Hi Jorge! An 85Sn/15Pb solder alloy has a melting (pasty) range of 183C -
209C. Have you checked the solderability of the QFP leads? An 85Sn/15Pb
solder alloy is going to be more prone to having oxidation problems because
of the higher Sn content. Are other components on the same assembly having
similar problems or do you get acceptable solder joints? If the other
components are ok I would investigate the QFP solderability using the
JSTD-002A specification. Good Luck.

Dave Hillman
Rockwell Collins
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Jorge Rodriguez <[log in to unmask]>@ipc.org> on 11/27/2001
04:17:09 PM

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Subject:  [TN] Need Help with 85-15 Altera QFPs


> Fellow Technetters:
>
>       I am sending this looking for any help, I guess I've done
everything
> as far as the process and I haven't been able to resolve the issue. We've
> been having soldering problems for a while with QFPs with 85 Sn/15 Pb
> finish on the leads. The solder doesn't flow properly and an acceptable
> solder joint is not formed, the leads can be sometimes lifted with no
> effort. The solder paste was checked after the screen printer operation
> and it looked alright, the oven profile was also verified and it's always
> within the solder paste manufacturer's recommendations. This problem
seems
> to be affecting all the different products with this type of component.
> These part numbers are manufactured by Altera. Has anybody experienced
> similar problems with QFPs from this manufacturer?, Does anybody have
> recommendations as far as the reflow oven profile?. I read somewhere that
> this particular alloy has the liquidus temperature at 205 degrees, is
this
> accurate?
>
                Any help would be really appreciated

> Jorge Rodriguez
> Process Engineer
> Varian Electronics Manufacturing
> E-mail: [log in to unmask]
>

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