Zhiwei,

We had a large bath of H2SO4 we kept on a hot plate all week long for batch
dipping Si wafers.  We had to add H2O2 every morning before heat it up.
There is the order I used for years.

Hope this helps and don't get any on you!

Brent

Zhiwei Zou wrote:

>
> I am confused about the sequence of mixing these two chemicals. Some
> materials said add H2O2 to H2SO4 but others do it reversely.
> Who can help me to confirm it?
>