Ingemar:  You're correct.  Much the current literature is from the
perspective of the front-end boiling caldrons.  An exception is .

 "A Failure Analysis And Rework Method ." Z. Mei, et al, SMTA International
1999, p407

. which I can't put my swarmy little hands on [must have been far too
efficient during one of those mad clean-up the office sessions].

Dave Fish

----- Original Message -----
From: Ingemar Hernefjord (EMW) <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, January 23, 2001 3:51 AM
Subject: Re: [TN] Increased Phosphorus in Electroless Ni


> Guys, I begin to feel schizo,
> one says this and another that, and me being slow thinker, not easy. Mark
you said this: "The cause of the black pad phenomenon has been found and
fixed,
>  and it has nothing to do with phosphorous!" And you refer to CircuiTree's
article by George M. But he pointed that phosphorous was one of mayor
concerns, didn't he?: " Major factor Effects on black pad formation are The
Structure of Nickel deposit, The Phosphorous Content of the Nickel deposit,
The Uniformity of the Nickel and Gold Coatings and finally The Corrosion
Rate of the Immersion Gold."
>
> Another one, not Mark, but all of you: Lucent's people have led us back to
the central issue, the dark, thin, brittle and elusive shadow, I mean the
extremly thin layer between ordinary Ni3Sn4 and the Nickel on the lands. I
have asked a lot of people about their experience of compund findings, but
no respons yet. What tool do you recommend for examination the layer? EDS?
FTIR? XPS? SIMS? or what? Cross sectioning with polishing seems to smear and
mislead. Suppose that the BGA falls of, caused by this layer, then you must
have the content of the thin layer on one or two parts, either on the BGA
balls or on the board lands. If you have these parts in your hand, what
would you do then to find out what the brittle P-rich layer is? In my
reporting I need add who was the murderer.
>
> Sorry for harping this matter over and over again.
>
> Ingemar
>

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