I need to do an anisotropic silicon dioxide etch, that uses aluminum
as the etching mask. The oxide thickness is about 5um. The high-aspect
ratio should be 2.5:1 or better, and the aluminum to oxide etching
ratio should be 1:10 or better.

I am looking for an SF6 based oxide etching recipe that will meet the
above specifications. The system I have is a Unaxis ICP etcher, with
the following gases available: Ar, SF6, O2,CH4, H2, N2

Any suggestions/help will be appreciated. Thanks in advance.

Ankur