Dissolution rate so slow it would take forever Regards Ian Fox -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ivanoe Pedruzzi Sent: 17 January 2006 09:13 To: [log in to unmask] Subject: Re: [TN] enig bad board Richard, I took from your email: ..... With the flash gold over nickel or the ENIG plating the gold will be absorbed into the solder and you will form a solder joint to the nickel. .... The reason I asked about dissolution rate, temperature and time, is that I assumed one could have the solder join formed with copper if the Nickel is let completely to dissolve in the molten solder. Do you think this is not feasible? I value your opinion. THX, Ivan Il giorno 16/gen/06, alle ore 14:59, Stadem, Richard D. ha scritto: > Others have responded that the cost of immersion silver is usually > much less than ENIG. > But what you need to consider also is whether to use the nickel with > flash gold, standard electroless nickel/immersion gold (ENIG), or > immersion silver. > When soldering to the immersion silver finish the silver will be > absorbed into the solder and the solder joint will be formed on > copper. > With the flash gold over nickel or the ENIG plating the gold will be > absorbed into the solder and you will form a solder joint to the > nickel. > Either of the flash gold over nickel or ENIG requires plating of > nickel, and as such the process is susceptible to nickel skips, which > you have already experienced. Not much fun. > > The solder joints formed on copper will be stronger than those formed > on nickel because of nickel's much slower rate of dissolution into the > solder joint. Because of the slower dissolution rate, the assembly > requires more heat, and for a longer time, especially under the BGAs. > BGAs do an excellent job of insulating the solder spheres. > If you have BGAs or chip scale components, you will be much better off > with immersion silver finish on the PWB. If you have high impedance/ > high frequency circuitry you will also be much better off with > immersion silver. > Buy a sample of boards and qualify the assembly with the different > plating no matter which one you choose. > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Sumxplore > Sent: Friday, January 13, 2006 11:55 PM > To: [log in to unmask] > Subject: Re: [TN] enig bad board > > Looks like this is the beginning of my nightmare with more to come > after reading those valuable feedback by technetters. > > No,I haven't try immersion silver but certainly I will explore > it.Anyone can let me what is the cost differences between Immersion > silver and ENIG? > > Thank you. > > ----- Original Message ----- > From: "Lee Parker" <[log in to unmask]> > To: "'TechNet E-Mail Forum'" <[log in to unmask]>; "'sumxp'" > <[log in to unmask]> > Sent: Saturday, January 14, 2006 1:34 AM > Subject: RE: [TN] enig bad board > > >> Sumxp >> >> It is likely the thickness of the gold is inadequate and the >> underlying nickel has oxidized. I would measure the gold thickness >> (XRF) and compare it to the minimum specified. The silver color after >> erasing is most likely the nickel that is under the gold and with the > oxides removed. >> >> There are many other alternatives these days to ENIG such as >> immersion > >> silver. Have you evaluated into any of these? >> >> Best regards >> >> Lee >> >> J. L. Parker Ph.D. >> JLP Consultants LLC >> (804) 779 3389 >> >> >> Best regards >> >> Lee >> >> J. L. Parker Ph.D. >> JLP Consultants LLC >> (804) 779 3389 >> >> >> -----Original Message----- >> From: TechNet [mailto:[log in to unmask]] On Behalf Of sumxp >> Sent: Friday, January 13, 2006 10:48 AM >> To: [log in to unmask] >> Subject: [TN] enig bad board >> >> Hi, >> >> We noticed few ENIG bga pads black in color instead of gold.It turn >> silver when use eraser to remove away the black color pad.What is the >> defect mode? >> Any reliability issue?Is it advisable to continue using these pcbs? >> >> Thanks...... >> >> --------------------------------------------------- >> Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 >> ----------------------------------------------------- >> R >> >> >> -- >> No virus found in this incoming message. >> Checked by AVG Anti-Virus. >> Version: 7.0.344 / Virus Database: 267.14.17/228 - Release Date: >> 1/12/2006 >> >> > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 1.8e 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 1.8e 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 1.8e 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 -----------------------------------------------------