Hi Connie, Your right <110> is suppose to give vertical side walls. I
checked my referance (Fundamentals of Microfabrication by Marc Madou). Sorry
for the mis info.

Ed Knighton

> -----Original Message-----
> From: Connie Kathleen Smith [SMTP:cksmith@ruf.rice.edu]
> Sent: Monday, January 07, 2002 10:41 AM
> To:   'mems-talk@memsnet.org'
> Subject:      RE: [mems-talk] 110 Si etching with 20%KOH
>
> 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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