Steve, Now that you have probably identified the root cause of the bumps, going back to your original question, "should I worry about these bumps?" I would hazard a guess that you should worry about them. It depends though, on whether there will be problems if the components are not sitting flat on the lands. There will be a loss of surface contact on the components that have exposed pads on the bottom that are meant to be soldered flat for grounding and cooling purposes. And it appears that many of the chip caps/resistors will not be sitting on a flat pad either, which could contribute to tombstoning, skewing, and other problems. If there are any via-in-pad BGA pads they will most likely have a multitude of voids and other issues, and so on. I do not know enough about the rest of the board to tell you if this is going to be a problem or not, but these are things you may wish to consider. On the other hand there should be less entrapped flux under the parts. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory Sent: Wednesday, September 14, 2005 9:57 AM To: [log in to unmask] Subject: Re: [TN] [OT]...sorta RE: [TN] raised vias...I did a "Okie" cross-section You're right Dewey. Geeze, always correcting me... I shoulda' said; I did a "Okie-dokie" Okie cross-section, huh? Speaking of which, I went back it at again this morning for a bit. Went deeper and deeper, and the width of the hole in the via did not change much, which tells me that I was pretty much in the center of the via....and as was commented earlier, they did a heck of a job plating the walls of the vias...that's some thick walls of copper. I got to a point where I could start seeing the back wall of the hole, because some of the resin was coming out of the hole from the gentle scraping I was doing with the exacto knife, and yes, now I believe that is pre-preg resin coming up through the blind via hole during lamination to the thick copper core. You can see my latest image at: http://www.stevezeva.homestead.com/files/Cross_Section.jpg This is a image that was taken from our SmartScope Flash system at somewhere around 200 magnification. Now comes the big question, are the bumps a reliability issue? I did see some open/insufficient solder defects in the first build of these boards. We touched things up for the most part, before I knew what was causing the defects. I can compensate for the insufficient solder problems probably by getting a thicker stencil, so should I worry about these bumps? -Steve- |---------+-------------------------------> | | "Whittaker, Dewey | | | (AZ75)" | | | <Dewey.Whittaker@HON| | | EYWELL.COM> | | | Sent by: TechNet | | | <[log in to unmask]> | | | | | | | | | 09/14/2005 08:38 AM | | | Please respond to | | | TechNet E-Mail Forum| | | <[log in to unmask]>; | | | Please respond to | | | "Whittaker, Dewey | | | (AZ75)" | | | <Dewey.Whittaker@HON| | | EYWELL.COM> | | | | |---------+-------------------------------> >----------------------------------------------------------------------- ---------------------------------------| | | | To: [log in to unmask]@SMTP@Exchange | | cc: (bcc: Stephen R Gregory/LABARGE) | | Subject: Re: [TN] [OT] RE: [TN] raised vias...I did a "Okie" cross-section | >----------------------------------------------------------------------- ---------------------------------------| I is a half-way measure. Doakie completes the affirmation. Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Craig Cullum Sent: Wednesday, September 14, 2005 5:55 AM To: [log in to unmask] Subject: [TN] [OT] RE: [TN] raised vias...I did a "Okie" cross-section OK, could someone explain to me what "Okie" means please? TIA --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- __________________________________________________________________ This message may contain information that is privileged and confidential to LaBarge, Inc. It is for use only by the individual or entity named above. If you are not the intended recipient, you may not copy, use or deliver this message to anyone. In such event, you should destroy the message and kindly notify the sender by reply e-mail. --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------