It's a while since I used or saw any of this sort of part. But my memory
tells me that sometimes apparent stains "developed" over a period of long
storage. Most of the time we were never able to identify them. We actually
thought this more likely a surface effect rather than a chemical
contamination.
We actually weren't too bothered as at this thickness of gold it always
double dipped off in solder pots before soldering to substrate. Focus was
therefore on "did the leads evenly coat with solder etc..." If they did (and
they always did) we reasoned it didn't matter as even if it were physical
contamination it would be washed off and therefore irrelevant.
And pragmatically we reasoned if it went further in it still didn't matter
if the solder was unaffected as that could be regarded as a repair or
rectification.
Hope this helps
Regards
Mike Fenner
Indium Corporation of Europe
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 joyce
Sent: Friday, July 25, 2003 1:05 PM
To: [log in to unmask]
Subject: Re: [TN] Gold plating shelf life and discoloration resolution
1.5 micron gold will have solderability problem anyhow... No exposed
copper (or no exposed base metal) should be part of purchesing
requirement... If nothing being specified...you asking for trouble. (if
it is mil-part, you are OK to return to the vendor... It is in the
Mil-std-xxx reference to another Mil-std-yyy and reference to .... Goes
on and on and on... Even it is not spelled out in the requirement, you
somewhat covered on the issue... Unless someone specifically made
"exception" ;-).
jk
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of
>Barmuta, Mike
>Sent: Thursday, July 24, 2003 6:35 PM
>To: [log in to unmask]
>Subject: Re: [TN] Gold plating shelf life and discoloration resolution
>
>
>Hi Joe: First a couple of questions to help answer your
>question: 1. Has the gold thickness been verified to be > 1.5
>microns on the actual parts? 2. What type of gold plating is
>it? 3. What is the type and thickness of the Ni plating? 4.
>What is the problem the discoloration is causing, is it
>solderability or is it a perception that they will be a problem?
>
>As for comments in general:
>1. If they were "properly" plated with electroplated 3-5
>microns of Ni followed by 1.5 microns of electroplated hard
>gold, the one year shelf life should not be a problem. Thinner
>or different types of plating could be problematic. With a
>proper Ni undercoat as specified I don't think the porosity
>should be an issue. I also don't understand the vendors
>comments on baking, doesn't make sense. If it's a
>solderability problem baking could make them worse and sure
>won't help the discoloration.
>
>2. As for the vendor, I feel they should have been willing to
>have some of the parts returned for analysis to determine if
>the were defective or not and if they met the drawing/spec.
>However you don't say whether it is a real problem or
>perceived, just that the parts are discolored. I think the
>vendor needs to know exactly what the issue is that he's being
>put on the spot for.
>
>
>
>Regards
>
>Mike Barmuta
>
>Fluke Corp.
>
>Everett WA
>
>425-446-6076
>
>
>
>-----Original Message-----
>From: Joe Fjelstad [mailto:[log in to unmask]]
>Sent: Thursday, July 24, 2003 2:56 PM
>To: [log in to unmask]
>Subject: [TN] Gold plating shelf life and discoloration resolution
>
>
>Hello friends from around the globe,
>
>Component time limits seem to be a sore spot these days. This
>brings to mind a related topic.
>
>You see, I have a friend with a problem...
>
>(I know what you might be thinking but the answer is: No, it
>really is not
>me ;-)
>
>At any rate, he received a quantity of ceramic chip carrier
>package shells with gold plated leads over a year ago and upon
>removing them from storage found many of them to be discolored
>near the copper/gold brazed welds (apparently due to moisture
>from micro pores in the welds) The welds with the micro pores
>were over plated with nickel and gold, with the final gold
>plated to an average of greater than 1.5µm (60 millionths of an inch).
>
>The vendor told him to bake them but it is hard to see how
>this will remove and discoloration. They are also refusing to
>replace or repair the parts nor will they say if the packages
>will be reliable in the field or take any responsibility for them.
>
>I realize that times are hard but the response seemed rather
>uncaring and not very service oriented.
>
>So the questions are:
>
>1) What is the consensus expectation for storage life of gold
>plated parts on a shelf in a benign environment with the
>plating series above?
>
>2) What is the concessus on how folks here feel that the
>vendor should respond?
>
>A) Replace the parts? B) Repair them? or C) Tell the customer
>to eat them?
>
>There are no right or wrong answers here. I am just looking
>for the valued opinions of the many here who spend every day
>in the trenches on this
>particular matter.
>
>Thanks in advance to all who respond.
>
>Kindest regards to all,
>Joe ---------------------------------------------------
>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
-----------------------------------------------------
---------------------------------------------------
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
-----------------------------------------------------
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
This email, its content and any files transmitted with it are intended solely for the addressee(s) and may be legally privileged and/or confidential. If you are not the intended recipient please delete and contact the sender by return and delete the material from any computer. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited.
Messages sent via this medium may be subject to delays, non-delivery and unauthorized alteration. This email has been prepared using information believed by the author to be reliable and accurate, but Indium Corporation makes no warranty as to accuracy or completeness. In particular, Indium Corporation does not accept responsibility for changes made to this email after it was sent. Any opinions or recommendations expressed herein are solely those of the author. They may be subject to change without notice.
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
---------------------------------------------------
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
-----------------------------------------------------
|
