>Moonman stated that Werner Engelmaier wrote the book on CGAs. A: Only regarding their reliability. >Can you explain any problems in the use of CGAs? A: Manufacture and assembly are more difficult; CGAs do not self-center during reflow; they are more susceptible to damage from vibration and mechanical shock. >In manufacturing, how reproducible is the assembly using CGAs? A: With proper care, no real problem. >What solder is best to use in soldering the CGA to a ceramic device? A: Eutectic or near-eutectic Sn/Pb. >Papers I have read state that the thermal cycling longevity of solder joints to >ceramic devices with 100 mil CGA is 45 times longer than that of the equivalent BGA. >Is this correct? A: One cannot make a blanket statement like that. Depending on the details increases in fatigue life are possible, but you certainly would have to have a proper 'Design for Reliability' to achieve this. >Is there a leaded solution to the problem of assembling >ceramics to Glass/Epoxy for LCCs that would be better? A: Yes, there are clip-leads that work exceedingly well; see my paper: Engelmaier, W., and A. I. Attarwala, "Surface-Mount Attachment Reliability of Clip-Leaded Ceramic Chip Carriers on FR-4 Circuit Boards," IEEE Trans. Components, Hybrids, and Manufacturing Technology, Vol. CHMT-12, No. 2, June 1989, pp. 284-296. 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 1.8e 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------