Mornin' Inge! I have your pictures posted (it's actually a Word.doc file) at: http://stevezeva.homestead.com/files/For__TNetters.doc I must say Inge, you have more interesting images of the minute details of soldered electrical connections than just about anybody I know of, and all of us on the TechNet are lucky to have someone like you. Thank you very much Inge! Once again, I have never seen anything like this before, and I don't think many others have either... Steve Gregory -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Hernefjord Ingemar Sent: Thursday, June 14, 2007 3:19 AM To: [log in to unmask] Subject: Re: [TN] Nickel barrier and RF applications Now, Paymon's case was not a RF unit, but sort of a magnetic one, but as many are interested in microwave issues I noted some matters years ago, one connected to flux, the other to barrier layers. Sandia Labs had something called 'Low Residue Soldering Task Force'. Dr Laura Turbini and her group found a clear connection between the solder residues and increased RF loss. From her report: 'It has been shown that polyglycols and hydrobromic acid (constituents in some fluxes)diffuses into epoxy during the HASL process. Under the humid conditions of this test, these processing chemicals may change the dielectric properties of the test board, which affect the RF signal integrity.' 451 After that report and some others, we are more motivated to keep critical RF boards as clean as possible. Normally, flux residues are not an issue, but some regions of a circuit can be very sensitive to losses. The other object is rare. I'll send two pictures to Steve's Wax Cabinet. These show how NiCr leaked out from the edges of the hot RF line and deposited on the substrate. Caused severe changes in the circuit's RF properties. We have seen it just a couple of times. No explanation found how this works. Mystery among many other RF mysteries. The only thing we could verify was that the 'bleeding' NiCr coincided with the electrical field. Inge -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Paymon Sani Sent: den 13 juni 2007 17:38 To: [log in to unmask] Subject: Re: [TN] Nickel barrier and RF applications The boards are assembled with no-clean flux. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Vladimir Igoshev Sent: June 13, 2007 11:32 AM To: [log in to unmask] Subject: Re: [TN] Nickel barrier and RF applications I'm not that sure about solder wetting larger areas after the second re-flow. On ENIG it usuallyh covers pads right away (unless the re-flow is screwed). As far as flux residue is concerne, then we don't know whether they use water soluable or non-clean one. Regards, Vladimir -----Original Message----- From: TechNet To: [log in to unmask] Sent: Wed Jun 13 11:10:33 2007 Subject: Re: [TN] Nickel barrier and RF applications As I stated in my previous response to Vladimer, you are doing both. Solder flows along the traces during the first reflow, forming an IMF with the nickel, and providing a path (more conductive path) for the signal. After the second reflow, the solder joints wet out a little further, and a very small increase in the IMF also takes place. While any of these is a very small change, the cumulative effect of reflowing all of the solder joints is usually enough to create a detectable improvement in performance of the high-RF/high-impedance circuit performance. Getting rid of additional flux also helps. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Paymon Sani Sent: Wednesday, June 13, 2007 10:05 AM To: [log in to unmask] Subject: Re: [TN] Nickel barrier and RF applications This is the million $ question. The assemblies are single sided with no TH components. We simply pass them through the reflow oven for a second time without changing the reflow profile or adding paste or flux to improve the output power by 0.2 to 2 dB with majority of improvement at 0.5 dB! The question is what we are doing to the boards during the second reflow: 1- Does it evaporate some of the flux residues? 2- Does it increase the IMC thickness? The x-ray images of the before and after reflow are very similar, i.e. we are not collapsing voids or creating new voids. Paymon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Vladimir Igoshev Sent: June 13, 2007 10:39 AM To: [log in to unmask] Subject: Re: [TN] Nickel barrier and RF applications I think, there is one question to ask. If ENIG (or rather the presence of Ni) is the source of the problem, then why does 2nd reflow improves the yield? Regards, Vladimir AMD -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Paymon Sani Sent: Wednesday, June 13, 2007 10:34 AM To: [log in to unmask] Subject: Re: [TN] Nickel barrier and RF applications Thank you Steve, This sheds a lot of light on the current RF product failures at my company. As a matter of fact, my PCB supplier is applying ENIG on all copper surfaces before the mask application! Paul, thank you for initiating this trend. Cheers, Paymon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory Sent: June 13, 2007 10:23 AM To: [log in to unmask] Subject: Re: [TN] Nickel barrier and RF applications I just realized that the URL may have wrapped. Try this one: http://tinyurl.com/2vjenp This might be the same one that Inge was talking about.... Steve Gregory -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory Sent: Wednesday, June 13, 2007 9:00 AM To: [log in to unmask] Subject: Re: [TN] Nickel barrier and RF applications Here's an article: http://www.taconic-add.com/pdf/technicalarticles--effectsofsurfacefinish .pdf Steve Gregory -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Paymon Sani Sent: Wednesday, June 13, 2007 8:57 AM To: [log in to unmask] Subject: [TN] Nickel barrier and RF applications Hello John, is it documented anywhere? Paymon -----Original Message----- From: John Burke [mailto:[log in to unmask]] Sent: June 13, 2007 9:53 AM To: 'TechNet E-Mail Forum'; Paymon Sani Subject: RE: [TN] Plating The nickel in enig is not good for frequencies above 3 - 4 GHz John Burke (408) 515 4992 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Paymon Sani Sent: Wednesday, June 13, 2007 6:47 AM To: [log in to unmask] Subject: Re: [TN] Plating