Hi Hans, In the process of mounting flip chips or chip scale packages to PCBs, there's a need to fill the gap between the chip and the board with an adhesive to minimise the CTE mismatch between the board and the die. this is known as underfilling. and the reason i'm asking is because reliability of the solder joints is compromised when there is a lot of outgassing from the board into the adhesive material while curing. If there was pretreating of the boards in an oven, this problem would be greatly reduced. thanks Hann Hans Hinners <[log in to unmask]> on 12/05/2000 12:00:15 PM To: "'TechNet E-Mail Forum.'" <[log in to unmask]> Hann Pang/US-Corporate/3M/US@3M-Corporate cc: Subject: RE: [TN] Query: industry standard for pretreating PWB/PCB before underfilling? Hann, Help me out here. By underfill do you mean an application of an RTV or is it some other process? Hans ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Hans M. Hinners Process Engineer Toppan Electronics, Inc. 770 Miramar Road San Diego, CA 92126 (858) 695 - 2222 ext. 241 (858) 695 - 6823 fax [log in to unmask] -----Original Message----- From: Hann Pang [mailto:[log in to unmask]] Sent: Tuesday, December 05, 2000 9:27 AM To: [log in to unmask] Subject: [TN] Query: industry standard for pretreating PWB/PCB before underfilling? Hi Can someone help me with the question?? Thank you very much. I'm posting the above question as a technical marketer for 3M. We're currently working on underfills and the question is posed in consideration of the outgassing of the PCBs. If there is'nt a standard, then the next question is; typically, what are the pretreating conditions if there is any pretreating at all? Thanks and regards, Hann Pang Technical Markerter ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------