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July 2000

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Subject:
From:
"Wenger, George M (George)" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 18 Jul 2000 13:35:12 -0400
Content-Type:
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text/plain (64 lines)
Probably not.  If you assembly process is giving good soldering reults on
all the other components and not the TSOPs it would make sense that the
TSOPs aren't very solderable.  Do you know if the surface finish on the
TSOPs is Sn90Pb10 plating over Alloy 42 base metal (with or without a Ni
barrier) of if they are PdNi plated?

The condition you discribe as "just sitting on top of the reflowed solder"
we call "foot-in-the-mud" which we believe is a combination
soldering/solderability issue.  What stencil thickness are you using for the
TSOPs?

> ----------
> From:         Thomas Han[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Thomas Han
> Sent:         Tuesday, July 18, 2000 9:17 AM
> To:   [log in to unmask]
> Subject:      [TN] Reflow Issue
>
> Hi all,
>
> I have been noticing on our last batch of boards that we ran, some of the
> tsop flash chips were not reflowing properly.  I am not getting very good
> toe fillets on the chips and some appear as though they are just sitting
> on
> top of the reflowed solder.  This board has a good component mix(i.e. BGA,
> QFPs, PLCCsocket, SOICs, total(325-350)).  Other components reflow fine,
> but for some reason these TSOPS are not.  Is there something that we are
> overlooking?
>
> Your input would be greatly appreciated.  Thanks in advance
>
> Tom
>
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