[labnetwork] Flooring - ISO 5/6

Fri May 15 14:23:04 EDT 2015

Hi Everyone,

I agree with Bob that in a climate controlled lab where the humidity is constantly kept above 30% that ESD should not be a major concern.  Moving parts/materials between labs or spaces that do not have this type of control could cause problems.  The major concern to me is the cost of expensive ESD rated materials/installs to alleviate a problem that may not exist, but as a precaution always is included in the lab design/build.  

The only real problem I have seen in our lab may exist at our AFM.  There was some possible sticking of the tip to the sample while in a certain tapping measurement mode.  I was not convinced that it was ESD, but a spot ionizer from NRD did seem to cure the issue.  This was recommended by the AFM vendor. Types of problems such as this could be caused by high N2 purges across samples/surfaces or too high a laminar air flow causing localized charging.  Even with this stated, we did not see any ESD damage to the parts measured only difficulty with the measurement.  The AFM has a proper earth ground and we have a similar building ground to Berkeley which is much more elaborate than most installations.

Our flooring is a welded seam Armstrong Medintech product which is anti-static, but not a fully conductive floor, which from my past experience requires both conductive adhesive and copper strips tied to a proper earth ground placed beneath the floor.  The cost between anti-static and fully conductive flooring is large.  Expensive materials and install.  The last sentence answers another earlier flooring question from the mail list.  We have been satisfied with the Armstrong product, but some of the welded seams have split in high traffic areas, but we were able to repair.

I have yet to see a complete study done that is conclusive about ESD in research level cleanrooms, but have been told by many vendors that humidity control should take care of most ESD issues.  It may be that every space is different and may need POU control if determined to be a problem.  I may not incur many ESD problems in the UCSB lab now because of the materials used during construction so it is difficult to compare.

Cheers,  Tom

--------------------------------------------------------------

Tom Reynolds,  Lab Manager

UCSB Nanofabrication Facility

Electrical and Computer Engineering Dept.

Engineering Science Bldg #225, Room 1109E

Santa Barbara, CA 93106

805-893-3918 x215  office

805-451-3979  cell

805-893-3918  fax

reynolds at ece.ucsb.edu

From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Robert M. HAMILTON
Sent: Thursday, May 14, 2015 8:05 AM
To: Paul, Jack
Cc: labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] Flooring - ISO 5/6

Fab Colleagues,

I'd like to broaden the discussion of conductive floors and electrostatic discharge (ESD). I have trouble understanding how it is dealt with. At the outset, I have little experience with ESD as our lab is near the Pacific Ocean with moderate climate. ESD is less an issue for us than in the drier, colder parts of the US. However, given the climate controls in newer fabs it would seem ESD is less and issue within a fab than in the environs.

To use the lab our members and staff suit up with boots that are dielectric, shoe covers, gowns, caps and then nitrile gloves (we are aware some cleanroom garb is available from conductive materials). Noting this the gloves seem to be a "fly to the ointment" for ESD control. 

Example. Recently a lab member asked for replacement of ESD wrist straps at our wire bonders. My question is how much protection from ESD is had by a conductive bracelet if the ultimate garb is a pair of dielectric gloves? It seems gloves provide a barrier which acting for and against and ESD strategy. 

Although oblique to this discussion I'd like to mention we also have a robust ground-grid consisting of a flat 2" copper strap to provide excellent grounds for equipment, particularly rf enabled systems.

Of note, in a long history of semiconductor research we have not encountered device failures from ESD in our evolving lab environments. Having said this, the University of California Marvell NanoLab was built with conductive vinyl floors.

Regards,

Bob Hamilton

PS I'll digress a bit and share an story. The UC's anthropology library came to us some years back to find a way to neutralize the electrostatic force that bound ancient Egyptian papyrus to the plastic envelopes they were stored in. The papyrus was bound so tightly it tore before breaking loose. We introduced them to Ion Systems, specialist in ESD room control. Ion Systems came up with an effective solution to their problem.

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
http://nanolab.berkeley.edu/

On Wed, May 13, 2015 at 5:12 PM, Paul, Jack <Jack.Paul at hdrinc.com> wrote:

Greetings Loïk,

May I suggest a seamless resilient floor material (sheet vinyl with welded seams) in lieu of epoxy?

There are various sheet vinyl products available that can be installed less expensively than epoxy, and even more important, more easily repaired in an operational cleanroom environment.  

One product we have used successfully is Medintech, by Armstrong, which is a homogeneous sheet vinyl material that can be installed with heat-welded seams and has good chemical resistance as well as static conductivity.  There are other competing products that work just as well (this is by no means a sales pitch for Armstrong!).

Hope this helps.

Best regards,

Jack

-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Loïk GENCE
Sent: Tuesday, May 12, 2015 11:44 AM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Flooring - ISO 5/6

Dear All,

I would like to get some suggestions about of flooring for a small cleanroom ISO 5/6.

We are thinking about a dissipative epoxi flooring with copper tape for grounding.

Do you have some experience with this kind of flooring. Is there an alternative to epoxi?

Thank you for your comments.

Regards,

Loïk

--

__________________________________________

Dr. Loïk Gence

PUC-RIO/CETUC-LABSEM

End Rua Marques de São Vicente, 225-Gavea

CEP:22451-900   Rio de Janeiro, RJ-Brasil

       (Telefone)      +55 (021) 3527-2193 <tel:%2B55%20%28021%29%203527-2193> 

        (Mobile)     +55 (021) 99156-5558 <tel:%2B55%20%28021%29%2099156-5558> 

loik.gence at cetuc.puc-rio.br

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