I have one,

you ICP etched your cavity of 1x1. Then deposit your metal layer. Then, you
spin resist and pattern a rectangle or 2 x0.98. With this process you will
fully cover 2 sidewalls, and the 2 other will only be covered about 10 um on
each side... should be all right ! Finally etch your metal and remove the
resist.
Hope it works
florian


Quoting "Xiaoguang \"Leo\" Liu" :

> Dear all
> I've been working on a project in fabricating cavity electromagnetic
> resonators that require partial metallization of the side walls. For
> example, I would like to produce a rectangular cavity  in the silicon
> substrate by DRIE. I would then want 2 of the 4 side walls to be
> metallized with gold while keeping the other 2 silicon. I've thought
> really hard about this but could not find a way to meet the
> requirement. The cavity in consideration is about 1mmx1mm big.