Hi, Copper Oxide may not be as big a problem as Copper chlorides especially if a bias voltage is applied and some liquid moisture is present. You would need to evaluate the susceptibilty of your assembly to salt and moisture. This is probably only a concern if you are in a harsh environment. You can try a real easy experiment by putting a 5-10V bias between two adjacent copper conductors and place a drop of salt between them and let it sit for a while and watch what happens. Steph ********************************************************* Stephan Meschter [log in to unmask] Lockheed Martin Control Systems Phone :(607)770-2332 600 Main Street, MD R52F FAX :(607)770-2056 Johnson City, NY 13790-1888 MARCALL: 8 * 255-2332 ********************************************************* > ---------- > From: Michael Carano[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum.;Michael Carano > Sent: Wednesday, May 27, 1998 12:11 AM > To: [log in to unmask] > Subject: Re: [TN] HASL alternative.Exposed copper > > SteveZeva wrote: > > > > Hi Nicolas! > > > > As far as the exposed copper that results from an OSP process, > there > > isn't an issue as far as I know. Yes the copper will oxidize, but from > the > > little bit I know about metallurgy, it's my understanding is that the > copper > > will be coated with a layer of oxidation, and then it slows down > dramatically. > > For a illustration of that just think about some of the copper water > lines in > > old houses, the copper telephone lines exposed to the elements for years > and > > years...that shows that it takes quite a while for copper to > deteriorate. > > > > Somebody correct me if I'm wrong about this, but the exposed copper > > problems that are defects usually have something to do with the exposed > copper > > being an indicator of some other problem, not the fact that the copper > itself > > is exposed. Oxidation of the copper is normally only a problem when > trying to > > solder to it... > > > > C-ya, > > > > -Steve Gregory- > > > > ################################################################ > > TechNet E-Mail Forum provided as a free service by IPC using LISTSERV > 1.8c > > ################################################################ > > To subscribe/unsubscribe, send a message to [log in to unmask] with > following text in the body: > > To subscribe: SUBSCRIBE TechNet <your full name> > > To unsubscribe: SIGNOFF TechNet > > ################################################################ > > Please visit IPC web site (http://jefry.ipc.org/forum.htm) for > additional information. > > For technical support contact Hugo Scaramuzza at [log in to unmask] or > 847-509-9700 ext.312 > > ################################################################Hi > Nicolas, > I have come across this question of the exposed copper with respect to > OSP's. While solder paste spreading will vary from paste to paste and OSP > to OSP, no one has ever(to my knowledge) determined that the exposed > copper caused a long term reliability problem. Maybe Jack Crawford at > the IPC can help with this one. > > Best regards, > > ################################################################ > TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c > ################################################################ > To subscribe/unsubscribe, send a message to [log in to unmask] with > following text in the body: > To subscribe: SUBSCRIBE TechNet <your full name> > To unsubscribe: SIGNOFF TechNet > ################################################################ > Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional > information. > For technical support contact Hugo Scaramuzza at [log in to unmask] or > 847-509-9700 ext.312 > ################################################################ > ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################