[labnetwork] STS DRIE Multiplex Lip Seal failures

Wed Mar 6 17:01:22 EST 2019

If you are seeking an alternate supplier of improved o-rings,
Berkeley NanoLab has had good experience with the cost competitive
and Kalrez equivalent products offered by FloDynamix.
Their FFKM versions "Kratos" and "Gumlast" have served us well
in several applications.

Bill Flounders
UC Berkeley NanoLab

On Wed, Mar 6, 2019 at 1:56 PM Mark Weiler <mweiler at andrew.cmu.edu> wrote:

>  Hi David,
>
> I am currently working with an elastomer manufacturer to produce O-Rings
> and seals for the systems of a material that can withstand better
> temperature ranges and chemical attacks.  If you would like, I can share
> the information with you and maybe you can join us in this endeavor.  The
> cost for the tooling and mold is now at ~1900 dollars, but I have
> negotiated the seal price to around 130.00 ea.  I have not yet tested this
> material but we are having a seal made specifically for the Bosch process
> and 02 cleans.
>
> It is my believe that Orbotech has changed suppliers, or has allowed their
> supplier to switch their material source without testing, all in an effort
> to shave costs.
>
> My new efforts have also yielded a lower cost (50%) for the ceramic
> components in the chamber.  I will test these and get back with the lab
> network sharing the source and part number.
>
> Thank you for sharing your info; now I know we are not the only ones
> “feeling the pain” so to speak and can officially commiserate... LOL
>
> Best,
>
> 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 6, 2019, at 08:46, LaFleur, David W <dlafleur at cns.fas.harvard.edu>
> wrote:
>
> Hi Mark,
>
>
>
> We have an STS MP0579 ICP which uses the lip seals. It is used mostly for
> silicon and SiO2 etches with O2 cleans between uses. Most of our Bosch
> processes are run on SPTS Rapier which uses an ESC. That has its own set of
> issues. We find the lip seals don’t last more than 2-3 weeks in our system.
> Our chamber o-rings usually go for 2 months at best. I was thinking of
> changing to a kalrez o-ring and always wondered if they made a Kalrez lip
> seal. One suggestion on how to make them last longer is make sure they
> don’t get exposed to any solvents like Isopropyl when you are installing
> them. I want to say I am not happy with the longevity of the lip seals
> either and maybe we need to bring this to the attention of Orbotech/SPTS.
> Maybe they have a solution. Other than that they are good tools, very
> reliable, and heavily used here at Harvard. Because they are so heavily
> used with so many processes we find a biweekly chamber clean and lip seal
> replacement works well for everyone. This is why I have just lived with the
> lip seals as they are.
>
>
>
> Regards,
>
>
>
> David LaFleur
>
> Equipment Engineer
>
> CNS, Harvard University
>
>
>
> *From: *"labnetwork-bounces at mtl.mit.edu" <labnetwork-bounces at mtl.mit.edu>
> on behalf of Mark Weiler <mweiler at andrew.cmu.edu>
> *Date: *Tuesday, March 5, 2019 at 3:44 PM
> *To: *Fab Network <labnetwork at mtl.mit.edu>
> *Subject: *[labnetwork] STS DRIE Multiplex Lip Seal failures
>
>
>
> 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
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