From literature and others' suggestions I was led to believe that to get
vertical walls I would have to use 110 Si wafers.  The channel I am
etching is only about 200um wide and 500um deep.

Connie Smith
Rice University


On Mon, 7 Jan 2002, Knighton, Ed wrote:

> Hi Connie, If you switch to <100> Si Wafers Your problem will go away.
>
> Ed Knighton, Process Engineer
> Constellation Technology Corp.
>
> > -----Original Message-----
> > From:       Connie Kathleen Smith [SMTP:cksmith@ruf.rice.edu]
> > Sent:       Friday, January 04, 2002 1:40 PM
> > To: mems-talk@memsnet.org
> > Subject:    [mems-talk] 110 Si etching with 20%KOH
> >
> > I am trying to fabricate a flow channel with vertical side walls using a
> > <110> Si wafer.  When I etch all the way through the wafer (which is
> > desired) the side walls are slanted.  The wafers are coated with SiO2 and
> > Si3N4 as protective barriers during etching.  I expected to lose several
> > microns vertically during etching but the slanted walls were unexpected.
> >
> > Thank you,
> > Connie Smith
> > Rice University
> > Department of Chemical Engineering
> > 6100 Main MS 362
> > Houston, TX  77005
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