Rick, If you have good Rework machine, you can try the following: After finishing the assembly process (Without the BGA component) put solder paste on the BGA pads. You can use dispenser for that (put the maximum paste that you can) . Activate your Rework machine within new profile which enable melting the solder paste dots with the bottom heater only (selectively). During the process, make sure that the BGA component is about 1 to 2 cm above the surface of the PCB. Adjust the sequence : When the paste melt put down the BGA on board and cool down immediatly. Eli. -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Rick Thompson Sent: Thursday, April 24, 2003 6:46 PM To: [log in to unmask] Subject: [TN] 'Unique' BGA Reflow Problem We have a customer who had a custom BGA built with some additional components besides the die under the encapsulant. Unfortunately, these parts were soldered with Sn63Pb37 and the solder reflows and bridges under the encapsulant during reflow. Due to time constraints they would like to find a way to use these while they wait for new parts to be fabbed. We've tried various types of shielding, but the convection systems we have heat the entire part causing the internal reflow. Does anyone know of a focused reflow system that would allow reflowing the eutectic balls of a BGA but not apply enough heat to the top of the component to reflow the other parts? Would one of the focused IR systems (Ersa, PDR) do this? Other possibilities? Thanks in advance. Rick Thompson Sr. SMT Process Engineer SMTEK International, Inc. +1 (805) 532-2800 [log in to unmask] --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------