[labnetwork] BCL3 - Gas Line Heaters and Protocols

[Tom Reynolds]

I agree with Bob and Steve.  This is our approach at UCSB with our BCl3. We
feed multiple tools from one source with over 100' of 1/4" SS coax line.
Keep the cylinder pressure as low as possible with a sub atmospheric
regulator while maintaining the appropriate total flow. This took us a
little time to figure out originally as we set up the lab, but has worked
fine since the adjustments.
--------------------------------------------------------------
Tom Reynolds,  Lab Manager
UCSB Nanofabrication Facility
Electrical and Computer Engineering Dept.
Engineering Science Bldg #225, Room 1109E
Santa Barbara, CA 93106
805-893-3918 x215  office
805-451-3979  cell
805-893-3918  fax
reynolds at ece.ucsb.edu




-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu]
On Behalf Of Paolini, Steven
Sent: Tuesday, August 27, 2013 7:57 AM
To: Dean Sutter; <labnetwork at mtl.mit.edu>
Cc: Rose, Robert W; Michael Sullivan; Vinh Nguyen
Subject: Re: [labnetwork] BCL3 - Gas Line Heaters and Protocols

I agree with Bob Hamilton. I have gone through all the problems associated
with low vapor pressure liquid source gases and the only method that has
worked flawlessly for me is to lower the delivery pressure to keep the
material in vapor form. This is a common problem with gases such as Boron
Trichloride and Dichlorosilane.  In the past, we have heated lines,
cylinders, and any other object in the gas circuitry in an effort to keep
the gas from condensing into liquid but the material always finds something
cooler (like an MFC) and it results in condensation problems. Good ole' high
school physics tells us if you lower the pressure surrounding a liquid, you
lower the boiling point proportionally.  I now purchase sub-atmospheric
regulators and run these gases at the lowest possible pressure that will
still deliver full flow and then add about 10% more. Typical pressures for
Dichlorosilane are around 1 in Hg to 1 PSI and for Boron Trichloride about 3
PSI due to the higher flows u  sed. Luckily, these gases are almost always
used in a vacuum system.
Steve Paolini
Equipment Dood
Harvard University Center For Nanoscale Systems

-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu]
On Behalf Of Dean Sutter
Sent: Monday, August 26, 2013 3:10 PM
To: <labnetwork at mtl.mit.edu>
Cc: Rose, Robert W; Michael Sullivan; Vinh Nguyen
Subject: [labnetwork] BCL3 - Gas Line Heaters and Protocols

Hello,

AT GT Nano we have a hard plumbed BCL3 line coming from a central gas room,
running several hundred feet into the sub fab eventually connecting to the
tools.

We have been internally debating the necessary protocols and physical
installations necessary  to ensure a safe and properly functioning delivery
mechanism.

These discussions have included the elimination of the central approach,
replaced with a local gas cabinet and shorter runs since maintaining and
being able to monitor line heaters on a several hundred foot of line, buried
in plumbing up in the ceiling  is our primary concern.

So, we are seeking a benchmark from existing facilities that use BCL3.

Anyone care to volunteer to explain their installation and operating/safety
protocols?

Thanks

--
Dean A. Sutter
Associate Director,
Research Operations and Industry Engagements

dean.sutter at ien.gatech.edu
404 894 3847 - Office
404 558 1844 - Cell
www.ien.gatech.edu



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