Hi.

Do you want to make it porou/hydrophobic or just rough? There are
techniques for making porous silicon, look for instance at: DOI:
10.1021/ac034425q

When it comes to glass ,it depends on what kind of glass you're
using, but I think I've seen somewhere that phosphoric acid can be
used to increase the surface roughness and create a "matted" effect
as seen on light-bulbs.

Not much help but maybe you find something there :S

cheers

Mikael

On 9 maj 2008, at 23.13, Zhao Lu wrote:

> Hello,
>
>      In my project, I need to increase the surface roughness of
> silicon, glass
> substrate or SU8. The surface roughness should be around 1 to 2um. Any
> suggestion will be hightly appreciated.