> I plan to use some kind of polymer (prefer Teflon) to
> cover my device surface as a passivation layer. The
> trench I need to fill is about 6-10 um. I want to have
> a flat surface after spin-on this passivation layer
> and still cover the trench very well. Does anyone has
> the similiar experience before. And could you please
> recommend me some kind of polymer with can be used
> here (prefer temperature no higher than 250C) ? And I
> also perfer not to have the CMP process after the
> spin-on coating. Please let me know the vendor name
> too.

Try Futurrex at http://www.futurrex.com/
They make some positive and negative photoresist
and spin-on planarization layers.
I have seen some amazing SEMs of a spin-on layer over DRIE trenches.
I have not used the products myself, however.

        --Kirt Williams Agilent Technologies