We have done BGAs for a while. About a year ago we were struck with black pad. Firstly, I can't help wondering if there is some connection, directly or indirectly, with the RoHS-mandated changes. ENIG has been around for a while, but was not in as prevalent usage. And the specs surrounding how to do it reliably seem to be in a state of flux. Secondly, it preferentially attacks specific pads repeatedly on multiple boards, while rarely attacking adjacent pads of the same size and shape on the same boards. This implies a dependency on how the board is designed, which means I want to know how to make it stop if I can. We had two different PCB designs in the same product using the same layer stackup, layer thicknesses, trace widths and spacing, BGA pitch, plane structure, processes, etc. They were both fabricated by the same fabrication house and assembled by the same assembly house in the same general timeframe. Black Pad hit multiple pads on nearly every board of one design over both runs, but never hit any pads of any board of the other design over both runs. I find that interesting.
I wonder what other problems will shake out in the next couple years. Jeff ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>; <[email protected]> Sent: Monday, August 13, 2007 1:56 PM Subject: RE: [PEDA] Black Pad > So... what do you find so interesting about the issue, Jeff? > > Has there been a technical detail that's been found recently to bring > the question into more focus for board houses and/or their customers? Or > perhaps it's something else? > > Regards, > > aj > >>-----Original Message----- >>From: [EMAIL PROTECTED] >>[mailto:[EMAIL PROTECTED] On Behalf Of Jeff Condit >>Sent: Sunday, August 12, 2007 8:08 PM >>To: Protel EDA Forum >>Subject: [PEDA] Black Pad >> >>Are you all familiar with "Black Pad"? I've been looking into >>it and its interesting. >> >>Jeff >> >>____________________________________________________________ >>You are subscribed to the PEDA discussion forum >> >>To Post messages: >>mailto:[email protected] >> >>Unsubscribe and Other Options: >>http://techservinc.com/mailman/listinfo/peda_techservinc.com >> >>Browse or Search Old Archives (2001-2004): >>http://www.mail-archive.com/[EMAIL PROTECTED] >> >>Browse or Search Current Archives (2004-Current): >>http://www.mail-archive.com/[email protected] >> >> > > > This e-mail transmission and its attachments may contain information from > Avtron Manufacturing, Inc. that is proprietary, privileged and/or > confidential and is intended exclusively for the person(s) to whom it is > addressed. Any use, copying, retention or disclosure by any person other > than the intended recipient or the intended recipient's designees is > strictly prohibited. If you have received this message in error, please > notify the sender immediately by return e-mail and delete all copies. > > > > -- > No virus found in this incoming message. > Checked by AVG. > Version: 7.5.483 / Virus Database: 269.11.17/951 - Release Date: 8/13/2007 > 10:15 AM > > ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[EMAIL PROTECTED] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
