Restrict the aperture on the solder stencil. Slightly lift the corner edge of one BGA carrier. This action will provide HOP. Victor, -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. Sent: Tuesday, October 06, 2009 12:41 PM To: [log in to unmask] Subject: Re: [TN] BGA X-Ray Defect Detection Capabilities Apply epoxy such as red Loctite chipbonder over the board pads. The BGA sphere will not wet to the pad with the Loctite on it. My hearing aid is off. Yell all you want. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of John Burke Sent: Tuesday, October 06, 2009 12:16 PM To: [log in to unmask] Subject: Re: [TN] BGA X-Ray Defect Detection Capabilities It is very difficult to find co-planar board surface defects on Xray. The system relies on a visual interpretation for example an elongated joint profile suggests some level of co planarity issue such as component warpage - If all joints are good except one or two non wets the X-ray system may have issues resolving this. The reason is that the "pull down" of the good joints will compress the molten solder on the open joint that cannot wet to the pad and it will not look too much different from the joints around it. If you want to manufacture such a joint you could deliberately contaminate one or two BGA pads, reflow the BGA and then go take a look on the Xray system to see if you can resolve it. I am not going to tell you how to contaminate those pads (you should not have an issue) as there are people here that will yell at me.........8-) John Burke (408) 515 4992 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Leland Woodall Sent: Tuesday, October 06, 2009 8:56 AM To: [log in to unmask] Subject: [TN] BGA X-Ray Defect Detection Capabilities Everyone, I just came back from an X-ray vendor qualification trip, and of course, have a few questions for my professional peers. Both vendors experienced problems reliably detecting opens and non-wets. I really didn't expect to see this, as I thought these would be two of the most common defects seen among BGA users. We had to leave boards at both facilities so they could further develop their algorithms. We were not able to create a head-in-pillow defect, and thus, were not able to check their machines for this. They also had no sample boards that carried such an anomaly. Is this another defect that is difficult to detect, and must one utilize a 3D machine in order to find it (assuming the machine is capable of both 2D and 3D inspections, and there are no components beneath the BGA)? Are there any other caveats you might be able to provide? Our list of questions and qualification efforts were extensive, but I'm certain we missed something. I just hope whatever it was fell outside of being a critical item... Thanks in advance, Leland --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------