Plasma Cleaning

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George Schmermund
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Plasma Cleaning

Post by George Schmermund » Mon Dec 16, 2013 10:02 pm

Here's an interesting video about plasma cleaning. Ben has some of the best hacker projects on YouTube. I'd be concerned with pumping pure O2 through a hot DP and anything less than Fomblin oil in the mechanical pump, though!

http://www.youtube.com/watch?v=atVSxvbiPg0
Anything obvious in high vacuum is probably wrong.

John Futter
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Re: Plasma Cleaning

Post by John Futter » Tue Dec 17, 2013 6:08 am

Well said George

pumping pure oxygen through a mechanical pump is asking for a fierce fire in the pump or pump outlet.
Air is more than OK 19% oxygen and is used all over.
Argon is even better as the molecule is heavier --this is why argon is used in gold coaters for SEM work.
So an SEM coater with an aluminium target will act as a cleaner as the Aluminium doesn't sputter well at the voltages used in these cleaners
We tend to accelerate argon ions to around 15kV to maximise the sputtering effect to clean surfaces before PVD or EVAP processes. the sputtering is selective ie light contaminents get removed before host material atoms so timing is important
Xenon would be better but it is eye watering expensive

all for now

ChrisJ
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Re: Plasma Cleaning

Post by ChrisJ » Thu May 28, 2015 3:15 pm

Have you considered purchasing an oxygen safe pump from a plasma cleaner Manufacturer? I am considering the purchase of a plasma cleaner, most specifically, looking at reactive ion etching systems but I need an oxygen safe vacuum pump. The pumps are expensive, has anyone used one before?

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Frank Sanns
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Re: Plasma Cleaning

Post by Frank Sanns » Sun May 31, 2015 8:13 pm

I don't see the need for any special pumps for plasma cleaning of a fusor or any small chamber. The ultimate pressure for glow cleaning is on the order of 100 mTorr. There is no need for any significant flow rate so there would be not more oxygen going through than there would be in a chamber that was pumping down to 500 motor.

We were plasma cleaning some polymers to enhance adhesion and we just used air and a standard 2 stage pump with good success.

prestonbarrows
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Re: Plasma Cleaning

Post by prestonbarrows » Sun May 31, 2015 9:52 pm

On small scale amateur work, you don't need any special vacuum pumps for oxygen plasmas. The ballpark inlet flow rate is only on the order of 10's of SCCM. You push more oxygen through during initial pump down of the chamber from atmosphere.

Jerry Biehler
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Re: Plasma Cleaning

Post by Jerry Biehler » Mon Jun 01, 2015 3:58 am

And most diff pumps are running one of the silicone oil and they are not flammable.

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