Use squeege (screen prinitng) to fill the trench and
use P.L as a tool to imprint only on the trenches.

Bala.

--- Ying Cai  wrote:

> Hi, dear all,
>
> Now I have a large trench (1mm wide, 1mm long, 4 um
> deep)  in the si
> substrate. I'd like to fill some material and make
> the surface flat.  The
> whole sample is 1" by 1".
>
> Could you give me some suggestions how to do it?