Additionally, consider "Electroless Nickel Immersion Gold And Black Pad", R
Sakelson and S Gold, Circuitree [http://www.circuitree.com], 1/01, V14, N1,
P10
Dave Fish
----- Original Message -----
From: Ingemar Hernefjord (EMW) <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, January 22, 2001 7:42 AM
Subject: Re: [TN] Increased Phosphorus in Electroless Ni
> It's late to say thank you, Georg Milad,
> but better late than never as they say on Greenland.
>
> Someone from Shipley have been here together with the PWB maker concerning
a
> superlarge BGA soldering problem. We have learnt a lot since september but
> there remains issues still. What you said below is typical for most
articles
> and specs: layer thickness and phosphorous but little about foreign stuff
> that can appear (even for the best in the game it seems), such as fenoxy,
> epoxies, glycols, hydrates, carboxyls and a lot more. We made a TOFSIMS on
> some board lands and found SiCH3, C2H3, C3H7, Fe, C5H9, In, SnOH, just to
> mention an example. And added to that comes the morphologic aspects and
> about microhardness and boundaries and size and shape of Nickel domes.
>
> I thought I had learnt a lot about the BGA soldering, but suddenly I feel
> how empirical a lot seems to be. "We use to..." or "We think that..".
> Understand that too, but would like something more in the spec than just
> thickness and P%.
>
> If there is something I can hang up on the wall, and tell people 'this is
> how a solder pad is being done' I would be vary glad. Guess all other
> Ericsson groups agree (in silence, of course)
> Best regards
>
> Ingemar Hernefjord
> Ericsson Microwave Systems
>
> PS. Isn't Steph Meschter within Lockheed Martin any more or did he sign
off?
>
>
>
>
>
>
> -----Original Message-----
> From: [log in to unmask] [mailto:[log in to unmask]]
> Sent: den 6 september 2000 21:04
> To: [log in to unmask]; [log in to unmask]
> Cc: [log in to unmask]
> Subject: Re: [TN] Increased Phosphorus in Electroless Ni
>
>
> Here is my two cents worth on the topic of Electroless Ni , Phosphorous
> content.
> Here at Shipley our recommendation for thickness of Electroless Ni is 100
to
>
> 250 uins or 2.5 to 6.0 microns. For the gold thickness we recommend 2 - 4
> uins (0.05 - 0.10 microns) as the best thickness to protect the Ni during
> storage and not to create any Ni defects during processing.
> As far as Phosphorous content in the Ni deposit we are presently staying
> with
> 7 -9% P. We have seen data, where High phos (10 - 12%) and Low phos
(5 -7%)
>
> gave equally good results, with regards to incidences of "Black Pad".
> Our tests indicate that High Phos is prone to skip plating and gold
adhesion
>
> failure.
> The IPC Plating Subcommittee 4-14 will be meeting in Miami, during IPC
Works
>
> 2000, at 1:30 to 3:00pm on September the 11th, 2000. The agenda of the
> meeting is to define an IPC-Standard for Electroless Nickel and Immersion
> Gold as well as Electroless Gold, as surface finishes widely used in the
> industry today. Anyone interested in participating is welcome to join the
> meeting or send his input to me, and I will keep him or her informed of
the
> committee progress.
> George Milad
> Tech Marketing Mgr.
> Shipley Ronal Inc
> Chairman IPC Subcommittee 4 -14
>
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