SpecMat Proposal: Polystyrene Nanoparticles

Mary Tang mtang at stanford.edu
Mon Feb 6 11:06:54 PST 2006

Hi Chris --

Sorry for the delay.  Your Specmat request was approved, with a few 
caveats.  Please let us know if there are concerns on your part for any 
of these.  From our notes, we have the following:

1.  SiO2 deposition on silicon wafers.
2.  Spincoating of polystyrene microspheres, to be performed at Prof. 
Wang's lab.
3.  RIE using drytek2, using CF4/O2 in 2:1 ratio.  *SpecMat requests 
that you perform a 15 minute O2 plasma clean following your process, to 
remove any polystyrene spheres that may have come off the wafers.
*4.  Etching on the AMTEtch through SiO2.  *SpecMat requests that you 
perform the 5 minute NF3 cleanup in the recipe 2 after processing your 
wafers (this is part of the standard procedure for this recipe.)*
5.  Remove polystyrene microspheres using dichloromethane.  *SpecMat 
requests that if this is to be done at wbsolvent at SNF, that an 
alternative to dichloromethane be considered, as this is a known 
carcinogen.  If this is to be done in Prof. Wang's lab, then please use 
glassware that has not been exposed to metals (as in liftoff.)*
6/7.  Wafer decontamination at SNF.  *SpecMat requests that you use the 
5:1:1 Water:HCl:H2O2 cleaup used for decontaminating wafers exposed to 
KOH etching.  This is available online at:  
http://snf/Equipment/wbgeneral/KOHEtch.html#Decontamination  Following 
these procedures, "lampoly" can be used.  (Please note that normally 
before going into a "clean" furnace process, a piranha clean at 
wbnonmetal and pre-diff clean at wbdiff are required.  However, since 
lampoly runs at a low process temperature, the KOH decontamation [in 
appropriate labware, if done at wbgeneral] properly done, should be 
sufficient in controlling contamination.  If you wish to change your 
process from lampoly in the future, please submit a SpecMat request so 
that we can check for the appropriate cleans.)*

Thanks for your patience!


Chris Earhart wrote:

> Dear SpecMat Committee,
> I was curious if you had reviewed my application for the use of 
> polystyrene nanoparticles at SNF.  Please let me know when you have 
> any updates regarding my proposal, or if you have any questions that I 
> can address.
> Thanks,
> Chris

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

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