Phil, Dealing with the "lowest bidder" will not work on this issue! David A. Douthit Manager LoCan LLC ------------------------------ phil bavaro wrote: > We have used ENIG as our primary BGA board finish for many many, many > boards built for cellular communications without issues regarding this problem. > > We have a major PWB fabricator telling us that they cannot control what > appears to be a "black pad" problem and that we should be changing to > Entek's OSP combined with a selective gold process for our standard finish. > > I cannot say that we have never had this problem before but usually it was > more a case of unrinsed soldermask on a pad rather than corroded nickel > plating beneath the gold finish. > > I did the cross sectioning myself and took some great pictures of the > contaminated pad surfaces that were yielding when subjected to drop testing. > > I am convinced that ENIG is a solid finish but I know that it can be > susceptible to nickel wetting problems. I have three questions: > > 1) What kind of frequency are the rest of you finding "black pad" to occur > on ENIG boards? > 2) What finish do you use for high density BGA/CSP double sided boards > that have surface contact (gold) plating requirements? > 3) Are any of you using underfill to hopefully negate the solder joint > brittleness that the black pad surface inherently creates? > > --------------------------------------------------------------------------------- > 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 > To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL > To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest > 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 To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest 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 ---------------------------------------------------------------------------------