Hi there,

     At our lab, we boil Piranha at 120C.  As far as the time is concerned, the
thicker the resist and the denser pattern, the longer it takes.  At the
thickness of 15 microns and generally moderately dense, we usually give it
a good half an hour.   Anyway to ensure it removes all resist, you can
leave it a bit longer in Piranha.   When you see scum of photoresist on the
surface of Piranha solution, it usually means you need to add more H2O2.
When you do add H2O2, the resist scum will disappear because it reacts with
H2O2 and becomes gases.

Cheers,
Wutthinan


> Holy cow... are you sure this won't explode?
>
> Jie
>
> On Wed, Jun 23, 2010 at 1:26 PM, Jesse D Fowler 
wrote:
>
>> Piranha (in my case 4:1 H2SO4 : 30%H2O2) boils at 160C. It is much more
>> aggressive at this temperature. (also very dangerous!)