Yes, there are results from studies that show the impact of 'soldermask encroachment' onto soldering pads; the most important one being the intentional soldermask defined (SMD) solder pads for BGAs. The results of accelerated thermal cycling tests show that SMD-pads can reduce the fatigue life of these solder joints by between 30% to a factor of 3--it depends on the geometry of the soldermask edge (sharp vs. rounded) and on the severity of the accelerated test. 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 subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * 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] * ***************************************************************************