 Main Street, MD R52F FAX :(607)770-2056 Johnson City, NY 13790-1888 MARCALL: 8 * 255-2332 > ---------- > From: Ingemar Hernefjord > (EMW)[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum.;Ingemar Hernefjord (EMW) > Sent: Friday, September 22, 2000 5:15 AM > To: [log in to unmask] > Subject: Re: [TN] FW: PCB FAILURE AFTER TEMPERATURE CYCLING > > seems as being a trouble in one or many vias. We had similar problems > many years ago. Reason was unsufficient metallisation to connect via > 'tube' with lateral copper layer. We repared with crazy but functioning > method: pressed a piece of metal in vias with open circuits, and they > worked again. Not recommended for longlife products. > > Ingemar Hernefjord > Ericsson Microwave Systems > > -----Original Message----- > From: McGlaughlin, Jeffrey A [mailto:[log in to unmask]] > Sent: den 21 september 2000 21:26 > To: [log in to unmask] > Subject: [TN] FW: PCB FAILURE AFTER TEMPERATURE CYCLING > > > > !!!HELP!!! > > > > We are experiencing a strange failure in a circuit board and I hope > > someone can point out the failure mechanism. > > The boards in question fail with trace opens when cold, heat the pin > with > > an iron and the open trace reconnects. The boards in question are 0.093" > > thick Getek, 6 layers (4 rout - 2 planes), with 0.015" trace and 0.010" > > spacing (we ain't talkin' high tech here :<) ). We have sectioned the > > holes in question and see really clean plating and pad junctions, no > smear > > or nai-heading. Any suggestions as to cause? > > > > Jeffrey A. McGlaughlin, C.I.D. > > Sr. PCB Designer > > Battelle Memorial Institute > > Columbus Ohio > > [log in to unmask] > > > > > > ############################################################## > TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d > ############################################################## > 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 > ############################################################## > > ############################################################## > TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d > ############################################################## > 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 > ############################################################## > ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d ############################################################## 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 ##############################################################