Hi James,
it's a long time since I saw your message. At that time I also answered
but I have forgotten what. Was there a happy end? Have not seen you in
the Net since then.

We use to read your (Sandia's) reports of all kinds, most of them very
professional and interesting, that's why I want to give you something
back.

We are now bonding on FR4 bond pads with gold over nickel over copper.
Wire thickness is 100um and we use a Delvotec machine. The tricky thing
is to get a ductile nickel and a thin gold over that. So, our adviser
says that electrolytic nickel is the best. Nickel with Phosphorous is
very brittle and gives yield problems.

If you are still 'alive' and still working with the kind of bonding you
mentioned before, I would be glad to hear one or two words from you.

                             See you // Ingemar Hernefjord
                             Ericsson Microwave Systems




> Jim
>
> It is possible to pre heat the bond surface to 120 degrees C and
increase
> the ultrasonic energy to achieve a good bond >20g on pull test.
>
> ===== Original Message from [log in to unmask] (TechNet E-Mail Forum.) at
> 11/02/99 15:30
> >We have a need to connect a rigid flex pc board to a very small
optical
> >module.  We are in the prototype process now, on our way to an
> >instrument that will fly in space.
> >
> >We would like to wire bond using gold wire.  We are now to understand
> >the bonded surface needs to be pre-heated to 145 degrees C!!. That
may
> >not be suitable for an assembled PC board.  Aluminum wedge wire on
gold
> >pads seems be prone to "purple plague".  This will be a very short
run
> >(2 protos, 20 flight units) so we are far more interested in quality
> >than efficiency. This is not like connecting substrates to output
pins.
> >The module is 2.5" by 2.5".  We will be bonding through slots 1.5"
long
> >by .220" wide to a surface .062" below.  The bond pad size is .006"
by
> >.015".  When the two modules are together they are about a 2.5"cube.
> >Is there anyone that can provide some information gained from
experience
> >or else where that may help make this a success?
> >Thank you for your input.
> >
> >Jim Payne, Sandia National Labs [log in to unmask]
> >
> >
> >James R. Payne    MTS
> >MS 0967      Dept. 5706
> >Sandia National Labs
> >PO Box 5800
> >Albuquerque,  NM   87185
> >
> >Phone:  (505) 844-3336
> >FAX:     (505) 844-5993
> >email:   [log in to unmask]
> >
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