[labnetwork] Flooring - ISO 5/6

Thu May 14 12:14:19 EDT 2015

Hi All,

At Draper laboratory we use ESD floor (vinyl) with Cu ground straps, tested at install.

Our coveralls, hoods, boots are conductive material and our gloves are ESD Nitrile safe.

We use wrist straps that are tested at the work area every time a person uses the tool, strap goes on either the fabric cuff or glove. All of our workstations where we handle ESD material have tested conductive laminate or mats with ground straps. All work stations are tested yearly.

This work is done in an ISO-6 room (Class 1000). RH control is 45% +-3% but you still need ESD control as wafers tend to charge up during processing. All our cassettes and wafer boxes are stat-pro 100 black in color. The other thing to watch out for is electrical test probes; you must always ground all probes before testing your device. Some test equipment does not ground the output pins and coax lines can build up a large charge and zap your device.

The thing about ESD damage is that you cannot always see it and it is then a latent defect waiting to eat your lunch later.

Hopes this helps

Rick

Draper Laboratory
Principal  Member of the Technical Staff
Group Leader Microfabrication Operations
555 Technology Square
Cambridge Ma, 02139-3563

www.draper.com
rmorrison at draper.com
W 617-258-3420
C 508-930-3461

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 11:05 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<mailto: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<mailto: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> [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<mailto: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

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Dr. Loïk Gence

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

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