[labnetwork] HF storage

Thu Feb 23 09:56:50 EST 2023

At Rochester Institute of Technology we have designated HF baths of various water to HF ratios (50:1, 10:1 etc.) that are on certain dedicated benches.
The baths are only changed on the normal schedule or when the etch rate monitors indicate a change, or there is some contamination suspected.
No students (or faculty) can access the 49% HF used to change the baths, it is only done by staff.

Rob Pearson,
RIT Microelectronic Engineering.

From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Michael Yakimov
Sent: Thursday, February 23, 2023 9:08 AM
To: Savitha P <savithap at iisc.ac.in>; labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] HF storage

One issue with "automatic removal of access":
punitive measures are not the best if safety is involved. Especially for minor things, where user may have a small event that didn't lead to serious consequences - but the user may share the problem, get some advice, and some things may improve after all. If user is discouraged from that by automatic punishment, then things work worse overall.

It's a big philosophic question in general but looks like safety actually benefits from a less punishing approach.  Of course, such dilemmas go well beyond cleanroom or chemical safety and experience comes from many industries. I heard a lot of such discussions in aviation safety - and I would call that even more safety-critical business than what we're doing...

Thanks

Mike

_______________________________________________

Michael Yakimov

Research scientist

College of Nanoscale Science and Engineering

SUNY Polytechnic Institute

253 Fuller rd.

Albany NY 12203

Phone: 518-437-8609 lab

e-mail: yakimom at sunypoly.edu<mailto:yakimom at sunypoly.edu>

________________________________
From: labnetwork <labnetwork-bounces at mtl.mit.edu<mailto:labnetwork-bounces at mtl.mit.edu>> on behalf of Savitha P <savithap at iisc.ac.in<mailto:savithap at iisc.ac.in>>
Sent: Thursday, February 23, 2023 3:32 AM
To: labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu> <labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu>>
Subject: Re: [labnetwork] HF storage

Dear All:

Thank you very much for all the suggestions. We have currently incorporated the following as per our space availability.  HF has been segregated and kept in a secondary container so that users will not mistake the same with HCl. Size of Labels on the bottles have been increased for HF only, so that users have another mark for identification.  As per our protocol, all safety incidents at wet etch leads to an automatic removal of access to the cleanroom. The user will be allowed only after a retraining and retest and will be provided access only after a satisfactory drive in.

Regards,
Savitha
________________________________
From: Jing Guo <jeanne.guo at rice.edu<mailto:jeanne.guo at rice.edu>>
Sent: 16 February 2023 21:41
To: Savitha P <savithap at iisc.ac.in<mailto:savithap at iisc.ac.in>>
Cc: labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu> <labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu>>
Subject: Re: [labnetwork] HF storage

External Email

Hi Savitha,

This is Jing from Rice U Nanofab. Fortunately we have enough space to store HF or BOE in a separate cabinet. HCl is stored with the other acids in the 'General Acids' cabinet. Also all HF related processes will be performed in the separate HF wet bench which is a independent bench from other benches. For all of our chemicals, we are using the 'Two-letter' labelling system which I learned from Utah NanoFab a long time ago. All chemical bottles, storage cabinets and wet benches have a 'two letter' sticker on. All HF bottles have the 'HF' stickers. HCl or other Acids have the 'GA' stickers (general acid). The stickers have to match to the cabinets and benches when you need to store or use them.

For very limited lab or storage space, the simple solution I can think about will be separate secondary containers with different colors, and put different color stickers on the bottle caps. Also put a big color chart beside the storage cabinets and benches to clarify which is which.

I totally agree with Tony, no matter how great foolproof your system is, there will still be someone making mistakes. Wish our system can provide some idea to help.

Best,
Jing
---------------------------------------
Jing Guo Ph.D.
Research Scientist
SEA Cleanroom (SST 017)
Rice University
Houston, TX
jeanne.guo at rice.edu<mailto:jeanne.guo at rice.edu>
713-348-8227

On Feb 15, 2023, at 6:19 AM, Savitha P <savithap at iisc.ac.in<mailto:savithap at iisc.ac.in>> wrote:

Hi!

We recently had a couple of occasions where users had mistakenly used Hydrofluoric acid in place of Hydrochloric acid during RCA cleaning. To avoid this, one of the suggestions we have received from our OLSEH is to store HF in a different coloured bottle (currently all acids are stored in white translucent polypropylene bottles which are properly labelled). Accordingly, we had considered storing HF in opaque, brown colour HDPE bottles. However, that was not deemed acceptable by a section of users saying bottles should be translucent so that acid level inside can be judged.

Could you please let me know how small quantities of HF are stored in your respective fabs. Is there any regulation governing storage of HF, so that we could implement the same.

Thanks and regards,
Savitha

Dr. Savitha P
Chief Operating Officer
National Nanofabrication Centre
Centre for Nanoscience and Engineering
Indian Institute of Science
Bangalore - 560012
India.
Ph. +91 80 2293 3319
www.cense.iisc.ac.in<https://urldefense.com/v3/__http:/www.cense.iisc.ac.in__;!!BuQPrrmRaQ!jwbzV_ZvSyB1Q5acEoqn2bdk1V1F959zmmHlnmL0yfvnJJ7KjK-9pQMpfGdp8hSSHKhA-Mmu9UAZSVxRNrPjWiAe3he9vQ$>
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