Please copy me when you send the pictures. I never realized that BGA heatsinks could cause these issues. I figures the experts that designed BGA heatsinks made sure they wouldn't decrease reliability. As a contract assembler we would assume the failed BGA was from either the BGA mfg or something in our process and therefore repair as the board under warrantee. -------------- Original message -------------- From: Victor Hernandez <[log in to unmask]> > Werner, > > Could I also get copied on the moiré pictures? Supported data as such is > always interesting. > > vic. > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner engelmaier > Sent: Friday, December 05, 2008 2:11 PM > To: [log in to unmask] > Subject: Re: [TN] ??: Re: [TN] BGA soldering open issue > > > Hi Arnaud, > A BGA with an attached heatsink is causing the BGA to be thermally > unsymmetrical--and you get warpage by the 'bimetallic strip' effect. > I show some nice shadow moire pictures [courtesy Advanced Semiconductor > Engineering Inc.] showing 9 mils of warpage fro 20 to 240°C in my workshops. > > Werner > > > > > > > > -----Original Message----- > From: Arnaud Grivon > To: Werner engelmaier > Sent: Fri, 5 Dec 2008 9:21 am > Subject: Re: [TN] 答复: Re: [TN] BGA soldering open issue > > > > > > > > > > Hello Werner, > > > Could you please elaborate on your posting stating that BGAs with > heatsinks are more prone to warpage during assembly? > > Are you thinking of cavity down BGA (such as SBGA), FC-PBGA, or...? > > Would you have any publication/article to share? > > I thank you in advance for your support. > > Best regards, > > > Arnaud Grivon > > > Werner engelmaier a écrit : > > > Nee hao Hechong, > > > BGAs with heatsinks have been shown to warp and thus loading the SJs in > tension. > > > > > > Werner > > > > > > > > > > > > > > > > > > > > > > -----Original Message----- > > > From: Cong He > > > To: [log in to unmask] > > > Sent: Thu, 4 Dec 2008 10:08 pm > > > Subject: [TN] 答复: Re: [TN] BGA soldering open issue > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > surface fin > ish is hasl. > > > > > after analysed parts of the board, we found some balls of the bga rupture. > > > Could it be the material of the ball(BGA) cause the problem? > > > > > > by the way, there is a heatsink which is double size lager than the chip > > stick on it without other fixture. > > > will the heatsink be the reason? > > > > > > > > > > > > > > > > > > > > > Hechong > > > > > > > > > > > > > > > > > > "Wenger, George M." > > 发件人: TechNet > > > 2008-12-05 10:57 > > > 请答复 给 > > > TechNet E-Mail Forum ; 请答复 给 > > > "Wenger, George M." > > > > > > > > > 收件人 > > > [log in to unmask] > > > 抄送 > > > > > > 主题 > > > Re: [TN] BGA soldering open issue > > > > > > > > > > > > > > > > > > > > > What is the surface finish on your PCBA? > > > > > > > > > > > > Necong, > > > > > > What is the surface finish on your PCBA? > > > > > > Regards, > > > George > > > George M. Wenger > > > Andrew Wireless Solutions > > > Senior Principal FMA / Reliability Engineer > > > 40 Technology Drive, Warren, NJ 07059 > > > (908) 546-4531 [Office] (732) 309-8964 [Cell] > > > [log in to unmask] > > > > > > > > -----Original Message----- > > > From > : TechNet [mailto:[log in to unmask]] On Behalf Of Cong He > > > Sent: Thursday, December 04, 2008 9:09 PM > > > To: [log in to unmask] > > > Subject: [TN] BGA soldering ope > > > n issue > > > > > > dear all: > > > > > > I am facing a problem of bga soldering. > > > > > > when the board have just soldered ,it pass all test. > > > But after sometime, maybe for a few weeks, > > > some of the bga balls opened. the function became normal if i press the > > chip on the top side. > > > > > > It seems that the pcb didn't warp much,it seems even no warp at all. > > > Does any of you know why? And how to improve? > > > > > > > > > > > > > > > > > > > > Hechong > > > > > > --------------------------------------------------- > > > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > > > 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 sasako@ > ipc.org or 847-615-7100 > > > ext.2815 > > > ----------------------------------------------------- > > > > > > > > > No virus found in this incoming message. > > > Checked by AVG - http://www.avg.com > > Version: 8.0.176 / Virus Database: 270.9.13/1828 - Release Date: > > > 12/4/2008 8:05 AM > > > > -------------------------------------------------------------------------------- > ---------------- > > > This message is for the designated recipient only and may > > > contain privileged, proprietary, or otherwise private information. > > If you have received it in error, please notif > > > y the sender > > > immediately and delete the original. Any unauthorized use of > > > this email is prohibited. > > > > -------------------------------------------------------------------------------- > ---------------- > > > [mf2] > > > > > > > > > --------------------------------------------------- > > > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > > > 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 contac > t Keach Sasamori at [log in to unmask] or > > 847-615-7100 ext.2815 > > > ----------------------------------------------------- > > > > > > > > > > > > > > > > > > > > > > > > > > --------------------------------------------------- > > > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > > > 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 > 847-615-7100 ext.2815 > > > ----------------------------------------------------- > > > > > > > > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > 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 > 847-615-7100 ext.2815 > ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 -----------------------------------------------------