Hello Seppo, Underfill will definitely "save" you from having cracked joints (particularly due to drops), but it's a "painful" procedure. Regards, Vladimir Vladimir Igoshev Research in Motion -----Original Message----- From: Seppo Saario [mailto:[log in to unmask]] Sent: Thursday, December 18, 2003 8:49 PM To: [log in to unmask] Subject: [TN] BGA Underfill comments/recommendations Dear All, I am doing some checking into the effectiveness of BGA underfill on mobile handsets. Typically handset boards have 3-4 BGA's (0.5 to 0.8mm pitch) and have seen handsets with and without underfill. PCB thickness is 0.8mm Has anyone seen any studies, or have any comments on the reliability of BGA joints wrt underfill. Also, any comments on what typically recommended underfill compounds are is also appreciated. Thanks in advance! - and wishing you all a Merry Christmas and a Happy New Year !. -- Seppo Saario Voxson Ltd., Core Technologies - Hardware Design Engineer Tel +61-7-3268-0745 ; Fax +61-7-3878-1370 -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: Friday, 19 December 2003 10:20 AM To: [log in to unmask] Subject: Re: [TN] Need your opinion I would agree with the shearing rather than routing of the edges. With the severe crazing that extends to the ball area, it is a realiability issue. The cracking of the solder mask is a real concern and indication that the edges are suspect. Susan Mansilla Robisan Lab --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- Main Switch: +61 7 3868 1277 Fax: +61 7 3868 1370 Home Page: www.voxson.com Local Time : GMT + 10 hours Disclaimer - This e-mail is intended only for the addressee(s) named above. This e-mail may contain confidential or privileged information. No confidentiality or privilege is waived or lost by any mis-transmission. If you are not a named addressee, or the person responsible for delivering the message to the named addressee, please telephone the sender immediately on the number above and delete the message. You must not disclose, copy or rely on any part of this correspondence if you are not the intended recipient. --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------