Look at another populated board, because the "via" may be inside the component. If the location of the solder balls is in different locations from assembly to assembly, it is a solder ball, not a via. If you have minor solder balls that do not violate the minimum electrical clearance (typically .006") and the board will be conformally coated, and is not intended for space, these are not an issue. Unless there are a lot of them, of course. If you get two or more close to each other that could possibly shift and violate the minimum electrical clearance between two non-common conductors, and you need to meet J-STD-001 Class 3, rework it. For corrective action, I would slightly reduce the apertures (10% reduction) for the component leads (for this part only), and I do a 50% reduction in the belly pad aperture, centering the paste deposit. This gets all of the printed solder paste up on the metal pads. These solder balls are from solder paste misregistration issues or if too much solder is being printed such that small amounts (paste fines) are not entirely on the pads. However, I think your solder balls in this particular case are caused by the excess paste on the component leads; it appears as if you have just the right amount of solder on the belly pads. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Sewell Sent: Monday, July 21, 2008 2:15 PM To: [log in to unmask] Subject: Re: [TN] Solder balls I was replying to Vladimir's suggestion that you might be looking at PTHs - just a quick way to check without having to get an unpopulated board or look at the gerber. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Genny Gibbard Sent: Monday, July 21, 2008 1:56 PM To: [log in to unmask] Subject: Re: [TN] Solder balls The solder balls are near the arrows. Faint grey round objects. This device does have a heat slug, and there are plated thru holes under it for heat transfer. And yes, our X-ray does allow oblique viewing. What are you suggesting we look for? -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Sewell Sent: July 21, 2008 12:53 PM To: [log in to unmask] Subject: Re: [TN] Solder balls Genny, Does your new X-Ray allow for oblique viewing? Your solderballs will stay round - vias will appear as columns. If not you can always prop up the board on one side but magnification/focus will change and the image won't be as "pretty". Mike -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Igoshev, Vladimir Sent: Monday, July 21, 2008 1:21 PM To: [log in to unmask] Subject: Re: [TN] Solder balls Hi Genny, Here is a dummy question: Why are you talking about QFN and solder balls? I guess what you see are kind of PTH for heat transfer, but not solder balls. Vladimir -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory Sent: Monday, July 21, 2008 1:54 PM To: [log in to unmask] Subject: Re: [TN] Solder balls Hi Genny! Sorry it's taken me a bit to get your picture posted, but I just got back from 2-weeks vacation and a week in Colorado going to a IPC-771/7721 instructor certification class, so I've been catching up on things this morning. But here is your picture: http://stevezeva.homestead.com/files/solderballs-QFN.jpg Myself, I wouldn't worry about them tiny solderballs. They probably aren't going anywhere, and besides if they did, they're so small what problem could it cause? Steve -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Genny Gibbard Sent: Monday, July 21, 2008 10:52 AM To: [log in to unmask] Subject: [TN] Solder balls Have you ever gotten a much better analytical tool available to you, and have it cause major panic due to what you can see now that you never saw before? We got a major fancy dancy brand new X-Ray. Now we see things like the attached picture. Steve, could I trouble you to post it for me? <<solderballs-QFN.jpg>> Our old X-Ray would have never seen this. Would you fail these solder balls? It is a QFN, 0.5mm pitch, 0.3mm pad width with a heat slug. I think trying to replace this device by hand would cause more trouble than we see right now. Genny --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------