STS shower head thru etch effect
kenney at slac.stanford.edu
Tue Jul 5 10:54:31 PDT 2005
Sorry to over load all the STS users' mailboxes, but I've
attached an image of the tilt we observed. To set the scale
this is a 525 micron thick wafer and this image was
taken near the wafer's edge. As you can see the tilt angle
varied strongly with distance from the edge.
On Tue, 5 Jul 2005, Chris Kenney wrote:
> We also observed a shower-head effect several years ago on STS1
> and we thought it might be associated with use of the aluminum holder.
> Although we don't generally look for them, we haven't noticed tilted
> features before or since.
> Thanks for providing the references.
> On Tue, 5 Jul 2005, Jim McVittie wrote:
> > Jaime,
> > It sounds like you are seeing a charging effect. Back in the early 90's,
> > I did a bit of work on etch profile distortion due charging. We did
> > etching experiments, direct charging measurements and simulations. See
> > papers below. The work was done on one of the Dryteks for trenches
> > etched in the range of 5 to 10 deep. In general, charging is due to
> > plasma non-uniformity although the pattern on your wafer can have a
> > strong effect. In the Drytek case we used a magnet to cause plasma
> > non-uniformity. You are the first user to ever report this effect on
> > STS-1 so I suspect a temporary hardware problem could be the cause. Can
> > you give me more details on what you are seeing, such as how the tilt
> > varies across the wafer. Also are you seeing a lot of etch rate
> > non-uniformity.
> > Jim
> > S. Murakawa and J.P. McVittie, "Ion Trajectory Distortion and Profile
> > Tilt by Surface Charging in Plasma Etching", Appl. Phys. Letts., vol.
> > 64(12), pp.1558-1560, Mar., 1994.
> > S. Murakawa and J.P. McVittie, "Direct Measurement Of Surface Charging
> > Potential In Plasma Etching", Proceedings 2nd Intnl. Conf. Reactive
> > Plasmas, pp. 747-750, Jan. 1994, Yokohama, Japan, also in Jpn. J. Appl.
> > Phys., Vol. 33, pp. 4446-4449, Part 1, July 1994.
> > S. Murakawa and J.P. McVittie, "Mechanism of Surface Charging Effects on
> > Etching Profile Defects", Proceedings of Symp. on Dry Process ( IEE
> > Japan), pp. 39-44, Nov. 1993, Tokyo, Japan, also in Jpn. J. Appl.
> > Phys., Vol.33, pp.2184-2188, 1994.
> > jgarate at invensense.com wrote:
> > > Part 1.1 Type: Plain Text (text/plain)
> > > Encoding: 8bit
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