At 08:38 AM 6/5/2007, Kerry McMullen wrote: >Hi Tom, >Check the plating spec on the fab. The plating thickness in the via's >should be specified at 0.001" absolute minimum if you are going with LF >processes, regardless of the board material. > (That is what I am told). Class 2, 0.0008" minimum on PTH has been fine in our IST Pb-free qual work. Quality of drill/roughness, hole prep, electroless Cu grain/porosity, and electrolytic Cu ductility is much more important. > I >have made this change on my large 18+ layer boards, and my quality/yields >have increased, and my opens have practically diappeared. > >Kerry McMullen >Principal New Product Mfg. Engineer >LTX Corporation >825 University Avenue >Norwood, MA 02062-2643 >(T) 781-467-5468 >(C) 508-631-1832 >(F) 781-461-0993 > > > >Tom Parkinson <[log in to unmask]> >Sent by: TechNet <[log in to unmask]> >06/05/2007 10:13 AM >Please respond to >TechNet E-Mail Forum <[log in to unmask]>; Please respond to >Tom Parkinson <[log in to unmask]> > > >To >[log in to unmask] >cc > >Subject >[TN] Via Open > > > > > > >Tech Net & Designer Net > >Greetings. We are running into a situation on Lead Free processed PCBs. >Failure mode is finding open vias during unit testing (fully populated). > >Boards are Tg170, Material type EM320, 0.063" thick boards. >6 layers of 1 oz copper. ENIG 3~5u" > >Suspect vias go from top layer to bottom layer only. > >After running through reflow, we have found vias open. No visual signs of >delamination, however when ohming out the via, if we press on the via we >get >continuity - thus we suspect the vias are opening during the process. > >Anyone out there having these problems, or information concerning this >failure mode? Z-expansion failure? > > >Tom Parkinson >Quality System Manager - CIT >WinTronics, Inc. >Phone: 724-981-5770 - extension 235 > >--------------------------------------------------- >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 -----------------------------------------------------