I agree with Mark and Dave Fish. The CircuiTree article is excellent and
makes the best case yet that I have seen regarding the cause and elimination
of "Black Pad".
Thanks,
Robert Furrow
New Product Engineering
Lucent Technologies
978-960-3224 [log in to unmask]
> -----Original Message-----
> From: Mark Mazzoli [SMTP:[log in to unmask]]
> Sent: Monday, January 22, 2001 11:58 AM
> To: [log in to unmask]
> Subject: Re: [TN] Increased Phosphorus in Electroless Ni
>
> In case you guys haven't had a chance to see it yet, there's a great
> article in January's issue of CircuiTree regarding ENIG and black pad. It
> states, among other things, that those of you who are dealing with a
> modified general metal finishing bath (as most are) will most likely
> suffer
> some amount of black pad (in essence, regardless of phosphorous
> content). The cause of the black pad phenomenon has been found and fixed,
> and it has nothing to do with phosphorous.
>
> Mark Mazzoli
>
>
>
>
>
>
>
> At 04:42 PM 1/22/01 +0100, you wrote:
> >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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