Try John DiLazzaro at <[log in to unmask]> or phone (503) 526-5263. He must know a lot in that region. Advanced MCM maker. Thanks for wire bond response. Superthin "lubricants" are nasty things, yes. I made following experiment on a hopeless non-bondable gold : sputtered approx. 50nm Au on it, and found that it had changed to 100% bondability! Now, exactly what happened, I don't know. The molecular bombardment may just have removed such a thin film that you talk about, or covered it with Au. Agree, Carey, I have been starting up such investigations a couple of times, and each time I find that it ends in such scientific a panorama that time runs out and costs become unproportional. Best way is to talk with the supplier, or even change supplier if you have the choice. I have FlipChip questions in this matter too, but I will save it so you can get your breath back.
Take care(y)/Ingemar


3) Wire bonding: A rough surface (e.g., spiked) will just "moosh" (for lack
of a better term) all around.  Surface cleanliness depends on how you clean
your surface and the residue it leaves behind.  Water and oxides will always
be present (except Au oxide is unstable at room temperature).  Thin films
and interfaces can be extremely strong.  The strength of thin films can be
1000X higher than bulk equivalents and their other properties (e.g.,
electrical) vary as well with thickness.  Auger (pronounced o-jay (a french
"je") for you non-surface scientists) is useful because it can easily
explore the composition of the top 500-3000 angstroms (it's accuracy is
about 50 A).  But you pay $150/hr (one way or another in a big company).
But that's only for gross contamination during film deposition (plating or
sputtering).  Also, AES (another way to say Auger) is not useful on rough
surfaces because you can't tell it's depth from the surface.  About solving
this for you, I don't think I can from here.  Yes, I'm a thin film
metallurgist (presently looking for some work in Portland in this field if
any of you have connections), but the problem you have is very
equipment/metal-system dependent.  It's like long distance surgury.  I am
available as a consultant (but I get expensive), but first I recommend
calling your suppliers and trying to network through them to find an
industrial partner (nearby) that you can visit and get ideas.  Serious
problems are not solved in a day or even a week (which many of my clients
loath to hear).

Carey

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