[labnetwork] Nitrogen Purity for Sputtering

[Mark Heiden]

We are moving a sputtering system from a remote installation into our cleanroom and the intent has been to take it "off the bottle" and use the building process nitrogen system for process gas as well as venting. The bottles on the old install were 99.999% but the building process nitrogen is not certified to any exact number. The piping comes out of the 9000 gal. tank and through a vaporizer, then it goes through filters then splits into "house" nitrogen which is copper piping and "process" nitrogen which is all stainless steel with 10ra polished inside.

>From the stainless building process nitrogen line regulator, we ran high purity Teflon PFA tubing to the point of use filter on the MFC. Since I can't provide a precise purity for the evaporated nitrogen gas coming from the bulk tank and the tubing from the regulator to the filters is not stainless, a PI that was using the system is terrified that the nitrogen won't be pure enough. Could I get your opinions on what the purity may be expected to be and if it is less than 99.999% would the filters correct this anyway?

I'm sure most operations that spent the money for a "process" nitrogen system are not then running everything on bottles anyway so how do you ensure that the nitrogen being delivered to the systems is pure enough?

Thanks in advance,


Mark Heiden
NanoFab Cleanroom Manager
Center for Nanoscale Science and Engineering
University of California, Riverside
951-827-2551


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