Re: Cleaning the Chamber 3
Posted: Sun Sep 28, 2014 4:11 am
Water is, itself, a good solvent for many things. There is no issue with using 70% IPA and then doing a plasma clean. You should want to do a plasma clean anyway, it will break down all of those solvents, and any other greasy/oily droplets that might've found their way onto surfaces, and is a standard way for cleaning items in a clean lab (you wash in solvent, then plasma clean the item).
IPA's ~70% water content serves the medical application where the water content causes the skin pores to open up to assist cleaning the skin.
The principal reason for not using a lint cloth for cleaning is that you can get fibres across the vacuum connections, which may create leaks. I use 'regular' IPA wipes you get for industrial purposes and you pull 6" squares of the stuff from the top of a cylindrical dispenser. (I generally buy out-of-date stuff that may have dried up a little - no problem, just open the top and spray in a load of IPA!) These are 'lint free' but still tend to be a little fibrous, so after cleaning with that I will wipe down the seals with 1mm packing foam that I have sprayed IPA on to.
Cheap as chips.
Then to plasma clean you want to run around 100 to 1000 microns at 1000V with minimum current to get a glow discharge (AC is better, RF induction is what the lab plasma cleaners use) and leave it like that for 10 minutes or so, then switch off the plasma and pump down to sub micron for a few hours.
You will never get rid of all the adsorbed water before you close the chamber up, so there is little point in trying beyond ensuring it appearing visibly dry. Just plasma clean, and pump!
IPA's ~70% water content serves the medical application where the water content causes the skin pores to open up to assist cleaning the skin.
The principal reason for not using a lint cloth for cleaning is that you can get fibres across the vacuum connections, which may create leaks. I use 'regular' IPA wipes you get for industrial purposes and you pull 6" squares of the stuff from the top of a cylindrical dispenser. (I generally buy out-of-date stuff that may have dried up a little - no problem, just open the top and spray in a load of IPA!) These are 'lint free' but still tend to be a little fibrous, so after cleaning with that I will wipe down the seals with 1mm packing foam that I have sprayed IPA on to.
Cheap as chips.
Then to plasma clean you want to run around 100 to 1000 microns at 1000V with minimum current to get a glow discharge (AC is better, RF induction is what the lab plasma cleaners use) and leave it like that for 10 minutes or so, then switch off the plasma and pump down to sub micron for a few hours.
You will never get rid of all the adsorbed water before you close the chamber up, so there is little point in trying beyond ensuring it appearing visibly dry. Just plasma clean, and pump!