Werner, What I am trying to say is that issues of ground plane configuration will probably not lead to a reliability issue directly, unless they cause issues during reflow of the BGA. But if the ground pour is done using soldermask-defined pads, the soldermask-defined pads can lead to premature failure of the SJ. My understanding (gained from a direct question I asked you in your class) was that the soldermask can constrict the solder during CTE expansion and contraction. Did I not understand you correctly? -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /* Sent: Thursday, September 17, 2009 12:32 PM To: [log in to unmask] Subject: Re: [TN] fractured SJs due to soldermask compression Hi Chris, First, never heard of "fractured SJs due to soldermask compression during cyclic operation"—solder mask is much too soft and too thin; now, if you talk encapsulants that is a different story. Second, "all of the other issues pale in the face of fractured SJs due to soldermask compression during cyclic operation"—even if it were an issue, a failure is a failure is a failure—'nough said. Werner -----Original Message----- From: Chris Ball <[log in to unmask]> To: [log in to unmask] Sent: Thu, Sep 17, 2009 1:07 pm Subject: [TN] fractured SJs due to soldermask compression Hello, Starting a new branch here. "All of the other issues pale in the face of fractured SJs due to soldermask compression during cyclic operation." Is this concern specifically for BGAs, or the same for any soldermask defined pad, even including selectively waved through-hole (PbFree)? Thanks, -Chris This e-mail message is intended only for the use of the intended recipient(s). The information contained therein may be confidential or privileged, and its disclosure or reproduction is strictly prohibited. If you are not the intended recipient, please return it immediately to its sender at the above address and destroy it. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily20halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------