[labnetwork] STS DRIE Multiplex Lip Seal failures

[N P VAMSI KRISHNA]

Hi Mark Weiler,
In my experience, the chamber O-rings should be Kalrez O-Rings, which can
withstand very high temperatures (white color O-ring). I request you to
check once if SPTS is supplying you the right one.
Please check all the 4 chamber heaters (inner wall, chamber, and others)
and confirm if the temperatures (~120 deg C) and the respective voltages
are within the spec. Maybe one of the heaters is getting a higher voltage.

Hope this helps.

Thanks and best regards,
vamsi


On Wed, Mar 6, 2019 at 6:11 AM Mark Weiler <mweiler at andrew.cmu.edu> wrote:

> Correction...
>
> In my haste to write something up and get out the door I mixed up the gas
> is in the problem description.
>
> Our process is typical Bosch SF6 and  O2 for etching .... switching off
> with C4F8 for passivation...
>
> Mark
>
> *Mark Weiler*
> Equipment & Facilities Manager
> Claire and John Bertucci Nanotechnology Laboratory
> Electrical and Computer Engineering | Carnegie Mellon University
> 5000 Forbes Ave., Pittsburgh, PA 15213-3890
> T: 412.268.2471 <412.268.5430>
> F: 412.268.3497
> www.ece.cmu.edu
> nanofab.ece.cmu.edu
>
> On Mar 5, 2019, at 18:42, Mark Weiler <mweiler at andrew.cmu.edu> wrote:
>
> Hello Everyone,
>
> We have gone through seven new lip seals purchased form Orbotech/SPTS.
> They are often failing before we even finish qualifying the system, or
> within a month thereafter.
>
> Our our process is stable with power and parameters not deviating over the
> past decade.  However, I ordered the most recent batch of lip seals because
> the wafer seals we had been using were coming out with black residue after
> only a few runs… however, the current ones do the same.  Not only have the
> lips seals disintegrated, but the chamber lid o-ring and bottom ceramic
> spool o-ring have also failed with black rubber material shedding off.
> It’s as if they are made of Buna and not meant for this application.
>
> Our process is typical Bosch with 100 sccm C4F8 and 20 sccm O2 for etching
> switching off with ~50 Sccm SF6 for passivation at a processing pressure of
> 15 mTorr, Coil power 600-800W,  Platen power 100-150W, Bias voltage 50-100v
> (up to 200 peak-to-peak), Platen temp at 19 degrees, Lid temp 41 degrees.
> Qual wafers are new bare Silicon.  Etch rates are normal and stable with
> 10+ years of data…. we just can’t complete the work due to failing seals.
>
> Our chamber base pressure is between 1E-8 and 5E-8 Torr each morning.
> When we put in a brand new seal and run only the LUR, it passes with 0.00
> mTorr/minute leak rate.  That jumps to 3.00 mTorr/m after only 30 minutes
> of the SPTS recommended O2 Clean… then rises as time and more runs
> progress.  Wafers are coming out with black rings on their backsides.
>
> This should not be happening, and I believe it is due to incorrect
> material of the lip seals and o-rings.  I am pinging the network, though,
> to see if there might be a parameter change we need to effect that may
> assist us.
>
> Have any of you seen this before?
>
> Best regards,
>
> Mark
>
>
> ________________________________________________________________
>
> Mark Weiler
> Equipment & Facilites Manager
> Clair and John Bertucci Nanotechnology Laboratory
> Eden Hall Nanofabrication Cleanroom
> Carnegie Mellon University
> P:  412-268-2471
> http://www.nanofab.ece.cmu.edu
>
>
> <https://www.linkedin.com/in/marksbasics>
> <https://www.linkedin.com/in/marksbasics>
>
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-- 
--
Thanks & Best Regards,
-----------------
*N.P.Vamsi Krishna*
3D Heterogeneous Integration and System Scaling Lab,
Center for Nano Science and Engineering (CeNSE),
Indian Institute of Science(IISc), Bangalore.
INDIA-560012
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