Here are some links referencing solder mask defined/non-solder mask defined (SMD/NSMD) pad reliability. Generally, these references report that NSMD designs provide more reliable solder joints than the SMD approach. www.intel.com/design/flash/packdata/csp/download.htm www.mot-sps.com/cgi-bin/get.pl?/books/apnotes/pdf/an1231*.pdf www.amkor.com/customer_center/assembly_and_test/white_papers/index.htm FYI, our CCA designs that use BGA have NSMD pads. We have used BGA technology in our products (telecom, broadband, high speed network access) for approximately four (4) years now. Our products are typically installed in controlled environment settings (commercial, residential, telco central office, etc.) and do not experience the extremes of automotive or aerospace applications. Thanks to all TechNet contributors! I've used this resource for some time and find the discussions most relevant. I'm glad that I have the opportunity to contribute to this forum! P.S. - I'm attending the SMTA International 2000 Conference in Chicago from 25-28 September. I'm focusing primarily on CSP, alternative PWB finishes, BGA rework, and the double-sided reflow process (manufacturing and test). If anyone else is attending and would like to trade "war stories" at this time, please contact me via email. ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################