[labnetwork] Deep Reactive Ion Etch Problems

[Matthias Pleil]

Thank you for all of your input, Pallavi and I ran a wafer with the passivation cycle off (SF6 only, no C4F8) - no grass.  The grass must be coming from the passivation step, so she is going to run a series of experiments progressively increasing the passivation cycle to see when grass starts to grow.

Kind Regards,

Matthias Pleil, Ph.D.
Research Professor & Senior Lecturer III of Mech. Eng - UNM
UNM MTTC Cleanroom Manager
PI - Support Center for Microsystems Education
Find great curriculum at: www.scme-support.org<http://www.scme-support.org/>
(505)272-7157

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[cid:065de0b5-43f6-48c8-bfda-05f5b170da28]



________________________________
From: labnetwork-bounces at mtl.mit.edu <labnetwork-bounces at mtl.mit.edu> on behalf of Zhang, Jessie (Fed) <chen.zhang at nist.gov>
Sent: Wednesday, July 29, 2020 9:02 AM
To: Beall, James A. (Fed) <james.beall at nist.gov>; Pallavi Sharma <pnsharma at unm.edu>; labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
Subject: Re: [labnetwork] Deep Reactive Ion Etch Problems


  [EXTERNAL]

Agree with Jim. If after chamber clean and reconditioning, the problem still exists, check all the MFC and make sure there is no leak and calibrated. We ended up replaced one of the MFCs last spring to end the battle with black silicon on our Unaxis DSE.



Jessie





From: labnetwork-bounces at mtl.mit.edu <labnetwork-bounces at mtl.mit.edu> On Behalf Of Beall, James A. (Fed)
Sent: Monday, July 27, 2020 4:52 PM
To: Pallavi Sharma <pnsharma at unm.edu>; labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] Deep Reactive Ion Etch Problems



When we see that it often means you are overdue for chamber cleaning and reconditioning.

For us (SPTS Pegasus 150 mm tool) that is a long O2 chamber clean with a wafer on the chuck) followed by running our standard Bosch process on bare silicon full wafers until they come out shiny.

If that fails then you need manual chamber wall clean (iso and scotchbrite) followed by the above.



Best of luck,



Jim

________________________________

From: labnetwork-bounces at mtl.mit.edu<mailto:labnetwork-bounces at mtl.mit.edu> <labnetwork-bounces at mtl.mit.edu<mailto:labnetwork-bounces at mtl.mit.edu>> on behalf of Pallavi Sharma <pnsharma at unm.edu<mailto:pnsharma at unm.edu>>
Sent: Monday, July 27, 2020 10:02 AM
To: labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu> <labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu>>
Subject: [labnetwork] Deep Reactive Ion Etch Problems



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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