[labnetwork] Plumbing new gases in ICP-RIE gas pod

[Paolini, Steven]

Kevin,
  What you have is an early version of a gas pod that is capable of handling two flammable/toxic/pyrophoric gases. On the SF6 and CF4 channels, you have pneumatic two way shut offs that are upstream and downstream of the MFC. The manual toggle valve is there as a bypass to purge the circuit should the MFC fail and you lose your means of evacuating and purging for replacement. This is overkill for the gases you intend to run. 
The output lines are separate with O2 and N2 going to one line to the machine and the other one is for the reactive gases which, I presume, were toxic when the machine was commissioned. This arrangement was most likely set up to keep the nasty gas separated from the O2  as far away and remix as close to the chamber as possible.
  Steve Paolini   Equipment Dood
  Harvard University Center for Nanoscale Systems.

Steve Paolini
Principal Equipment Engineer
Harvard University Center for Nanoscale Systems
11 Oxford St.
Cambridge, MA 02138
617- 496- 9816
spaolini at cns.fas.harvard.edu
www.cns.fas.harvard.edu

-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu <labnetwork-bounces at mtl.mit.edu> On Behalf Of Kevin M McPeak
Sent: Thursday, January 23, 2020 8:42 AM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Plumbing new gases in ICP-RIE gas pod

Dear Colleagues,

Here at LSU, we want to add C4F8 and CHF3 gases to our Oxford ICP100 system. The gas pod (see attached photo) currently has the following gases plumbed from top to bottom: O2, N2, CF4, and SF6. Notice, the current CF4 and SF6 lines have additional valves and plumbing. 

When I add the C4F8 and CHF3 do you recommend I plumb them like the O2 and N2 gases (filter -> MFC -> valve) are or do I need to add the additional valves and plumbing like the SF6 and CF8 lines are? We can do either but the SF6/CF4 method is a lot more money and time. This is an old gas pod, circa 1995 and Oxford has limited information. and advice. 

NOTE: The two output lines (top line and 3rd from top) from the gas pod get merged at the tool before entering the instrument. I am not sure why it was plumbed this way back in 1995.

Regards,
Kevin

--
Kevin M. McPeak
Assistant Professor | LSU Dept. of Chemical Engineering
225-578-0058 | mcpeaklab.com | lsu.edu/nanofabrication