[labnetwork] Liquid Appearing in ICP Cl Chamber?!

[Martin, Michael]

Hi Emma,
   The only time we've had liquid in our etcher is when we were using Bcl3 delivered at around atmospheric pressure.  We now run it sub-atmospheric and have no problems.

  Curious to know how you guys are doing the digital log book.  Is this just an Excell sheet?  Is it part of PTIQ?  I would love to transition to something like this as opposed to paper based logs but fear that we would have even worse compliance than we already do.

-Michael
________________________________
From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Emma Anquillare <eanquillare at gc.cuny.edu>
Sent: Thursday, October 8, 2026 5:16 PM
To: labnetwork <labnetwork at mtl.mit.edu>
Subject: [labnetwork] Liquid Appearing in ICP Cl Chamber?!


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Dear Wise Lab Network Oracle,

I already shared this with a few tool managers and so far no one else has ever run into it, but maybe someone on here has:


Last week I went to vent and wet clean our ICP-Cl etcher. Our tool can only vent using Nitrogen, but I had recently become aware that it's considered a good practice to also then vent to atmosphere, so that if there are residues in the chamber that may react with atmospheric moisture to form HCl/HF vapors they can react fully and be pumped away before the chamber is opened. We don't have this capability, but to compensate I had started letting the tool sit in atmosphere for about an hour so (with a sign telling people to avoid the immediate area) so that even if any of these compounds had been present in unnoticeably small quantities, they could degas before I scrub it (wearing a full face respirator- we don't have a snorkel or air scrubber. That said, other technicians have previously been around this open chamber for days without a respirator and never mentioned any vapors or compounds.) The first time I added the hour wait, I did not notice anything unusual.

The last two times I opened the chamber, I've noticed small quantities of white solid on the lower crease of the metal rim. It's there when I first open the chamber, but then significantly reduces or disappears all together by the time the hour is up, so clearly it is reacting with something in the atmosphere. We have had white residue in the chamber before that XPS indicated was likely a fluoropolymer, but this has a very different look to it, and a fluoropolymer would not be so reactive (see attached photos).

Then, last time I went to clean the chamber, I came back after the hour in atmosphere to find not only had the white stuff reacted away, but liquid droplets had now formed on the metal ring beneath the liner a few inches away (See photos- though the entire metal ring appeared to also have a sheen to it- so I'm not sure if this was related or something new). The liquid was highly acidic (pH strip 0-1) , so we adjusted our clean to first wipe with a dry wipe, then water, and then only finished with IPA. The tool took longer than usual to pump down again (water on the O-ring?) but the next day it passed leak-up rate no problem.

Has anyone ever encountered a liquid in the chamber upon atmospheric exposure? (or ever?) Any idea what any of this might be? (A recent clip of the log is attached- though the 'element soup' method quickly turns into a very large number of potential compounds ). More importantly, If this happened to you, how might you adjust your safety and PPE practices accordingly?


Thanks!

(PS- A few years ago I shared our SOP for chamber wet cleans and mentioned using acid gloves. I recently realized IPA actually breaks through trionics fairly quickly (~25min), so for PPE I have now been using nitrile gloves on top of acid gloves, which seems effective.)
_____________________________________________
Emma Anquillare, PhD
Research Scientist
ASRC Nanofabrication Facility
City University of New York

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Catalyzing Change, Celebrating Gains:
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