A post-etch processing step that might help you is annealing in hydrogen at
10 Torr, 1100 C, for a few minutes.
This smooths rough silicon surfaces and rounds corners.
This was reported by M.-C. Lee and M. C. Wu from UCLA last week at the
Hilton Head conference.

----- Original Message -----
From: "Vipul Patel" 
To: 
Sent: Wednesday, June 16, 2004 11:22 AM
Subject: [mems-talk] KOH Etching - surface roughness of v-groove surfaces


> Dear MEMS experts,
>
> I  have a need to have a mirror-like surface of the etched V-grooves (
macroscopic) using an-isotropic wet silicon etch.
> When I used conventional KOH etching ( I think it was 40% sol. at 80 deg.
C and a stirrer was used), the resultant surface has several features larger
than 2 micron.( I measured it by cleaving the V-groove and measuring the
surface roughness of the etched surface by dektek profilometer.)
> The crystal plane was aligned to better than 0.05 deg. during lithography
process using an additional mask.
> I came across several papers related to improving the surface roughness,
however being an Electrical Engineer, I do not understand chemical etching
well. Our goal is to have a surface with less than 0.1 micron peak-to-peak
roughness on macroscopic level ( across a few mm long facet)
>
>  Can anyone suggest on what changes should I make to etch process and
share their experience?  Do I have a spec. that is not doable? Eventhough I
have no experience, I can probably also try TMAH or EDP solutions. Also,
does anyone recommend a  MEMS foundry with experience in this specific area.
If they can guarantee the spec. , I can probably give them the entire
device/wafer fabrication.
>
> With best regards,
>
> Vipul Patel..
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