Well for the record I thought that the colr choice was really cool............. Thought about sending out a series of screensaver images Inge?? John...........8-) -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Hfjord Sent: Tuesday, September 12, 2006 10:42 AM To: [log in to unmask] Subject: Re: [TN] PbCO3 33.5 % NTC all SEM manufacturers have pseudocolouration programs Inge ----- Original Message ----- From: "Joyce Koo" <[log in to unmask]> To: <[log in to unmask]> Sent: Tuesday, September 12, 2006 3:24 PM Subject: Re: [TN] PbCO3 33.5 % NTC > wow! what is the brand? how could you get color? excellent...jk > > abcd > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]]On Behalf Of Steve Gregory > Sent: Tuesday, September 12, 2006 8:35 AM > To: [log in to unmask] > Subject: Re: [TN] PbCO3 33.5 % NTC > > > Morning Inge! > > I have your pictures posted. I have never seen such stunning images! You > have opened my eyes to a strange new world! This looks like some bizzare > alien landscape. Even if I don't know exactly what they mean, I really > enjoy looking at them! Here they are for everyone to see: > > http://stevezeva.homestead.com/files/daniel121b.jpg > > http://stevezeva.homestead.com/files/daniel131b.jpg > > http://stevezeva.homestead.com/files/daniel141b.jpg > > -Steve Gregory- > > >> About PbCO3, we used a special tool to take samples from our balls. > The following SEM/EDAX showed, with 95% confidence, that something > erects from the > balls: Lead whiskers ! Starts with tiny, less than 0.1 > um wide, whiskers. They seem to grow in all three coordinates, until > several um wide and many um > long. Close SEM images show how they > protrude through the ball surface, which is >95% Lead. Looks like a > seal's periscope penetrating the polar ice > with Rock Hudson as > captain. > >> jk proposed, that the balls may be plated, and that this plating > creates mechanical tensions, which starts the whisker growth. Anyone > heard of such > overplating for BGAs? Wafer bumps, yes, but not heard > of such treatment for BGAs. > >> I'll send scary pics to Stefanos Gregorius. > >> Inge > > > > >> ----- Original Message ----- >> From: "P. Langeveld" <[log in to unmask]> >> To: <[log in to unmask]> >> Sent: Monday, September 04, 2006 8:49 PM >> Subject: Re: [TN] PbCO3 > > >> That guy is me: Peer Langeveld, Consultant Soft Soldering Processes, >> living at 5502 VH 8 The Netherlands, pupil of R.J. Klein Wassink, with >> 26 years of experience in soft soldering processes whereof 10 years in > >> lead-free soldering (IDEALS project). >> >> By the way, CBGA's were not known in the early eighties of the last >> century. >> >> I just mentioned lead whisker growth as an option. A picture is known >> (Klein Wassink, page 295) and the needle form is simular to the SEM >> photo, combined with the EDAX analysis that only shows lead. And >> whiskers grow very fast under stress conditions. >> >> >> 2006/9/4, Ingemar Hernefjord (KC/EMW) > <[log in to unmask]>: >>> Triple Hmmm! >>> >>> I used Gilette, which is little rough, but it works fine: dropped a >>> board in LN2. When at -196 knocked the backside of the board, and the > >>> CBGA jumped off. Could then study the cleanliness. No flux residues >>> or whatsoever. >>> Yepp, Vigon is indeed very active, but why does the phenomenon appear > >>> only on CBGAs? We have other BGAs on the board, and these have never >>> shown such growths. >>> >>> I'm attempted to go on quite another track for a while. One guy >>> proposed whisker growth. And, when you look at the SEM image, you >>> find something looking like pressing toothpaste out of its tube: >>> whiskers? The guy (who was it?) meant that CBGAs build up mechanical >>> stress unlike other components, and hence create whiskers. >>> >>> Lead whiskers? Quadruple Hmmm. The litterature is very thin about >>> Lead whiskers, not to say nearly non-existent. A few cases are >>> reported, but not regarding any BGAs, as far as I know. However, I >>> will study the few samples I got (am not allowed to touch the sharp >>> boards)and see if it can be Lead whiskers, or other type of Lead >>> crystals. According to Sod's law, I may be the one to be haunted by > Lead whiskers... >>> >>> Inge >>> >>> >>> -----Original Message----- >>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Fenner >>> Sent: den 4 september 2006 09:38 >>> To: [log in to unmask] >>> Subject: Re: [TN] PbCO3 >>> >>> Double Hmmmm! >>> >>> Applying Occam's Razor to