request to bring new materials into the lab

Mary Tang mtang at
Thu Apr 29 08:07:58 PDT 2004

Sorry Marc --

I meant to get back to you...  Your request is a bit unusual, because as
far as I know, people don't do silanization on this scale in our lab.
Usually, researchers have their own labs with better means for handling
larger volumes of solvent than we do.  I don't know how many wafers you
intend to do at once, but a cassette usually means a liter at a time.

1.  You ask to use the spin rinse dryer after two solvent processes in
your process flow.  The first one, I'm a bit concerned about.  IPA
doesn't do anything to the spin rinse dryer (SRD), but any possible
residual APTES could be very bad (I'm assuming you are proposing to use
the SRD in litho, since it is gold-compatible, but APTES contamination
could change the surface properties of subsequent wafers processed
there.)  The second one isn't good either, in that DMF is a fantastic
solvent and may dissolve or penetrate any seals or plastic exposed in
the SRD.  I would suggest rinsing the wafers with a lot of water (at
wbgeneral, using a hand spray) and then using the dump rinser in litho,
before using the SRD.  I don't know if exposure to water is going to be
a problem for your particular process, but the SRD sprays with lots of
water before going into the dry cycle, so I would think that the
additional rinses should be no more of a process issue.

2.  No powders are allowed in the lab.  This is because powders have a
tendency to go everywhere, especially when handled in high velocity
hoods,  and result in particulate defects on other people's material.
So, any solution from powder must be mixed outside the lab.  This can be
done in the solvent or acid hoods in the wafersaw room.  You can bring a
concentrated solution made up outside, into the lab and dilute up to
meet your processing needs.

3.  Since you are plan to deal with fairly large volumes of solvent that
are not typically used in the lab, you should plan to collect your
solvent locally (obtain clean, defaced containers from the service area
and attach and properly label a hazardous waste tag, according to
wbsolvent procedures.)  I don't think DMF should be collected in the
plastic containers provided -- you will need to provide your own glass

4.  I'm afraid that we also don't have a lot of solvent storage space,
and it looks like you have a large volume of DMF.  I would suggest that
you obtain a smaller bottle, or plan to store the DMF only for a short
time (even two smaller bottles would be easier to store).  Please obtain
the appropriate labels from Mahnaz -- even though your bottles will
likely already have the appropriate label, we need to keep track of who
this belongs to.

5.  I would strongly suggest you get your own wafer cassettes.
Silanization can be poisoned by chemical contaminants, and there's no
telling what our teflon boats have undergone.  Also, the teflon boats
are generally not used for solvent processing, so your process may
actually end up contaminating them (teflon sucks up solvents, and DMF is
a very good solvent.)

Finally, I would suggest that if you have any fume hood resources in
your own lab, that it might be better to do this processing there.  As
you can see, we aren't really geared up to handle the 1 liter volumes
you are likely to use -- the station is not very ergonomic and a lot of
manual handling is required.  If you do decide to do this at SNF, please
get in touch with me or Uli to go over the logistics of handling large
volumes at this station.



MGlazer at wrote:

> Dear SpecMat,
> I wanted to check and see if there has been any consideration of these
> new materials.  Please let me know if I can answer any questions, or
> how I can help with the process.
> Sincerely,
> Marc Glazer
                                    To specmat at
                                       <specmat at>
  04/15/2004 04:19 PM
                                    cc mtang at

                               Subject request to bring new materials
                                       into the lab

> Dear SpecMat,
> My name is Marc Glazer (username mglazer).  I am working at Cell
> Biosciences, and have been doing some processing at SNF under the
> guidance of Mary Tang.  We would like to use a process to silanate our
> glass wafers.  This exact process was actually used at SNF several
> years ago by a consultant with whom we are working.  Attached is a
> document with all of the relevant information about each chemical, the
> MSDS of each chemical, and a description of the process flow.  Please
> let me know how I can help with the approval process, and if I can
> provide any additional information.  Thank you for your time in
> considering this.
> Sincerely, Marc Glazer

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

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