Dear Sharma ji,

There are many etchant for Alumina. The best one is the Potassium
Carbonate and Potassium bicarbonate mixture. This has been reported by
Team of IBM.

Another good etchant is mixture of Phosphoric acid H 3PO4 and Chromic
acid solution. To prepare this solution you can take 7 ml of
Phosphoric acid and add 4 gram of Cr2O3.

Or another way is to etch Alumina by NaOH and EDTA solution. Alternate
to NaOH is Tetramethylammonium hydroxide solution.

Bye the way, what type of Alumina you are using? Anodized Alumina or
Amorphous Alumina ceramic sheet? If it is Anodized Alumina, you can
find number of report / papers on this topic. Try sciencedirect or
scifinder for that....

HF will certainly not work.

Hope this will help you.

Best

Amit

> ---------- Forwarded message ----------
> From: jpt sharma <jptsharma at yahoo.com>
> To: mems-talk at memsnet.org
> Date: Wed, 10 Oct 2007 08:57:07 -0700 (PDT)
> Subject: [mems-talk] Al2O3
> I am looking for the AL2O3 wet etch chemical. Can anyone suggest me the chemical and vendor?

-- 
Dr. Amit Asthana
Brain-pool Scientist
Institute of Applied Chemistry and Biological Engineering
(IACBE), Polymer Derived Ceramic Material Lab,
Chungnam National University, 220 Kung-Dong, Yusung-Gu
Daejeon, 305-764, South Korea.
Phone: 042 821 8920 / 7684 (office)
Fax:     042 823 6665
Email: amitasthana4 at gmail.com
          amitasthana4 at yahoo.com

http://mail.mems-exchange.org/pipermail/mems-talk/2007-October/213469.html

Dear all,

as a part of my scientific work, I have to try to etch Al2O3
substrates by wet-etching methods.

First I tried to etch the Rubalit 708 96% (supplier CeramTec)
substrate with 85% -solution of Phosphoric acid and in a mixture of
water, phosphoric acid and nitric acid It etched slowly with the
etch-rate of approximately 37 nm/min.

After this short success, I changed to the Rubalit 710 99,6%
substrates and tried the same etching method, but this time nothing
happened even after the temperature of the solution had been raised up
to 85 C.

The question is, are there any differences in the structures of
Rubalit 708 and Rubalit 710 or any significant differences in a
production process which could influence the solubility of these
materials?

Does anybody know or have any experience in the chemistry of ceramics?

Many thanks in advance!

Regards,

Denis Petrov

http://mail.mems-exchange.org/pipermail/mems-talk/2008-October/242321.html

구글 al2o3 phosphoric etch 검색

ATOMIC LAYER DEPOSITION OF Al2O3, TiO2 and ZnOFILMS INTO HIGH ASPECT RATIO PORES

http://ieeexplore.ieee.org/iel5/4300055/4300056/04300182.pdf?arnumber=4300182