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Reply To: | TechNet E-Mail Forum. |
Date: | Fri, 10 Sep 1999 14:07:29 +0100 |
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Daan,
Can you define exactly what the platings are, in terms of thickness
and purity if any, ie Ni is 4-6uM with 0.5uM Au etc!! and what the
solders etc are Is the problem effect the whole batch, or just some of
the boards?
Regarding your specific questions:-
Prebake of boards will enhance any diffusion of Cu through the Ni
and into the Au, I cant see why this would effect solderabilty, but
may effect reliability The degree of diffusion etc will be related to
time and temp of prebake and the thickness and quality of the Ni
plating.
Effect of previous soldering operations would all effect the
diffusion as above
I assume that as long as the solder paste is relatively active it
should work fine on Ni-Au as HASL
Have you done any surface analysis of the pads? sounds like they
are contaminated with something, either from the plating, storage
handling, or even within your own facility and process.
I think we need more info, and you should get some basic surface
analysis of the pads themselves.
Roger
Motorola AIEG
______________________________ Reply Separator _________________________________
Subject: [TN] soldering to immersion gold boards
Author: "TechNet E-Mail Forum." <[log in to unmask]> at #email
Date: 10/09/99 14:17
Hi Technet,
I'm having some problems lately with soldering of pcb's with an electroless
nickel/ immersion gold conductor finishing, which brings me (after some
discussions with our board supplier) to the following questions :
Is solderability influenced by pre-baking the boards ? Does the first soldering
step have an effect on solderability for the second soldering step (double sided
reflow) ? How about the time between all these thermal excursions ?
Is it possible that a solder paste that performs excellent with HASL-boards (and
normally also with immersion gold boards) is a bad choice for soldering to
immersion gold ?
Greetings,
Daan Terstegge
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