mwiemer at sj-solar.com
Tue Mar 17 18:04:03 PDT 2009
We will use the acid this week!
From: Mahnaz Mansourpour [mailto:mahnaz at stanford.edu]
Sent: Tuesday, March 17, 2009 2:13 PM
To: Mary Tang
Cc: Mike Wiemer; specmat at snf.stanford.edu; Senyo Dogbe
Subject: Re: Iodic Acid
I am okay with this.
Mary Tang wrote:
> Looks good to me -- any objections, SpecMat'ers?
> Mike Wiemer wrote:
>> Iodic Acid Procedure
>> 1.) We will mix the powder into solution using the acid hood in the
>> dicing saw room (0.2M/L solution).
>> 2.) The powder will be stored in the acid vault.
>> 3.) The acid will be brought into the lab either through the chemical
>> passthrough or the cleanroom "back door" using a bottle carrier
>> 4.) The mixed acid will be stored in the chemical passthrough in a
>> dark brown bottle (with a yellow label of course)
>> 5.) All etch waste will be collected and tagged and placed in the
>> proper chemical passthrough area
>> 6.) Waste acid which has not etched material will be aspirated
>> *From:* Mary Tang [mailto:mtang at stanford.edu]
>> *Sent:* Tuesday, March 17, 2009 9:53 AM
>> *To:* Mike Wiemer
>> *Cc:* specmat at snf.stanford.edu; Senyo Dogbe
>> *Subject:* Re: Iodic Acid
>> Hi Mike, Senyo --
>> Thanks for the reminder... Just a couple of things.
>> 1. Powders (including crystals -- as well as free nanoparticles and
>> nanotubes) aren't allowed in the cleanroom. It's just too difficult
>> to handle powders (dispensing, weighing, mixing) when there's laminar
>> flow and exhaust blasting in different directions. You can, however,
>> mix solutions from powders outside the cleanroom, in the wafersaw
>> room, and bring them in, either through the chemicals passthrough
>> (get a staff member to help you with access) or using a single bottle
>> carrier through the service area in the back. Alternatively, if you
>> can find a source of pre-mixed solution, you won't have to mix it up
>> 2. Can you store the solution for an appreciable time or does it have
>> to be mixed up just before use? If you store the bottle of solution,
>> it should be kept in the chemicals passthrough. Make sure to get a
>> yellow label. I take it that a brown bottle should be sufficient for
>> excluding light -- if you decide to also wrap it in foil or other
>> covering, make sure to label the outside of the foil with all the
>> critical info as well.
>> 3. Crystals should be stored outside the lab. We have a corrosives
>> room where this can be stored. However, you'll need staff help to
>> access the vault, so this will limit availability to working hours.
>> 4. How will you be disposing of the waste? If you are etching
>> III-V's, then etchant waste should be collected locally and
>> appropriately tagged. The unused acid itself, I believe, can disposed
>> of by aspirating at the bench.
>> 5. Could you write up a procedure for this (like what you have below,
>> but with the where's and how's)?
>> Mike Wiemer wrote:
>> Hi Specmat,
>> We would like to use Iodic Acid in SNF. This chemical is commonly
>> used as an echant for III-V materials like InP. MSDS attached.
>> Iodic Acid comes in dry crystal form
>> One mixes the crystals with water to form the acid (0.2 M/Liter) in a
>> glass, non-transparent bottle (Iodic acid should be kept from light)
>> We will mix the crystals & water to create the solution at the GaAs
>> At the GaAs bench, we will combine: HIO3 (0.2M/L) : HCl : H2O - 1:1:x
>> where x goes from 1 to 100.
>> All work will be done at room temp
>> We will store the mixed solution in the personal chemical
>> pass-through area, along with the dry crystals
>> What do you think?
>> Mary X. Tang, Ph.D.
>> Stanford Nanofabrication Facility
>> CIS Room 136, Mail Code 4070
>> Stanford, CA 94305
>> mtang at stanford.edu <mailto:mtang at stanford.edu>
More information about the specmat