Hi Stephan,

We have used AZ-P4620 with good results.  A hard bake after developing will
help the selectivity but will also cause the photoresist to shrink a little.
We have also used multiple layers of AZ-P4620 to achieve 500 micron depths,
but the lithography for a two layer resist can be tricky.  Final etch depth
with this resist will depend on the amount of exposed silicon on your design.
If possible minimise the amount of exposed Si.

--
Shane McColman
Research Professional
NanoFab, University of Alberta

On May 20, 2005 04:44 am, Stephan Biber wrote:
> We want to use the "Bosch-process" for DRIE of silicon structures. Does
> anyone know which photoresist is good to provide very high selectivity
> to the DRIE process? We want to etch more than 300µm deep with only
> one photomask! What is the right resist for this application?