this. Put everything you have done to one >>> side for a moment and just imagine you were at the early stages of >>> investigating this problem. >>> You would describe a situation where you are using a reputable resin >>> based flux and then clean them in a reputable semi-aqueous cleaner. >>> Everywhere is OK, except under a large component. >>> My immediate thought would be that you are not cleaning under the >>> component as well as you think or at least are not washing/rinsing >>> out the cleaner. >>> Vigon is a very high pH material and therefore chemically active. >>> How do you know you have cleaned under the device? Are you lifting it > >>> off to do something like ROSE? If there is a flush though problem >>> then ROSE will not detect it. >>> My apologies for pointing out what is basic stuff like this to >>> someone with your knowledge/experience, but sometimes it is easy to >>> overlook something when it is too simple. >>> >>> >>> Regards >>> >>> Mike >>> >>> >>> >>> -----Original Message----- >>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Hfjord >>> Sent: Sunday, September 03, 2006 10:19 AM >>> To: [log in to unmask] >>> Subject: Re: [TN] PbCO3 >>> >>> Hmmm.... >>> >>> I have excluded residues that stem from reactions with the solder >>> mask and other reactions from solvents and fluxes. The reason is, >>> that such residues appear immediately after the soldering process, >>> while our residues GROW slowly during weeks and months. And only on > CBGAs. >>> Furthermore, we have investigated the space between the CBGAs and the > >>> board, and it's absolutely clean, because we use a very effective and > >>> powerful Vigon 200 washing machine. >>> So, it is still a mystery. >>> >>> Inge >>> >>> >>> >>> ----- Original Message ----- >>> From: "Mike Fenner" <[log in to unmask]> >>> To: <[log in to unmask]> >>> Sent: Thursday, August 31, 2006 4:20 PM >>> Subject: Re: [TN] PbCO3 >>> >>> >>> >I can puzzle out how you could get carbonate but not how you would >>> >get lead carbonate. Lead is unreactive compared to other metals >>> >present and they would react in favour of the lead, or even if the >>> >lead reacted would displace it in the corrosion cell reaction. >>> > If you are getting significant carbonate formed so quickly then >>> >this would imply a fairly high acidity on the work, which is hard >>> >to relate >>> >>> >to that found in electronic grade fluxes. >>> > >>> > You have nothing to lose by trying an activated rosin base flux to >>> > reduce this stuff -whatever it is - and floating it away as a >>> > slag/dross in the rosin, but I doubt it would be effective unless >>> > you >>> re-melted the solder. >>> > If >>> > you were to do that it would be similar to some purification >>> > processes >>> >>> > for solders [and other metals,] >>> > >>> > >>> > Regards >>> > >>> > Mike Fenner >>> > Indium Corporation >>> > >>> > T: + 44 1908 580 400 >>> > M: + 44 7810 526 317 >>> > F: + 44 1908 580 411 >>> > E: [log in to unmask] >>> > W: www.indium.com >>> > Pb-free: www.Pb-Free.com >>> > >>> > >>> > >>> > -----Original Message----- >>> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Ingemar >>> > Hernefjord >>> > (KC/EMW) >>> > Sent: Thursday, August 31, 2006 9:21 AM >>> > To: [log in to unmask] >>> > Subject: [TN] PbCO3 >>> > >>> > >>> > We got lots of such growth on CBGA balls recently. After >>> > soldering/cleaning: nada. After one week in stock: signs of growth. >>> > After one month: unacceptable crystals. Now, being insoluble in >>> > water and many solvents, some specialists advise you to mix an RA >>> > with ethanol, heat this mixture and dip the part until the crystals > vanish. >>> > My question to TN is whether there is alternative methods? Some >>> > accept >>> > PbCO3 growth as being harmless, but this is not our intention, >>> > because >>> >>> > loose particles are semiconducting and can create leakage current >>> paths. >>> > >>> > Brian's book "Cleaning and Contamination of Electronics and >>> Assemblies" >>> > mention there are five groups of white residues, but, oddly enough, > >>> > lead carbonate is not included. The chemistry world of soldering >>> > residues is so complicated, that I have to ask you for help. >>> > >>> > Thanks in advance >>> > Ingemar Hernefjord >>> > Ericsson Microwave Systems >>> > > > --------------------------------------------------- > 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 -----------------------------------------------------