"he received a quantity of ceramic chip carrier
package shells with gold plated leads over a year ago ..."
Is it common to buy parts, apparently accept and pay
for them, then store them for a YEAR and then be able to go back to the supplier
and demand restitution because the parts don't suit you??
Unless of course there is a contract between the parties that specifies the
supplier forever guaranteed the parts (or solderability of the parts),
regardless of time, usage, storage conditions, etc. I hope the supplier
wasn't that stupid.
Regardless of what is wrong with the parts, I believe
the supplier is perfectly justified in refusing to take the parts back.
(Can Joe's friend provide proof as to actual storage conditions??)
Patty
Patricia J. Goldman PPG Industries, Inc. 724-274-3417 fax:
724-274-3333 [log in to unmask]
www.ppgelectronicproducts.com
Joe,
If it
is a high temp leaded cofired ceramic package that I am used to, the high temp
ceramic parts are typically brazed with a copper/silver eutectic alloy
(~780°C). Any leads will typically have been pre-plated with at least a
flash of nickel. Following the brazing operation (in a reducing
atmosphere), the entire joint is nickel and (most often) SOFT gold plated,
otherwise nothing could be wire bonded.
If the
gold is porous AND the parts are subjected to heat and room environment,
solderability/wire bondability will be affected (over a time period of weeks and
months), but you have virtually virgin parts!! "Storage" is humidity
controlled, right?
My two
bits is that you have poor (or should I say, 'pore' plating). The base
metal stain should not be coming through 60 microinches of decent gold and
underlying nickel plating unless there is a pore, or a crack, or a scratch of
some kind. As a point of verification, can you pop the part in a SEM and
run an EDS on it to see if you see Fe if a kovar, or alloy 42 lead frame (or
Copper if copper based)? These elements should not be at the surface of
the gold of a virgin part.
If he
were to place the component in a salt fog environment alongside a 'good' package
style, the one with porous plating will fail much sooner...
Baking
sounds like a plating adhesion test. If porous platings, the problems will
only get WORSE.
I
would think that a decent supplier would acknowledge that staining/discoloration
is NOT a normal condition, and would take the parts back for FREE
replacement (unless they are a special design, and something about the
design promoted to the problem).
Otherwise, it sounds like someone had some crap on the
shelf they wanted to unload.
I would not be in
favor of use of these parts without seeing pictures of
the severity of the problem
Steve
Creswick - Gentex Corp
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 ---------------------------------------------------
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