[labnetwork] Flooded ICP-RIE

[Stephen Howe]

Dear Peter,

Not sure exactly which model you have, but I am a broker and I just
bought an STS 320 PC R.I.E. from a lab here in Italy for re-sale.

You might possibly be able to purchase it from me for spares use if you
have the same model:-

https://www.fabsurplus.com/sdi_catalog/salesItemDetails.do?id=79584
SDI ID: 	79584
Manufacturer: 	STS
Model: 	320 PC
Description: 	Reactive Ion Etcher
Version: 	200 mm
Vintage: 	01.06.1995

I recall we almost had the same kind of incident 25 years ago when I was
working for Micromass in Manchester. A workman re-did our lab water
supply and "helpfully" connected up the water to the house vac. and the
house vac. to the water. But, luckily, my collegue double checked the
connections before the workman opened the taps and averted the disaster
before it occurred...

Yours sincerely,

Stephen Howe 
Company Owner
SDI Fabsurplus Group

+1 830 388 1071 (Mobile)

Skype: Stephencshowe
email: info at fabsurplus.com

WWW.FABSURPLUS.COM

On Mon, 2016-08-22 at 08:15 +0000, Peter Köllensperger wrote:
> 
> 
> Dear Labnetwork Members,
> 
>  
> 
> I’ve just recently started as process group leader here at NTNU
> NanoLab in Trondheim, Norway, but have been following the discussions
> on the mailing list with interest.
> 
>  
> 
> I now have a question of my own and would very much appreciate any
> thoughts or advice you may be able to share.
> 
>  
> 
> We are currently having preventive maintenance of our ICP-RIE systems
> carried out by the manufacturer.
> 
> Unfortunately one of their engineers mixed up the helium backing line
> with the coolant line from the chiller unit. When the chiller was
> switched on, it pumped ca. 1-2 litres of a water and Hexid heat
> transfer fluid into the main chamber and loadlock. The system was not
> under vacuum at the time. The RIE section was completely filled with
> water and the main chamber also had water in it.  The lifting pins
> assembly including bellows, the CM gauge the pirani gauge as well as
> the He line were completely submerged.
> 
> The engineers realised what was going on after the chiller gave a low
> level alarm and they saw the coolant level continue to drop. They
> stopped the chiller, opened the chamber, and mopped up the liquid with
> PIG pads and cleanroom cloths where accessible. They then switched on
> both the roughing and loadlock pump.
> 
> When the loadlock pump was switched on it died immediately. They
> realised that water vapour shouldn’t enter the scrubber and removed
> the exhaust line from the scrubber, but it is likely that some water
> vapour ++ entered the scrubber as steam was coming out of the exhaust.
> This means the entire system has been exposed to water/coolant mix,
> possibly with exception of the turbo pump, although there may have
> been some backstreaming from the main roughing pump.
> 
>  
> 
> Pumping the chamber from Thursday to the following Tuesday improved
> the vacuum from 1x10e-2 Torr with a leakup rate of 20 mTorr/min to
> 5x10e-5 Torr with a leakup rate of 5 mTorr/min. Specification is less
> than 1 mTorr/min.
> 
>  
> 
> Needless to say this causes a number of issues, some of which we may
> not even have thought to consider.
> 
>  
> 
> In our view, the issues can be divided into immediate Health and
> Safety concerns, and more long term concerns regarding the performance
> of an ICP RIE unit that has been flooded
> 
>  
> 
> 1.       Regarding H&S issues we’re concerned about are the mixing
> of SF6, CHF3, Cl2 and BCl3 with water in the scrubber.
> 
> We will send the scrubber for a refill and check. We have contacted
> the vendor of the scrubber, his main concern is clogging of the
> granulate. Is there anything else we should pay attention to?
> 
>  
> 
> 2.       Can a chamber be sufficiently reconditioned by in situ by
> cleaning, baking and running plasmas or will the coolant inside
> necessitate a more complete disassembly and clean?
> 
> Has anyone had a similar problem and how did you proceed? How would
> you suggest we ask the manufacturer to verify that there are no
> long-term detrimental effects on the instrument, the pumps or the
> processes run on the instrument?
> 
>  
> 
>  
> 
> I'd appreciate any thoughts you may have surrounding this issue. 
> 
> 
> Kind regards,
> 
>  
> 
> Peter
> 
> 
> 
> 
> 
> 
> 
> ––––––––––––––––––––––––––––––––––––––––––––––
> 
> 
> Dr. Peter A. Köllensperger
> NTNU NanoLab
> Sem Sælandsvei 14
> Norwegian University of Science and Technology (NTNU)
> 7491 Trondheim
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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