[labnetwork] Deep Reactive Ion Etch Problems

[N P VAMSI KRISHNA]

Hi Pallavi,
If all of a sudden you are seeing grass in all the recipes (without any
open chamber repairs):
1. Do long oxygen clean: This will help you in removing excess polymer on
the chuck or any metal contamination in the chamber. Observe the plasma for
any sparks or fluctuations in Vpp or DcBias.
2. Use your standard recipe and try increasing platen temperature. Inspect
your platen temperature.
3. Check the condition of ESC for any black spots or particles (open
chamber).

If there is any change in the chamber conditions like recently AMC done or
ESC replacement?  The picture below might help you tuning the recipe.
1. First I would try increasing the platen temperature (In most of the
cases this will work)
2. Then try to reduce polymer flow. If there is a change in profile,
increase it.
[image: Screen Shot 2020-07-27 at 4.47.23 PM.png]
Hope this helps.

Thanks & Regards,
Vamsi


On Mon, Jul 27, 2020 at 2:53 PM Pallavi Sharma <pnsharma at unm.edu> wrote:

> Hello all,
>
> I am having problem with anisotropic etching of silicon by Deep Reactive
> ion etch. Grass or black silicon is the issue all the time, attaching some
> of the SEM pictures of the sample. Every recipe I tried to fine tune result
> in grass formation, even as the process initiates in tool wafer surface
> starts to turn brown and ultimately black. I tried varying SF6 gas flow,
> Bias power, Substrate temperature but every time I see is highly dense
> grass with no clean surface.
> Any help will be greatly appreciated.
>
> Thank you,
> Pallavi
>
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-- 

___________________________________________________

N.P.  Vamsi Krishna, PhD

Postdoctoral Fellow

Pritzker School of Molecular Engineering, *The University of Chicago *

Center for Nanoscale Materials, *Argonne National Laboratory *

Phone: 1 (331) 757-8565
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