Jason, We have indeed seen evidence of problems associated with heating surrounding components. They are particularly problematic for gull wing type parts adjacent to repaired BGA's. What happens is what IBM originally called "double reflow failures". As the adjacent component's solder joints are heated, they are not heated evenly. Some solder joints pass through liquidous prior to others. The remaining solder joints that are just below melting now have all the stresses of the part concentrated within the few remaining solder joints. The result can be a clean fracture at the weakest part of the solder joint. This is usually at the pad's intermetallic/bulk solder interface. The break is such that it is nearly undetectable. It can easily pass In Circuit Test and may not show up until in the field. That is what makes this type defect so insidious. I know "double reflow" has been mentioned in the past on the TechNet, so you might want to check the archives. Thanks, Robert Furrow Printed Wiring Board Engineer Strategic Supply Global Account Manager Supply Chain Networks Lucent Technologies 978-960-3224 [log in to unmask] -----Original Message----- From: JASON CROSS [mailto:[log in to unmask]] Sent: Monday, November 05, 2001 9:24 AM To: [log in to unmask] Subject: [TN] Effect of BGA rework to surrounding components Hello, I am hoping someone here can help with the following: recent inquiries have come up with respect to the effect of BGA rework to surrounding components. Can the heat effect to surrounding components -- the possibility (and probability) that they will reach reflow temperatures, cause problems? I am thinking of cases where some BGA balls might reach reflow temperatures and others might not on a single package at proximity to the reworked site. Another case would be where BGA packages at proximity to the reworked BGA are simply reaching high temperatures - for possibly many heat/rework cycles.. Impact to solder joint metallurgy Impact to solder joint reliability Any help or reference would be greatly appreciated. -- Jason Cross Physical Technology Engineer Alcatel Canada, Inc. (613) 784-4793 ---------------------------------------------------------------------------- ----- 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 To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL 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 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- 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 To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL 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 ---------------------------------------------------------------------------------