[labnetwork] Flooring - ISO 5/6
Loïk GENCE
Loik.gence at cetuc.puc-rio.br
Thu May 14 17:50:19 EDT 2015
Dear All,
I thank you for your comments. It helps.
The point about maintenance is important for us. Epoxi would require
pausing a whole fab for repairing only a few m2 of flooring... bad point.
It is true that, here, outside, humidity is very, very, very... high.
but we dimensioned the airconditionning to reach about 50 % relative
humidity inside of the cleanroom. I agree that without taking care of
the whole chain (operators, shoes, tweezer,...), ESD flooring is not
efficient, even useless. But, personally, I already killed "burned" a
few electrodes of MEMS devices just placing the substrate with my
tweezer under the microscope in a non ESD cleanroom...
I don't think ESD flooring is mandatory for a small cleanroom like ours,
but as the price difference is insignificant (exception for Epoxi ESD )
It is worth to choose an ESD flooring, as it should save at least a few
devices from sudden death (always the best ones)!
I thank you again for your precious time.
Best Regards,
Loïk.
Le 14/05/2015 13:14, Morrison, Richard H., Jr. a écrit :
>
> 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
>
> --
>
> __________________________________________
>
> 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 <mailto:loik.gence at cetuc.puc-rio.br>
>
> __________________________________________
>
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--
__________________________________________
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
(Mobile) +55 (021) 99156-5558
loik.gence at cetuc.puc-rio.br
__________________________________________
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