[labnetwork] RIE Process Gases

[Cenk Yanik (Alumni)]

Dear Matt,
Thank you ( for a comprehensive reply) and everyone for sharing the details.
Best Regards,

Matthew Moneck <mmoneck at andrew.cmu.edu>, 9 Eki 2019 Çar, 21:19 tarihinde
şunu yazdı:

> Hi Cenk,
>
>
>
> We try to run ours to a low point, but not quite empty if we can.  For
> example, we typically run 2000psi cylinders to 200psi then swap the bottle.
> For lower pressure cylinders or liquid cylinders measured by weight, we
> still tend to use that 10% mark as a changeout point, although,
> admittedly, some cylinders do inadvertently run to complete empty.
>
>
>
> That said, cylinders do have a shelf life and most university
> Environmental Health and Safety groups have their own recommendations on
> what they consider acceptable.  Many of the semi grade gases “expire”
> within 3 years.  We have gone well beyond this without any noticeable
> change in our processes.  However, you have to pay attention to the
> cylinder itself.  There is a stamped certification date typically
> imprinted at the top of the cylinder.  This is the date on which the
> cylinder underwent hydrostatic testing and certification.  Most high
> pressure gas cylinders are rated 10yrs beyond that date.  If you have a
> cylinder that is approaching the 10yr mark, send it back (note that your
> cylinder may not have been filled in year 1, so do not assume that it’s
> 10yrs past the fill date).
>
>
>
> For Cl and other corrosive gases, I believe the limit is typically 5yrs
> for the cylinder, although, I would need to check that to be 100% sure.  We
> tend to swap ours out within 2yrs.  You also have to watch for cylinders
> containing gases that react with the cylinder material itself.  For
> instance, anhydrous HF used in vapor HF systems can be purchased in steel
> (i.e. iron) cylinders.  At the time of purchase, the cylinder pressure is
> only a couple psi or so.  However, if you hold on to one of these bottles
> for too long, the HF can react with Fe to release hydrogen, causing the
> cylinder to overpressurize and possibly explode.  It is typically
> recommended to exchange such cylinder within 2yrs.  For that reason, we
> use nickel cylinders on this material and still follow the 2yr rule.
>
>
>
> Best Regards,
>
>
> Matt
>
>
>
> --
> *Matthew T. Moneck, Ph.D.*
> Executive Manager, Claire & John Bertucci Nanotechnology Laboratory
> Electrical and Computer Engineering | Carnegie Mellon University
> 5000 Forbes Ave., Pittsburgh, PA 15213-3890
> T: 412.268.5430
> F: 412.268.3497
> www.ece.cmu.edu
> nanofab.ece.cmu.edu
>
>
>
> *From:* labnetwork-bounces at mtl.mit.edu [mailto:
> labnetwork-bounces at mtl.mit.edu] *On Behalf Of *Cenk Yanik (Alumni)
> *Sent:* Wednesday, October 09, 2019 2:59 AM
> *To:* labnetwork at mtl.mit.edu
> *Subject:* [labnetwork] RIE Process Gases
>
>
>
> Dear All,
>
> We are wondering how often do you change the RIE process gases even the
> gases are not run out. We have been told that they should be changed in max
> 3 years even if they are almost full but we have been using some of them
> (SF6, C4F8, CHF3)  for 5 years and we didn't realize any process-related
> critical problems during the dry etching process.
>
> Have you ever faced with any problems for Fluorine and Chlorine based
> gases in your institutes?
>
> We would appreciate if you could share your experiences and regulations
> considering the shell life of the process gases at your facilities
>
> Best Regards,
>
>
>
> --
>
>
> Cenk YANIK, PhD
>
> Nanofabrication Team Leader
>
> Sabanci University
> Nanotechnology Research and Application Center ( SUNUM )
> Orta Mahalle, Üniversite Caddesi No: 27 34956 Tuzla - İstanbul
> Office:+90 216 483 9994
> web: sunum.sabanciuniv.edu
>


-- 

Cenk YANIK, PhD
Nanofabrication Team Leader

Sabanci University
Nanotechnology Research and Application Center ( SUNUM )
Orta Mahalle, Üniversite Caddesi No: 27 34956 Tuzla - İstanbul
Office:+90 216 483 9994
web: sunum.sabanciuniv.edu
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