Hi everyone,

we would like to set up a TMAH-process for making MEMS on a silicion on
insulator (BOX) substrate. As we have hardly any experience with such a
process in our cleanroom I would like to ask some very basic questions:


1. Are there any pecularities with SoI substrates?

2. Does the underetching rate suffer from very thin layers (70nm Si
under 70nm thermical oxide)?

3. How thin can suspended SiO2 bars (1-2=B5m width) become until they bre=
ak?

4. Does the quality of TMAH solutions depend much on the supplier? Does
anyone have experience with the 25% aqueous solution by ABCR (German
company)?


Hopefully somebody can help!
Thx, Jan.