Hi Mickey, Both of your quotes can be right, DEPENDING... Everything else being equal you are likely to get the best results with the pads on the PCB matching the pads on the BGA. Reducing the pad size, can indeed increase solder joint height (=longer life) if you do not decrease the solder volume, but you can also get more of a stress concentration geometry (=shorter life). However, these differences will be small (they are more pronounced for accelerated testing results than for product life in service). What you actually will get will depend on solder volume, BGA weight, number of solder balls, solder paste vs. flux only, SMD vs. NSMD, near-eutectic vs. high-melt solder balls, etc. There are much more significant parameters affecting solder joint reliability, PBGA and uBGA construction being one of them, service environment another. Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine Run Ormond Beach, FL 32174 USA Phone: 904-437-8747, Fax: 904-437-8737 E-mail: [log in to unmask], Website: www.engelmaier.com --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------