[Fwd: HBr usage in clean room]

Jim McVittie mcvittie at snf.stanford.edu
Tue Jan 11 14:01:06 PST 2005


As I recall, the previous request was for using Br not HBr. HBr is a bit
better than Br but I agree there is concern in using it in a common wet
bench.  Br has a exposure limit of 0.1 ppm while the limit for HBr is 3
ppm and for HCl is 5 ppm.


John Shott wrote:

> Mary et al:
> I'm sorry to be contributing to this discussion so late ... I think
> that I must have missed this when I was in Denver.
> However, if I'm not mistaken, at one point we had NOT allowed HBr in
> the lab based on the fact that it would have to be used at wbgen and
> that it's got serious chemical reactivity problems ... if I remember
> correctly, it's exceedingly reactive with nitric acid and we didn't
> feel that we had the controls in place to insure that nitric and HBr
> wouldn't be in and around the wet bench at the same time.
> My memory may be bad on this subject ... Jim or Mike may have better
> recall than I .... but I think that an argument can be made that use
> of HBr in a shared laboratory environment may not be a great idea.
> I apologize again for not jumping in before now .... I must have
> missed this either when I was trying to read email over a slow modem
> from Denver last week or when I was wading through the large volume of
> e-mail in my mailbox upon my return.
> Comments from other members?
> Thanks,
> John
> Mary Tang wrote:
>> Hi all --
>> Zhigang stopped by and asked about the status of this request.  It
>> looks fine to me, so with Mahnaz' OK, I've approved it.  Zhigang
>> will collect waste locally and label appropriately.  As he plans to
>> use this chemical frequently, the chemical will be stored in the
>> original container, labeled with his contact info, in the chemical
>> passthrough area for personal chemicals (there is room there.)
>> Mary
>> -------- Original Message --------
>> Subject:     HBr usage in clean room
>> Date:     Thu, 06 Jan 2005 18:02:01 -0800
>> From:     Zhigang Xie <zxie at stanfordalumni.org>
>> To:     <specmat at snf.stanford.edu>
>> Dear committee,
>> As a formal new material request, I put three file related to
>> Hydrogen Bromide
>> (HBr)here: MSDS pdf file,
>> text file for filling the form,
>> word file to describe the process I will use. I plan to use this
>> chemical frequently, so a storage place inside clean room
>> is ideal.
>> Thanks,
>> Zhigang Xie (coral ID: zxie)
>> ____________________________________________________________________
>>     --------------------------------------------------------------
>> 1. Requestor name: Zhigang Xie
>> 2. Phone number: (650)7238040
>> 3. email address: zxie at stanford.edu
>> 4. Requestor’s PI (Advisor) or Company:
>> J. S. Harris and G. S. Solomon.
>> 5. The name of the new Chemical (give all names commonly used):
>> hydrobromic acid (HBr)
>> 6. If there are secondary new chemicals that must be used with this
>> material, such as a developer for a new resist, list each of them
>> here and supply MSDSs for each of them.
>> N/A
>> 7. Name of vendor/manufacturer that you are planning to obtain this
>> material from:
>> VWR international
>> 8. URL for vendor’s website where info on the proposed chemical can
>> be found:
>> www.vwr.com
>> 9. Vendor’s address and phone number:
>> San Francisco Regional Distribution Center
>> 3745 Bayshore Blvd.
>> Brisbane, CA 94005
>> Orders: 1-800-932-5000
>> Web Orders: www.vwr.com
>> Phone: (415) 468-7150
>> Fax: (415) 468-1105
>> 10. What is your reason for wanting to bring this material into the
>> lab:
>> For etching of GaAs and AlGaAs with enough smoothness and roundness
>> for optical device fabrication.
>> 11. Make a strong case why you can not use an already approved
>> chemical/material for this purpose:
>> HBr is the standard chemical for making my devices according to
>> publications. Try to find alternative, but it is impossible.
>> (Note that all previously approved chemicals are listed in the MSDS
>> Index binder located in the receiving area. Also see SNF Index of
>> MSDS Sheets.)
>> 12. List all the lab equipment and wet benches that you propose to
>> use with this chemical:
>> Only GaAs wet bench.
>> 13. Proposed quantity of the chemical that you want to bring into
>> lab (give both raw and mixed quantities):
>> the order for VWR is one bottle (500ml)
>> 14. State the form that the proposed chemical is in. (Is it solid,
>> powder or liquid? Note: as a general rule, powders are not permitted
>> in the cleanroom.):
>> It is liquied (acid)
>> 15. State whether the chemical needed to be mixed to use it:
>> It need to mix with H2O2 (peroxide) in very diluted solution.
>> 16. From manufacturer, vendor or the Stanford safety site, obtain a
>> legible Material Safety Data Sheet (MSDS) for all the proposed
>> chemicals. Send these to the person listed below.
>> Please see the attached PDF file.
>> 17. If 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.
>> It will not be used in "clean" equipment.
>> 18. 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.
>> 19. Determine whether there is enough room to store your material in
>> the designed lab storage areas. 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.
>> As an inorganic Acid, it should be in storage group F.
>> 20. In your discussions with vendors, try to determine the best way
>> to dispose of your spent chemicals and by-products. The lab has
>> acid/base, HF and solvent drains. The acid/base drains go to a
>> neutralization system before going the city waste water system. The
>> city of Palo Alto has tight limits on the amount of heavy metals
>> that be disposed of through the waste water system. If your chemical
>> contains any metals, there is a good chance that you will have to
>> collect all your waste and dispose of it in labeled containers which
>> are picked up the Health and Safety Department. The HF drains go to
>> a central tank which is pumped out by a HF disposal service at
>> considerable expense on a regular basis. The solvent drains in the
>> solvent benches are collected under the benches and disposed of by
>> Heath and Safety as needed.
>> I intend to keep the spent chemical and by-products in a plastic
>> bottle for EH&S to pick up. (After discussions with vendors, it
>> seems OK to get aspirated, but it wait for the committee to
>> approve.)
>> 21. Put together a detailed process flow description on how you
>> proposed to use this chemical. This should include: Any chemical
>> mixing, all lab equipment and wet benched to be used, all containers
>> to be used, where chemical is to be stored and how chemical and
>> by-products are to be deposed of. This should be in a Word file
>> attached to your e-mail request. In reviewing your procedure, we
>> will be most interested in how the safety and contamination issues
>> are to be dealt with.
>> See the attached word file.
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