Initial discussion on working with SNF for processing PbS

Mary Tang mtang at
Thu Oct 25 15:35:31 PDT 2007

Hi all --

I just spoke with Jess and Jim Kruger.  Jim is doing the work.  Envisage 
would like to use our wafersaw/cmp room to spin coat or dip wafers in 
PbS nanoparticles from various solvents and then do some dry etching in 
the lab.  The  encapsulation is not likely to be done here since we do 
not have the capability they need.

I think that as long as they have good handling practices and don't 
store a lot of chemicals here, it would be OK for them to use the 
solvent bench and spin coater there as needed.  Jim is advising them on 
the dry etching and will keep them honest.  The only chemical I have 
some mild qualms over is chloroform, since its PEL is quite low, but if 
it's in the utility room and they are careful, I think it's not really 
too much of a problem.

What do you all think?  They want to join safety training on Monday.


Rick Clayton wrote:
> Hello;
> My name is Rick Clayton, and I am VP of Advanced Materials for 
> InVisage Technologies, an early stage (still stealth mode) technology 
> company working on advanced electronics.
> We wish to do work within the SNF, and I want to start the process of 
> material approval prior to full engagement.
> Many of the detailed questions below are more applicable once we are 
> more familiar with your facility, but I will provide a top level 
> description here as a first step in the process of getting our 
> material approved.
> Core material: PbS
> associated other materials: Thiols (Mercaptans): Ethane Thiol, Ethane 
> DiThiol, Benzene Thiol (may include other thiols in the future)
> process chemicals: toluene, chloroform, acetonitrile, acetone, hexane
> Incoming material:
> The PbS would be in either powder or solution (toluene, chloroform, 
> hexane, or other non-polar solvent). 
> Typically we would use about 50-100 ml of our material per day.
> a rough process flow:
> Our device involves spinning films of PbS onto a substrate (usually a 
> Si wafer), doing some solution processing of the wafer with the 
> thiols, depositing masking materials, etching the PbS film, and then 
> depositing encapsulation materials.  Once the wafer is finished we may 
> either die saw or test at wafer level. 
> We will be developing solvent systems and spin profiles to optimize 
> our films.
> We will be developing masking and etch processes
> We will be developing encapsulation processes
> ----------------------------------------------
> Please provide as much information as you can about your chemical or 
> material. It may very well be the first time anyone on the SpecMat 
> committee has heard of this chemical/material, so it will be your 
> responsibility to educate us. We also have a large archive of 
> chemicals and materials that have been approved, so we may also be 
> able to help you in selecting a chemical or process
>    1. *Your contact information:* Name, Coral login, phone number,
>       email address and who you work for (your PI or company.)
>    2. *The chemical or material. *Please provide all common names,
>       trade names, and CAS numbers where appropriate. Include an MSDS,
>       if available; or provide the reason, if not. Make sure to
>       include information for any new secondary chemicals (such as a
>       developer for a new resist). Read the MSDSs as well as the
>       Stanford Chemical Storage Groups
>       <> and the
>       Stanford Chemical Safety Data Base
>       <> sections
>       on this website to determine the Storage Group Identifier
>       <> and Main
>       Hazard Class
>       <> of your
>       chemical/material.
>    3. *Vendor/manufacturer info:* address and phone number, website URL.
>    4. *Reason for request:* Please give serious thought to this. If
>       you have any process information (application notes from the
>       vendor, protocol from another lab, experimental methods section
>       of an article), please include it, preferably as attachments.
>       Ask yourself these questions: Is this the latest procedure? Are
>       there newer/safer alternatives that will also work for my
>       project? Will any of the current SNF approved chemicals and
>       materials work for me?
>    5. *Process Flow:* Please provide a detailed process flow
>       description on how and where you proposed to use this chemical.
>       This should include *all* *Lab equipment
>       <> *to be used
>       for processing your wafers once your new chemical or material
>       has been used (even if your new material is a film that is
>       removed, it may still pose potential contamination concerns.)
>       Make sure to include wet benches. Please note that f the
>       chemical/material is to be used in any the "clean"
>       <>
>       equipment, purity specifications will be needed. This is most
>       important for chemicals/material that are not normally used for
>       VLSI device fabrication. To be allowed into a "clean" tool
>       <> ,
>       the material should MOS grade or better.
>    6. *Amount and form. *How much will you bring in? Is it solid,
>       powder <> or
>       liquid? (Note: as a general rule, powders
>       <> are not
>       permitted in the cleanroom.) Do you need to mix it to use it?
>    7. *Storage: *Will you be storing your chemical/material at SNF? If
>       so, please note any potential reactivities (this should be on
>       the MSDS). Storage groups
>       <> A,B,D and
>       L are stored in the yellow solvent cabinet in the furnace
>       support area, while storage groups
>       <> C, E, F
>       and G are stored on top of one of the Pass-through Carts. Ensure
>       your chemical container or material is properly labeled
>       <> . If there
>       is no available room, it must be stored by in the bulk storage
>       area. You will then need to obtain it from receiving area
>       personnel each time you want to use it and return it to them
>       when you are finished using it (or each time you leave the lab).
>       Note that there is no storage of chemicals/materials in the
>       processing lab or at any wet bench.
>    8. *DIsposal*: How will you dispose of any waste or excess chemical
>       or material? In your discussions with experts and vendors, try
>       to determine the best way to dispose of your spent chemicals and
>       by-products. Please refer to the SNF Labmembers Safety Manual
>       <> for the
>       different methods of waste disposal that are available in the lab.
> ----------------------------------------------
> Please get in touch about next steps.
> Thanks,
> Rick
> -------------------------------------
> Rick Clayton
> VP Advanced Materials
> InVisage Technologies
> mail: 101 College St., South Tower, Rm 312, Toronto, Ontario, Canada, 
> M5G 1L7
> Office: 416 673 6520
> mobile: 613 291 6578
> email: rick.clayton at <mailto:rick.clayton at>
> This email contains information that is confidential. The information 
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Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
CIS Room 136, Mail Code 4070
Stanford, CA  94305
mtang at

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