Hello, we tried Cr-mask for etching 2 up to 4µm SiOx or SiNx using an ICP. The
selectivity varied ca. 15-20:1, depends on the RF- and ICP-power.
Did you try etching ~10µm using ICP ?

Onny--

> Date: Tue, 3 Feb 2009 08:05:47 +0000
> From: j.grant@elec.gla.ac.uk
> To: mems-talk@memsnet.org
> Subject: [mems-talk] Deep (~10um) Silicon Dioxide Etching
>
> Hello all,
>
> I'm trying to etch square holes of dimensions ranging from 10um by 10 um
> to 64um by 64um in Silicon dioxide. The problem is I wish to etch 10um
> deep and my photoresist, AZ4562 has a poor selectivity for the various
> fluorine base gases I have tried thus far (CHF4, CHF/O2/Ar, SF6).
>
> I've been doing some reading and metal masks seem to be the solution.
> Has anyone ever done any deep silicon dioxide etching? If so any
> hints/tips/advice would be much appreciated.