Application to use PEG

Mary Tang mtang at
Thu Jul 29 16:58:37 PDT 2004

Hi Umberto, Jun Xie --

Many apologies for the delay in getting back to you on this -- I'm
afraid we each thought the other took care of it...

Although in principle PEG is OK, there are some concerns:

1.  We do not allow powders or crystals in the lab, as they generate
particles.  So, please mix up your chemicals outside the lab.  You can
mix them up in your own lab, or mix them here, in the wafersaw room.  If
you have concerns about particulates, you can filter them in the lab (I
think PEG would be OK.)

2.  PEG is OK on the headway and on the hotplates.  However, please make
sure to use foil liners to prevent contaminating the station.  Please
also either avoid using cassettes or ensure they are clean after you use
them (yes, I know there's residual resist in most places, but we know
and understand resist.)

3.  Which etcher to do propose to use?  The DRIE etcher at SNF is the
STS etch system, which is a clean system and not compatible with your
materials (not to mention, probably of absolutely no use, since it's
good for etching silicon and not much else.)  Plasma etchers which would
probably serve your needs are the MRC and drytek1.

4.  PEG that is cured is fine for the contact aligners (I believe this
is what Jun Xie mentioned in our chat today.)

So,  in summary, the use of PEG, as discussed with Jun Xie (for headway,
hotplates, and aligner), is OK (Mahnaz and I have discussed this.)  The
PEG should be mixed outside the lab.  The etcher requires more



Umberto Ulmanella wrote:

> __________________
> To whom it may concern,
> I am contemplating the possibility of using PolyEthylene Glycol in my
> process. This material has unique biocompatibility properties and is
> suitable to be used in a cleanroom setting and to be integrated in
> MEMS devices, as proven in the literature. Please find attached the
> forms required in your website. Any suggestions regarding changes to
> equipment and/or procedures are welcome.
> Regards,
> Umberto Ulmanella

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

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