I thought Mark was referring to Mike Walsh's article in Circuitree (January 2001). In either case, Mike Walsh is not "discounting the previous work or theories," but "offer here a new and novel description of the black pad problem and its possible elimination." And, they strongly believe that their "work shows that the problem of black pad and many of the other plagues of ENIG are traceable to the nickel bath."
Ingemar, I think any of those instruments would be fine, although I don't expect that layer to be organic, so you may want to exclude FTIR. XPS will probably help, because it also gives you the binding energies of the elements detected.
Hans Shin
Pacific Testing Laboratories, Inc.
http://www.pacifictesting.com/
-----Original Message-----
From: Ingemar Hernefjord (EMW) [SMTP:[log in to unmask]]
Sent: Tuesday, January 23, 2001 3:51 AM
To: [log in to unmask]
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,
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