Russell, There have been a number of follow-ups to your initial questions in your initial post, and most of them have dealt with the "gold embrittlement" issue to some extent, but have not really explained it very well to you, so that you can see the importance of asking the customer about his soldering process, so I will expand a little bit here. When gold is present somewhere in a joint that is soldered, some of the gold goes into "solution" and alloys with the other metals present. The presence of gold in the alloy of the solder joint causes what is known as "gold embrittlement", which I can best describe as a "crystallization" or "crazing" of the solidified solder joint that mechanically weakens the joint, and can even cause physical and electrical failure of the joint. I am not a Chemist, so my explanation may be off a little, but I am sure that there are many here in the forum who can explain the exact process much better if necessary. It is this "crystallization" or "crazing" of the solder joint that causes it to look "very dull" as you described. The amount of gold that goes into solution is dependant on two basic things: First, the amount of gold present in the joint. Second, the composition of the solder, i.e.: the specific alloy of the solder. It is this second issue that is being ignored here, and is important for you to follow up on, and the reason is as follows: Standard solder, such as Sn60 or Sn63, has the ability to "wick" or "suck" metals such copper, silver, or gold, into its' own solution or alloy, up to about 2 percent of its volume. When gold is wicked into the solution, it causes "gold embrittlement". To combat this problem, special solders have been developed which have already combined a certain amount of silver in the alloy (about 2 percent) which tends to "satisfy" the alloy of the solder so that it will no longer will "wick" or "suck" additional metal (such as the gold on the pads of your PCB in this case) into "solution". So what this boils down to is this: The "gold embrittlement" that your customer is experiencing could be caused by your putting more gold (i.e.: too much gold) on the PCB, or it could be caused by your customer changing his solder from Sn62 (which contains about 2 percent silver) to something along the lines of Sn60 of Sn63, either of which will "wick" substantial amounts of gold into "solution". The point here is that you could actually have less gold on your boards, and yet still have more gold going into "solution", if the solder was changed. To compound issues even further, today, due to the industry trying to get away from the use of lead, especially in solder, there are many new types of solder which I understand do not use lead. It is entirely possible that your customer has "updated" his soldering process to a newer type of solder, which is more susceptible to "gold embrittlement"., and that this is the cause of your problems (excepting of course the "reflection" issue with the "shiney" finish). So, it is imperative that you do in fact address the issue of solder with your customer, elsewise you may end up chasing your tail and never solving the real problem. I am not by any means up to date on any of the new solders that have been developed in recent years, or the exact reasons for their development, and as stated above, I am not a Chemist. For this reason, it might be appropriate for me to ask whether or not there is anyone else in the forum out there who could point us to a good article or discussion on these issues, so that we can get some credible source information on the topics. Hopefully this has clarified some of the issues involved. JaMi ----- Original Message ----- From: "JaMi Smith" <[log in to unmask]> To: "TechNet E-Mail Forum." <[log in to unmask]>; "Russell Burdick" <[log in to unmask]> Cc: "JaMi Smith" <[log in to unmask]> Sent: Thursday, November 14, 2002 2:48 PM Subject: Re: [TN] gold solderaility > Russell, > > It sounds like there may be some "gold embrittlement" taking place in the > soldering process with the newer boards, among other things, and while there > may be some problems on your end, such a little more gold on your newer > boards, I think that before accepting all of the blame, you need to point > the finger back at the customer and ask him whether or not he has changed > his solder, or soldering processes, or anything else in his own processing. > > You need more information from your customer in order to solve the whole > problem. > > Regarding the issue of the "shiney" gold fiducials showing up as "black" due > to the reflections, the "average" customer "should" be able to adjust the > location and intensity of his light source to compensate for the > differences. > > JaMi Smith > > * * * * * * * * * * * * > > ----- Original Message ----- > From: "Russell Burdick" <[log in to unmask]> > To: <[log in to unmask]> > Sent: Thursday, November 14, 2002 2:04 PM > Subject: [TN] gold solderaility > > > > Hello everyone! > > > > I could use some help concerning soldering to gold. > > > > Problem: > > A customer of ours has given feedback to our salespeople that hard gold > > boards we made in May 2002 were much better to solder to than what we sent > > in October 2002. Biggest difference was stated as the newest boards have > > fiducials that auto pick and place equipment can't read because under the > > lights they look "black". Under normal shop lights both boards look bright > > and shiney(sp?). > > > > Also, the customer commented that on the boards with "black" unreadable > > fiducials had solderjoints that looked very dull. > > > > Known manufacturing/processing differences between months of May and > October > > (aka, confessions of a process engineer): > > Prior to August 2002, dull plated gold boards were scrubbed to improve > > appearances. After August 2002 no scrubbing needed when a carbon treat and > > proper wetters were performed/maintained in nickel and gold baths. > > > > > > Any and all comments are greatly appreciated. > > > > > > > > > > > > _________________________________________________________________ > > Help STOP SPAM with the new MSN 8 and get 2 months FREE* > > http://join.msn.com/?page=features/junkmail > > > > --------------------------------------------------- > > Technet Mail List provided as a free 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/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 1.8e 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------