John, Isn't the micro BGA designed to have the stress' relieved on the device/package itself? Doesn't the the (small) size help with this also? (PPM X and Y expansion) Check out the Tessera website at http://www.tessera.com/ I'm sure you'll find out the answer there. Groovy -----Original Message----- From: John Harris [mailto:[log in to unmask]] Sent: Monday, July 19, 1999 06:38 PM To: [log in to unmask] Subject: [TN] Underfill on Micro BGA Micro BGA Do Micro BGA's require underfill or encapsulation to ensure the solder joints aren't stressed during the life of the product. Any thoughts or recomendations would be appreciated! Thanks ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## 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 Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## 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 Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################