Hi Karen,

You can take advantage of the ability of metals like Aluminum (which
will form a eutectic with Silicon at 477c), if you can go to that
temperature then an Al/Si bond would work, it can be done in either
vacuum or a N2 purged furnace. Also be aware that it will tend to dope
Silicon P-type. Other metals that would work are Au, Sn, Pb, In however
these may not be compatible with the fab.

Rick Morrison


Karen Smith wrote:

> I am looking assistance in finding techniques to join a silcion wafer
> (n-type) via an electrically conductive bond to a conducting handle
> wafer (preferably silicon). The issue is further complicated by the
> need to free the silcion device wafer later in the process, for the
> bond to be HF resitant and to not represent a contamination risk in a
> CMOS fab.
>
> Anodic bonding, fusion bonding and Si-Au eutectic bonding are thus not
> appropriate.
>
> Can anyone help me by suggesting possible avenues for me to
> investigate further, such as suitable metal eutectic/conductive
> adhesive/conductive polymer/solder layers? Details of companies
> already offering (or planning to offer) such services would also be
> gratefully received.
>
> Many thanks in advance for you assistance,
>
> Yours sincerely,
>
> Karen Smith
> Microsystems Consultant
> Coventry, UK
>
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