Silica Particles

Mahnaz Mansourpour mahnaz at
Mon Sep 26 13:45:43 PDT 2011

Hi Mark --

My sincere apologies.  I usually handle nanoparticle requests, but must 
have completely missed your previous email, so you haven't heard from us.

We don't generally allow nanoparticle solutions into the cleanroom or 
cleanroom processing tools though there are a few exceptions.  For spin 
coating, we don't allow silica nanoparticle solutions in the cleanroom 
tools because it is remarkably difficult to keep them clean and avoid 
have them redeposit on other peoples' substrates.

So, for what you describe here, we have a spin coater located outside 
the lab, in the "wafersaw" room.  It is not really clean by 
microcontamination standards, but it is ventilated and the air is 
filtered.  Mahnaz Mansourpour trains on this system.  It's a nice, 
manual, Laurell coater (better and newer than the general spinner inside 
the lab.)

By the way, are you trying to create a monolayer of silica particles? 
If so, you should make sure to get surface-modified beads -- either all 
with carboxylate (negative) or amine (positive) chemical groups.  The 
charge really helps a lot in distributing particles and prevents their 
clumping.  Unless you already have a protocol of your own, I may be able 
to dig up a couple from people who have done it here.


Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
Paul G. Allen Room 136, Mail Code 4070
Stanford, CA  94305
mtang at

On 9/26/2011 11:49 AM, Mark Dante wrote:
> Hi,
> I submitted several materials to be approved for clean room use about 1
> month ago. Do you have any idea when I will be hearing back about these
> materials? I'm very anxious to get this project started with the help of
> SNF. My previous email, along with the required documentaiton is attached
> below,
> Mark Dante
> ---------- Forwarded message ----------
> From: Mark Dante<mark.dante at>
> Date: Tue, Aug 30, 2011 at 4:20 PM
> Subject: new materials
> To: SpecMat at
> Hello,
> I'd like to submit the following substrate and silica nanoparticle solution
> for use in the SNF. Please let me know if I need to provide you with any
> other information. Thanks so much.
> Mark Dante, Ph.D.
> Scientist/Project Manager
> ThinSilicon Corporation
> 1400 N. Shoreline Blvd, Suite B-3
> Mountain View, CA 94043
> (515) 451-1392

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