[labnetwork] Flooded ICP-RIE

[N P VAMSI KRISHNA]

​Dear Peter,
We had a similar issue in one of the our tool AMC's long back. A Field
Service guy messed up the He and the Chiller fluid line, and a considerable
amount of chiller fluid (Julabo Chiller) ​went in the chamber. I do agree
with the Steve Paolini, Tom Britton and Rich Morrison’s inputs.

I remember we changed all the o-rings which went in contact with the fluid.
Removed the platen and load lock bellows. Did extensive wet clean of all
the parts and bellows. Flushed all the contaminated lines and chamber with
huge amount of N2. Chamber liners we did a mechanical scrub. Some of the
metal components we baked them in an oven for some time before we reinstall
them.

Took almost a week for regular vacuum and LUR. Did long O2 plasma cleans
and checked all the recipes for deviation in plasma color or etch rates and
profiles.

Best of luck,


Thanks & best regards,
vamsi

On Mon, Aug 22, 2016 at 1:45 PM, Peter Köllensperger <
p.kollensperger at ntnu.no> 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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>
>


-- 
--
Thanks & Best Regards,
-----------------
*N.P.Vamsi Krishna*
​National Nano Fabrication Centre,

Center for Nano Science and Engineering (CeNSE),
Indian Institute of Science(IISc), Bangalore.
INDIA-560012

“Educating the mind without educating the heart is no education at all.”
-Aristotle
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