Dwight and Bev,
I noticed your enjoyment about bad wetting on ENIG. I am trying to find
cause for solder ball lifting and have now come to the conclusion that the
ball wetting on the board lands look strange after pull test. Don't seem
quite good. The question is if I have to do with bad wetting or dewetting.
Can I send some pictures to you for discussing? Guru Anglemair got some,
but maybe he has little time to spend on me. The BGA maker is now
crossectioning parts in Sivalley, but even they may miss something, TN has
witnessed many a times how intricate these matters are, noone is the
complete Master of BGA Soldering.
Ingemar
From: Dwight Mattix [mailto:[log in to unmask]]
Sent: den 29 november 2000 00:03
To: [log in to unmask]
Subject: Re: [TN] Ni/Au solderabilty
It sounds like perhaps this is similar to some ENIG wetting problems we've
"enjoyed" in the past. A few questions about your soldermask...
* What type S/M is used?
* Is this board SMOBC or S/M after ENIG?
* Are there S/M plugged vias?
* If so, at what point in the process are the vias plugged?
* Do you see any relationship between the non-wetting pad locations
and vias?
* Are the problem pads etch defined or S/M defined?
regards,
Dwight
At 02:09 PM 11/28/2000 +0000, Burtt, Nigel wrote:
Unfortunately Bev, it is definitely not "black pad." Totally random pads
completely or partially fail to wet leaving blob of solder on apparently
clean gold surface - we see this on small BGA lands and 1206 lands
Thanks
> -----Original Message-----
> From: Bev Christian [SMTP:[log in to unmask]]
> Sent: Tuesday, November 28, 2000 1:14 PM
> To: 'TechNet E-Mail Forum.'; 'Burtt, Nigel'
> Subject: RE: [TN] Ni/Au solderabilty
>
> Nigel,
> When you say random, how random? Does it appear to mainly happen to small
> pads connected to large pads elsewhere on the boards? If so, read up on
> black pad syndrome in the TechNet archives.
>
> regards,
> Bev Christian
>
>
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