Jim, We have utilized immersion silver as a PWB surface finish on a large quantity of boards for the past few years. Our experience has been excellent and it is now the preferred finish at some of our manufacturing locations. George Wenger of our research center and I submitted a paper which he presented that detailed our qualification and experience (up to that point) at the September 1999 IPC Surface Finish Forum. Since then we have qualified several PWB shops for this use and have qualified another chemistry vendor's process. We have found if stored properly, the finish retains excellent solderability for over a year. It handles multiple thermal excursions well and has superior hole fill characteristics compared to OSP's. We did see a few start-up issues with our initial board vendor, but since then things have gone smoothly. To date, I have seen two relatively minor assembly issues. The first is that the surface will darken if exposed to sulfur. The solderability remains good, but cosmetically it was very noticeable. This became evident at one location when after the first side surface mount operation, boards were placed onto an ESD mat that had a high sulfur content. Switching to a new type of mat resolved this issue. The second issue is pin contact at ICT. If you are not wave soldering or if you selectively wave solder, then some of the test pins may contact silver coated pads. If your test fixtures are set up to handle OSP coated boards I would expect no issues, but if they have only tested to solder previously, there might be a need to either change probe types or optimize the fixture. As far as cost is concerned I would expect it to be between the cost of an OSP coated board and that of a HASL finish. If you would like further information please contact me. Thanks, Robert Furrow SMT Process Engineer Lucent Technologies 978-960-3224 [log in to unmask] > -----Original Message----- > From: Jim McMurry [SMTP:[log in to unmask]] > Sent: Monday, November 06, 2000 9:05 AM > To: [log in to unmask] > Subject: [TN] IMMERSION SILVER SURFACE FINISH > > Jim McMurry@PATAPSCO > 11/06/2000 09:05 AM > > I am interested in hereing from anyone who may be using or may have used > immersion silver finish on production or prototype pcb's. I would like to > know > the good and bad sides of this finish. If there are any information > resources > available on the subject. Are there any cost comparisons? > > Thank you all for your time and response. > > -------------------------------------------------------------------------- > ------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > Search previous postings at: www.ipc.org > On-Line Resources & Databases > > E-mail Archives > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for > additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > -------------------------------------------------------------------------- > ------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------