In a message dated 6/1/98 8:19:52 AM Pacific Daylight Time,
[log in to unmask] writes:

<< We are experiencing termination loss of chip capacitors and chip
 resistors after the reflow process.
 Can anyone told me the possible causes?
 Is it a material related problem?Since we have already checked the
 reflow profile and found to be within specification.>>

Hi Bobby!

      I've run across this a couple of times...is the capacitor some strange
1/25% tolerance value? The ones that I had were, and I remember a part called
a "Thermistor" (I think it's a resistor that changes value with temperature)
that I had the same problem with...

      You had it right, it is material related...at least the ones that I had
were. There's been no nickel barrier plating on the terminations...they're
probably silver, or palladium silver...it's all getting leached off in the
solder joint.

      You also want to do everything you can to keep from having to do any
touch-up on these parts (as you've probably discovered already), you put a hot
soldering iron to it, and POOF! The termination completely vanishes!

      These parts can't take any heat for any length of time at all, so you
need to adjust all your temperatures down just as low as you can (without
becoming cold of course), and then go to the buyer and ask if they can get the
same value part with a nickel barrier plating...

C-ya!

-Steve Gregory-

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