Graham, Is the " VIBRATION " test within the expected evaluation or do you have a " MARGINAL " BGA joint, interface, to begin with. What do cross section of the failing BGA look like especially the Intermetallic Compound, IMC, region. Is this region smooth or evidence of some large nodules at 1000x after copper etchant application. Are the failing BGA at random or location sensitive. How many REFLOW temperatures did this PCBA received. BGA are ROBUST interfaces. victor, -----Original Message----- From: Graham Collins [mailto:[log in to unmask]] Sent: Tuesday, September 10, 2002 11:51 AM To: [log in to unmask] Subject: Re: [TN] BGA Under fill Victor 1) TCE is compatable with the board and bga. Not sure why that would influence an answer concerning voids... 2) main purpose is to provide support to solder joints (vibration resistance). 3) I "hope" to fill the entire gap (100% fill) - but realistically some voids are likely to occur. What % of voids are reasonable and acceptable is the question. 4&5) Loctite 3568 is applied to 2 sides of the component in accordance with the manufacturer's instructions, the board and part are preheated to 100C and following application the cure is 15 minutes at 150C. regards, Graham Collins Process Engineer, Northrop Grumman Canada Atlantic Facility (902) 873-2000 ext 6215 >>> [log in to unmask] 09/10/02 10:17AM >>> Graham, Have you considered the thermal properties, TCE, of the Locite 3568 product. Is this compatible with the TCE of the PCB and device carrier. What is the main PURPOSE of the proposed UNDER FILL application? How far into the device carrier to you HOPE to FILL? Will the LOCITE have to be cured? Is the PCB Pre Heated? Victor, -----Original Message----- From: Graham Collins [mailto:[log in to unmask]] Sent: Tuesday, September 10, 2002 6:09 AM To: [log in to unmask] Subject: [TN] BGA Underfill Good day TechNet! A question for the BGA / Underfill guru's out there (hopefully we have some of those online). Using a capillary flow underfill on a BGA, say a .050 pitch 26x26 array, what is a reasonable result to expect with respect to voiding? Should this process result in no voids, some voids, lots of voids? Given the size of this part (1.38" square), is it reasonable to expect a void free underfill? The particulars: I'm using Loctite 3568 underfill, applied using a syringe along two edges (L pattern). Product is on a hotplate at 100C. Thanks all! regards Graham Collins Process Engineer, Northrop Grumman Atlantic Facility of Litton Systems Canada (902) 873-2000 ext 6215 ---------------------------------------------------------------------------- ----- 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 ---------------------------------------------------------------------------- ----- ---------------------------------------------------------------------------- ----- 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 ---------------------------------------------------------------------------------