Hello Inge, This is very interesting! I did not make the connection between the Nickel on the PCBs and the RF application. Are there any papers that explain the sensitivity of RF applications to the Nickel barrier in ENIG PCBs? We are having trouble with a 5.8 GHz RF product right now. The assembly meets the IPC-610D requirement. However, 25% of the products fail testing. We reflow the failed assemblies for the 2nd time and 50% of them pass testing! We do not know the RC of the failures. I was suspecting the flux to be the root cause but could it be the Nickel barrier? Cheers, Paymon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Hernefjord Ingemar Sent: June 13, 2007 2:33 AM To: [log in to unmask] Subject: Re: [TN] Plating Paul, Lockheed Martin use a lot of platings. I'm not sure, but I have seen Boron as a barrier somewhere, just can't find it right now. Anyway, Lockheed as well as NASA use many special platings. Non-magnetic, guess you have a RF application that need low-loss lines. http://supplier.external.lmco.com/supplier/po_information/specpro2.htm I was myself looking for a non-magnetic finish once, and if I remember right, there is a difference between EN and EN. The acidous electroless nickel is not ferromagnetic, while alcaline electroless nickel is somewhat ferromagnetic. Borohydride electroless Nickel-Boron is probably non-magnetic too. However, you should contact your plating chemist to verify, it was many years since I mixed with this. (In earlier days, we had our own chemists, many of them had piles of knowhow, but then came the economist's era, and the chemists were kicked out) Inge -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stolar, Paul W Sent: den 12 juni 2007 23:38 To: [log in to unmask] Subject: [TN] Plating We are using nickel as a barrier metal on a PC board for the pads. Are there any other barrier metals we can use which are non-magnetic. Bare copper is not an option. Paul Stolar Materials/Reliability Engineer Manufacturing Reliability Lead Engineer Baker Atlas 713-625-5376 713-625-4949 (fax) --------------------------------------------------- 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 ----------------------------------------------------- ------------------------------------------------------------------------ ---- ----------- Confidentiality Notice This e-mail and any attachment(s) are intended for the individual or entity to which this email is addressed and may contain information that is confidential. If you are not the intended recipient or an employee or agent responsible for delivering this e-mail to the intended recipient, please be aware that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this in error, please notify the sender by telephone at 604.430.4336 or by return e-mail, and please delete or destroy all copies of this communication. Thank you! --------------------------------------------------- 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 ----------------------------------------------------- ------------------------------------------------------------------------ --------------- Confidentiality Notice This e-mail and any attachment(s) are intended for the individual or entity to which this email is addressed and may contain information that is confidential. If you are not the intended recipient or an employee or agent responsible for delivering this e-mail to the intended recipient, please be aware that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this in error, please notify the sender by telephone at 604.430.4336 or by return e-mail, and please delete or destroy all copies of this communication. Thank you! --------------------------------------------------- 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 ----------------------------------------------------- ------------------------------------------------------------------------ --------------- Confidentiality Notice This e-mail and any attachment(s) are intended for the individual or entity to which this email is addressed and may contain information that is confidential. If you are not the intended recipient or an employee or agent responsible for delivering this e-mail to the intended recipient, please be aware that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this in error, please notify the sender by telephone at 604.430.4336 or by return e-mail, and please delete or destroy all copies of this communication. Thank you! --------------------------------------------------- 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 ----------------------------------------------------- ------------------------------------------------------------------------ --------------- Confidentiality Notice This e-mail and any attachment(s) are intended for the individual or entity to which this email is addressed and may contain information that is confidential. If you are not the intended recipient or an employee or agent responsible for delivering this e-mail to the intended recipient, please be aware that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this in error, please notify the sender by telephone at 604.430.4336 or by return e-mail, and please delete or destroy all copies of this communication. Thank you! --------------------------------------------------- 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 ----------------------------------------------------- ------------------------------------------------------------------------ --------------- Confidentiality Notice This e-mail and any attachment(s) are intended for the individual or entity to which this email is addressed and may contain information that is confidential. If you are not the intended recipient or an employee or agent responsible for delivering this e-mail to the intended recipient, please be aware that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this in error, please notify the sender by telephone at 604.430.4336 or by return e-mail, and please delete or destroy all copies of this communication. Thank you! --------------------------------------------------- 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 -----------------------------------------------------