stsetch systematic problems

Benjamin Chui bwchui at yahoo.com
Mon Nov 28 17:02:33 PST 2005


It may be due to chamber particulate problems (at least the
micrograssing part).

Ben


--- Huang Kevin <kevhuang at stanford.edu> wrote:

> Hi,
>       I've been doing etching on SOI for 2 um wide pillars 10~30 um
> deep.
> And I also noticed footing problem and more importantly,
> micrograssing is
> getting more and more frequent for these past few months.
> 
> 
> Kevin
> 
> On 11/28/05, Matt Hopcroft <hopcroft at snf.stanford.edu> wrote:
> >
> > Hello,
> >
> >        We've noticed increasing problems with the sts, and I'd like
> to
> > put some information out and get some feedback from other people
> who may
> > have been experiencing similar problems.
> >
> >        We've are etching 1 - 2 um wide trenches in SOI wafers with
> a 20
> > um device layer and stopping on the buried oxide. We have been
> doing
> > essentially the same type of etch since 2000. In the Fall of 2004,
> about
> > 12 months ago, we started having problems with the etch: footing,
> > mousebites, and incomplete etching. These results are illustrated
> in the
> > attached pdf. The problems are intermittent- results vary from day
> to day,
> > wafer to wafer, and across wafers, and over the last 12 months they
> have
> > become more frequent. We have tried all kinds of combinations of
> resists,
> > development cycles, pre-bake, post-bake, etc etc. Oxide hardmasks
> do seem
> > to reduce the mousebite problems; but why? And why now?
> >
> >        Is anybody else seeing these problems? Has anyone else
> noticed a
> > similar increase in problems in the past 12 months? Any thoughts
> are
> > appreciated. Thanks,
> >
> > -Matt Hopcroft
> > hopcroft at stanford.edu
> >
> >
> >
> 




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