The long-term field reliability of PBGAs (presumably on FR-4) depends on a number of dimensional and material parameters as well as the severity of the use environment. Also ball height (C5 vs. high-melt solder balls) and attachment (solder-mask defined (SMD pads vs. NSMD)) play a role. The biggest impact will however come from whether or not there are solder joints underneath the die in the PBGA. For perimeter populated PBGAs there is little in terms of reliability problems, for fully populated PBGAs it will depend on the type of die-attach (rigid vs. soft). For info on accelerated testing you should follow IPC-SM-785, Guidelines for Accelerated Reliability Testing of Surface Mount Solder Attachments, and for Design for Reliability information Section 7 in J-STD-013. I will be giving a workshop at NEPCON West that deals with these issues. The workshop title is "Practical Design and Prediction Methods for Surface Mount Solder Joint Reliability". The objectives of this course are to make the participants familiar with the underlying technical issues; provide insights in the relative importance of product quality resulting from workmanship standards and process controls, and focused 'Design for Reliability;' give them an appreciation of the reliability pitfalls in the design, testing, as well as environmental stress screening (ESS) of electronic assemblies; and to present state-of-the-art, but simple to apply, tools for the 'Design for Reliability.' The attendees of the course will have an understanding of the solder behavior under load and fatigue which is necessary for the successful design, manufacture, and testing of electronic assemblies, including those newer components like BGAs, CGAs, TSOPs, etc. Processing issues to achieve the consistent solder joint quality necessary to assure reliability will also be discussed. The information presented has been included in the industry documents IPC-SM-785, 'Guidelines for Accelerated Reliability Testing of Surface Mount Solder Attachments', IPC-D-279, 'Design Guidelines for Reliable Surface Mount Technology Printed Board Assemblies', ANSI/IPC J-STD-012, 'Implementation of Flip Chip and Chip Scale Technology', and ANSI/IPC J-STD-013, 'Implementation of Ball Grid Array and Other High Density Technology'. Werner Engelmaier Engelmaier Associates, Inc. Electronic Packaging, Interconnection and Reliability Consulting 23 Gunther Street Mendham, NJ 07945 USA Phone & Fax: 201-543-2747 E-mail: [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************