I want to propose a standing rule that whenever such hazardous
chemicals are suggested to users who are presumably unfamiliar with
them (since instructions on preparation are given), to include
precautions regarding use. In this case its necessary to note that
Piranha etch is known to explode if exposed to too much organic
material, hence should only be used to clean trace amounts of
impurity. And in general should be used with precautions equivalent to
those for hydrofluoric acid.

On Wed, Mar 10, 2010 at 2:21 AM, A.ALLOUCH  wrote:
> Hi,
>
> Another efficent method is to use Piranha ( H2O2+HESO4    1/1) put the H2O2
> before the acid in the beaker  and mix for 1 min, then put your wafer and
> wait for 2 mn and you will have very good results.
>
> Alaa