using mercury dibromofluorescein disodium salt in SNF...

Robert Huang roberth at
Wed Sep 9 17:22:06 PDT 2009


Thanks for your feedback.  I will follow your guidelines and contact the appropriate personnel to ensure I'm handling the material appropriately.  I will also talk to Uli about using wbsolvent vs. wbgeneral.



From: Mary Tang [mailto:mtang at]
Sent: Tuesday, September 08, 2009 1:56 PM
To: Robert Huang
Cc: specmat at; Uli Thumser
Subject: Re: using mercury dibromofluorescein disodium salt in SNF...

Hi Robert --

Unless others see a problem with this, I believe this is OK to use, with the following provisions:

1.  First, make sure to obtain the yellow label and barcode for this.  Contact Ed, Mahnaz, or me to register the bottle(s).

2.  Solid powders and crystals are not allowed in the lab.  You can dissolve the crystals in DI in the Wafersaw room.  Then, you can bring the solution into the lab through the chemical passthrough or service areas using appropriate secondary containment.  (If you are unsure of the procedure, please contact Uli or me.)

3.  For storing at SNF, please make arrangements to have the solid stored in the Flammables room (contact staff for access) and the solution in the personal chemicals area of the Flammables cabinet.

4.  Waste solution and the first three rinses should be collected locally and labeled as hazardous waste.  (Mercury has very bad environmental consequences -- DO NOT aspirate or dump waste into the sinks.)

5.  I know wbgeneral is more convenient because it's got water, but as this stuff is incompatible with oxidizers, it should be treated as a flammable.  So, wbsolvent would be a better location for this.  In my opinion, if you're using a small amount (like <100 ml) and low concentration (<few percent) then wbgeneral is OK; otherwise, wbsolvent should be used.  I will, however, defer to Uli on this.


Robert Huang wrote:

Hi Mary,

Yes, amazing that it is the same as what was widely used by many (including myself!) in the "old" days.  To answer your questions:

1)  If I successfully prove the technique (which is likely since it has been published and done by others), I will probably run it a few times over the next 2-3 months.

2)  It does not need to be in the yellow room.  I was thinking to use it at wbgeneral.

3)  To start, I will use enough to immerse 1 to a few wafers at a time in the solution.  Physical hardware may limit me from doing any more than a few at a time.

4)  Coating will be done at room temp.

5)  No other materials required (other than DI water to get it into solution).

6)  Yes, I would like to store the material at SNF.



-----Original Message-----

From: Mary Tang [mailto:mtang at]

Sent: Tuesday, September 08, 2009 12:49 PM

To: Robert Huang

Cc: specmat at<mailto:specmat at>

Subject: Re: using mercury dibromofluorescein disodium salt in SNF...

Hi Robert --

Gee, reading the MSDS, you wouldn't think this was the stuff that our

moms used put on cuts and scrapes. But it was taken off the market for a


First, some questions:

1. How often will this be used? Is it a one-time test or do you

anticipate frequent use?

2. Where will this be used? Does it need to be in the yellow room?

3. How much will you use? Enough to cover one wafer or 25?

4. Is this heated or at room temp?

5. Are there any other chemicals required for this process?

6. Do you plan to store the material at SNF?


Robert Huang wrote:

Dear SNF Specmat Committee:

I am interested in using mercury dibromofluorescein disodium salt

inside the SNF facility. First question - Is it perhaps already on the

approved list of materials that can be used in SNF? If not, I would

like to ask the committee's permission to use. My intent is to

dissolve the salt in DI water and submerge my 4" silicon wafers in the

solution in order to coat my wafers with the resulting photosensitive

material. Other names for this compound are:

1) 2',7'-Dibromo-5'-(hydroxymercurio)fluoresceindisodium salt

2) Merbromin

3) Mercurochrome

I'm attaching the MSDS from Sigma-Aldrich which is where I plan to

obtain the material. You can also obtain the document from their

website -<> <><>, using

product #M7011.

If any questions, please don't hesitate to contact me.


Robert Huang

Director, Process and Device Technology

QuSwami, Inc.

505 Montgomery St., Suite 300

San Francisco, CA 94111

415-834-9910 (Office)

408-854-0450 (Cell)

roberth at<mailto:roberth at> <mailto:roberth at><mailto:roberth at>


Mary X. Tang, Ph.D.

Stanford Nanofabrication Facility

CIS Room 136, Mail Code 4070

Stanford, CA  94305


mtang at<mailto:mtang at>
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