HBr usage in clean room

Mary Tang mtang at snf.stanford.edu
Tue Jan 11 13:31:30 PST 2005


Hi Zhigang --

I'm sorry, I realize I just approved your process, but it was pointed 
out to me that wet processing of HBr has been previously been banned 
from the lab... The concern is for the handling and storage of 
hydrobromic acid in the presence of strong acids and bases, as it will 
form Bromine gas. At the wet stations, where there are multiple users, 
it is difficult to ensure that there will be no contact with acids or 
bases.

Are there wet benches in the Harris lab which you could use for your 
work? There are labs in chemistry, where HBr is frequently done, which 
might work for your needs.

Again, I'm really sorry, but I hadn't thought it out. I'm afraid this 
means that we cannot allow you to do this process in the lab... Could 
you please remove your HBr bottle from the lab? If you need help in 
finding where else you can store it, or in finding ways to transport it, 
let me know.

Again, my apologies -- please let me know what we might be able to do to 
help...

Mary

Zhigang Xie wrote:

>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. 
>


-- 
Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
CIS Room 136, Mail Code 4070
Stanford, CA  94305
(650)723-9980
mtang at stanford.edu
http://snf.stanford.edu




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