MaybeYou can try align your mask with other direction, say 30 degrees
to the wafer flat(110).  As long as your groove is very long, that
would give you smaller angles.  However, at the corners, you will also
get (111) sidewalls, which is about 54 degree.

On 3/20/06, Long Chen  wrote:
> Hi, I want to have some Ebeam defined patterns of small angle slopes
> (<30 degrees), contrary to the general vertical side walls , in either
> silicon or quartz wafers. I noticed that in anisotropic wet etching of
> silicon, by aligning the crystal planes about 50 degrees pyramids could
> be formed. I'm wondering whether it is possible to achieve even smaller
> angles.