Try using 80% weight KOH Solution at 85 C .It gives a smoother surface than
30% weight solution,but etch rate is lower than 30% weight solution.



On Tue, 27 Apr 2004 Armin Werber wrote :
>Dear all,
>
>I want to use the KOH etched {111}-planes as mirrors. In a first
>experiment I used a KOH solution with following properties:
>concentration: 30% KOH by weight
>temperature: 85°C
>magnetic stirring
>
>The result: the roughness of the mirror planes is with about 150 nm rms
>extremely high (messured with zygo white light interferometer).
>I have read about the use of IPA to change the wetting properties of the
>solution. (less gas bubbles adhesion on the etched surfaces)
>So knows anybody the right formula for KOH-etching to achieve smooth
>{111}-planes?
>
>Kind regards,
>                         Armin Werber
>
>
>
>
>
>
>Institute of Microsystem Technology
>University of Freiburg
>Georges-Köhler-Allee 102
>79110 Freiburg
>
>Tel.: +49 761 203 7518
>Fax.: +49 761 203 7562
>
>   werber@imtek.uni-freiburg.de
>  
>www.imtek.uni-freiburg.de/micro-optics
>
>_______________________________________________
>MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list
>options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
>Hosted by the MEMS Exchange, providers of MEMS processing services.
>Visit us at http://www.memsnet.org/