Cedric,
I've been involved in RF component soldering for decades, and I know your
frustration. Very, very typical. Have you swept anything across the room
to hit the wall yet? Or rushed out from lab and gone fishing instead? No?
You will.
Your choice of parts to join together are not so remarkable, thou not very
common. Before discussing any radical changes, I would like to give you
advice number one, if you don't already apply :
Before soldering, place the assemblies in a oven at +50..80C for one hour in
order to get rid of as much volatiles as possible (varies a little from
paste to paste).
2bc'd
Inge
>>
>> Dear Technetters,
>>
>> We have to solder a RF power transistor onto an aluminium base plate and
>> we
>> are facing with a very challenging issue.
>>
>> We encountered a high voids rate (>30% or 40%) underneath the component
>> body
>> (which is about 35x10mm). This is not acceptable for this application.
>>
>> The component is Nickel/gold plated whereas the aluminium baseplate is
>> plated with Nickel and Silver and then cleaned with solvent.
>>
>> We tried to change/adapt:
>> - soak time of the profile,
>> - 2 difference solder pastes (SAC305),
>> - change the screen design and thickness
>>
>> Finally none of these parameters looks to have significant effect on
>> voids
>> rate. We are now wondering if the solderability of the Ni/Ag plating is
>> good
>> enough and even if it is convenient for that purpose.
>>
>> Is somebody could give us advises? How to enhanced NiAg plating
>> solderability (acid ?!, ...)? Which flux could help to compensate the
>> poor
>> wettability? Which kind of plating would be preferable? ...
>>
>> Thanks and regards,
>>
>> Cedric
>>
>>
>>
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