Hi!
  I'm research fellow and engage in FIB technology in Singapore. I can
answer a part of your question.
  How about using chromium(Cr) to instead of Au or Al.  I think chromium(Cr)
has a good adhesion with substrate.The conductivity can be looked for from
MEMS Website about materials performances.
  Both sputtering and thin film evaporating can be used for coating. The
adhesion depends on cleaning degree of the substrate. Fron the working
principle point of view, there is no obvious distinction for adhesion
between the mehtod of sputtering and thin film evaporating.

   Fu Yongqi
Research Fellow
Precision Engineering Lab.
School of Mechanical & Production Engineering
NANYANG TECHNOLOGICAL UNIVERSITY
NANYANG AVENUE
SINGAPORE 639798
23/12/1998

> -----Original Message-----
> From: Bernstein, Jacob [SMTP:[email protected]]
> Sent: Tuesday, December 08, 1998 10:34 PM
> To:   [email protected]
> Subject:      metallization/interconnect
>
> My name is Jacob Bernstein. I work for News Digital System (Israel) at the
> failure analysis Lab.
>
> I'd  appreciate very much your advice on the following practical problem
> that I face.
>
>    For failure analysis of individual silicon chips I need to create
> interconnections over the oxynitride passivation layer and
>    underlying Al signal lines to facilitate electrical probing.
>
>    I use lift -off  technique for contact lines deposition, followed by
> FIB
> technique with Pt for via.
>    I am currently using a  vacuum thermal evaporation system for
> deposition
> of the contact lines
>    (  Au, 300 nm with Cr, 30 nm adhesion layer);
>
>    I had  reasonable results, the only problem being that the high
> temperature of evaporation  causes  heat damage to
>    the photoresist.
>    Because of the above problem , I am considering to buy an inexpensive
> SEM
> sputter coater with  for contact
>     deposition.
>
>   What I have to know, though, is:
>    1)  If I will use  sputtering, will the ADHESION be as good as with
> thermal evaporation?  do you   suggest perhaps  the use of other metals ?
>    2)  What is the expected conductivity ?  specifically , how good will
> be
> the contact to the
>       chip's Al lines ?
>
> Another practical problem which I face is: instead of touching the contact
> lines with probes, is it possible to
>   somehow wire-bond them ?  (The wide of the contact line is 50u).
>  I can't use normal UltraSound bonder because it will "kill" the chip.
>
> Thanks in advance,
>                                        Jacob Bernstein
>
>