Hi Jeaneth,

It depends on what you mean by "clean."

If you only need to get rid of organic yuckiness, Piranha etch (10%
H2O2, 70% H2SO4, 20% H2O, at 100+ deg C) will do the trick. Some people
(like me) prefer to degrease substrates in sequential baths of
trichloroethylene, acetone, and methanol, which is good enough for mild
contamination.

If you are worried about particles or adsorbed ions, then you also need
to use the standard cleans SC-1 (1:1:4 of 15 M NH3 : 30% H2O2 : H2O, at
75-80 deg for 10 min) and SC-2 (1:1:4 of 12 M HCl : 30% H2O2 : H2O, at
75-80 deg for 10 min).

The SC-1 and SC-2 will leave you with an oxidized surface. If this is a
problem, finish up with an etch in buffered HF. This will give you a
H-terminated surface, but its stability will depend sensitively on your
lab environment (minutes to hours)

Of course, you should make sure to use electronic grade chemicals
(often cleaner and cheaper than analytical chemicals!), and ultrapure
H2O (18.2 Mohm-cm resistivity). In addition, each step must be followed
by thorough rinsing.

If you like, I can give you a more detailed procedure off-line.

A good reference is the Handbook of Semiconductor Wafer Cleaning
Technology; Kern, W, Ed.; Noyes: Park Ridge, NJ, 1993.


On side note, I've met people who had major problems with fluoropolymer
from Bosch etching, which stubbornly adhered to their structures'
sidewalls even against Piranha and oxygen plasma. Anyone heard of this
problem?

Cheers,
Simon Garcia


On Jul 14, 2005, at 12:47 PM, Jeaneth Corredor wrote:
> I need to clean a silicon surface.  I know that it
> should be made with HF but I don't know the details of
> the procedure of cleaning.
> can some of you give me this information? thank you
> Jeaneth.-
>