[labnetwork] Piranha processing vessels

Fri Apr 29 10:36:47 EDT 2016

Quartzware all the way!

Cheers!

Julia Aebersold, Ph.D.
Cleanroom Manager
Micro/Nano Technology Center
University of Louisville
Shumaker Research Building, Room 233
2210 South Brook Street
Louisville, KY  40292

502-852-1572
http://louisville.edu/micronano/

From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Robert M. HAMILTON
Sent: Thursday, April 28, 2016 4:21 PM
To: Keith Franklin <keithf at ualberta.ca>
Cc: Labnetwork <labnetwork at mtl.mit.edu>
Subject: Re: [labnetwork] Piranha processing vessels

Keith,

I'll stick my neck out!

The UC Berkeley NanoLab uses fused silica tanks with encased heaters and ground-fault detection for our piranha baths. I am guessing your suggestion of Pyrex or an alternative borosilicate glass will raise the hackles of some Labnetwork readers. And, I cannot claim experience with the impact of borosilicate glasses, used for piranha cleans, for MOS devices.

However, I can point to a patent issued to Alameda Instruments that made H2SO4 reclaim/reprocessing systems for a number of major semiconductor manufacturers. I also have known, since boyhood the research glassblower who made their vacuum stills. The glass used was Pyrex or an alternative Duran, which is Schott's equivalent. This leads me to the conclusion H2SO4 from a pyrex still was good enough for Intel, Pyrex is probably good enough for you.

Having said this if there is accidental contamination via HF your Pyrex will contribute alkali and your devices will be DOA. We have seen HF contamination in our baths on a few occasions.

For reference see:  https://www.google.com/patents/US4980032<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.google.com_patents_US4980032&d=AwMFaQ&c=SgMrq23dbjbGX6e0ZsSHgEZX6A4IAf1SO3AJ2bNrHlk&r=dinfzkbAbqkWVX3xF1fcv2PCcim1G4Oe9iPy5r31AUk&m=8qLrMDxvCESCZhAe4OsAWoJ3GWZ0motjIr9tjKVR6Ts&s=zlQU_MR8m65c1YuFcIQnrJ2MF4qyqh8_nKd47J3ml-0&e=>

Bob Hamilton

PS Caveat emptor! Corning now uses the term Pyrex for a broader number of glasses than their traditional 7740.

Robert Hamilton
University of CA, Berkeley
Marvell NanoLab Equipment Manager
Rm 520 Sutardja Dai Hall, MC 1754
Berkeley, CA 94720
Phone 510-809-8618 (desk - preferred)
Mobile 510-325-7557 (my personal mobile)
E-mail preferred: bob at eecs.berkeley.edu<mailto:bob at eecs.berkeley.edu>
http://nanolab.berkeley.edu/<https://urldefense.proofpoint.com/v2/url?u=http-3A__nanolab.berkeley.edu_&d=AwMFaQ&c=SgMrq23dbjbGX6e0ZsSHgEZX6A4IAf1SO3AJ2bNrHlk&r=dinfzkbAbqkWVX3xF1fcv2PCcim1G4Oe9iPy5r31AUk&m=8qLrMDxvCESCZhAe4OsAWoJ3GWZ0motjIr9tjKVR6Ts&s=W2jAw7UgPi3215VTj9D3eyW90TbFEljr0hZ3VVUEcx4&e=>

On Thu, Apr 28, 2016 at 10:59 AM, Keith Franklin <keithf at ualberta.ca<mailto:keithf at ualberta.ca>> wrote:
Good day all,

We're currently revisiting what vessels or tanks we use for processing with hot piranha.  Our most common application is for cleaning a partially filled cassette of 4" Si wafers.  We typically purchase Pyrex 6944 vessel and have our glass shop cut them down to a more reasonable height.  In our last purchase cycle, we noticed that the ID has changed ever so slightly and it's now challenging to squeeze our standard Entegris cassette into this vessel.  We're currently looking into custom machined PVC, PP,  Teflon & Quartzware, as well as off the shelf small volume tanks, etc.

I'm hoping to better understand what other similar labs are using for this application (& potentially 6" wafers as well).  Any advice or feedback would be greatly appreciated.

Kind Regards,
Keith

Keith Franklin

Operations Manager

University of Alberta - nanoFAB

W1-060 ECERF Building

9107 - 116 Street

Edmonton, Alberta

Canada T6G 2V4 Ph: 780-492-0170<tel:780-492-0170>
www.nanofab.ualberta.ca<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.nanofab.ualberta.ca&d=AwMFaQ&c=SgMrq23dbjbGX6e0ZsSHgEZX6A4IAf1SO3AJ2bNrHlk&r=dinfzkbAbqkWVX3xF1fcv2PCcim1G4Oe9iPy5r31AUk&m=8qLrMDxvCESCZhAe4OsAWoJ3GWZ0motjIr9tjKVR6Ts&s=BRDbMUfvY6S-C1g0gBrJsjrgUkyb_6gvq80zk_FHYVI&e=>

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