What was your PCB plated plating finish, and the paste type? Willie Duersch Projects Manager, Technical Sales Inovar, Inc. 1073 West 1700 North Logan, UT 84321 Phone: 435-792-4949 x105 Fax: 435-792-4950 Cell: 435-881-2219 (best) E-mail: [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Eric Castonguay Sent: Tuesday, October 01, 2002 4:05 PM To: [log in to unmask] Subject: [TN] Dual footprint on Stacked Memories Technet, we are using a very special component on our pcb designs that has dual footprint (fine pitch and BGA arrays). This component is made of two TSOP66 stacked in tower and have mixed terminals: gull wing leads and BGA balls. So, both TSOP are assembled together with an interposer PCB in order to make a stack. Bottom TSOP is weld to motherboard and high-temperature solder (lead-free paste) is used to weld TSOP leads to the interposer pcb. BGA solder balls are SN96/AG4 and also interfaced with motherboard. First, is anybody out there ever used this type of lead-free package before? Any success? We had many issues so far at our CM with these stacked memories: open contacts (microfractures, missing solder, poor wettability) and misaligned components. We think it is mainly because non-eutectic balls doesn't reflow with standard temperature profile (60 sec. at 183 deg. C with peak at 220 deg. C). Hence creating poor joints. Regards, Eric Castonguay Hyperchip ---------------------------------------------------------------------------- ----- 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 ---------------------------------------------------------------------------------