Michael,

The concentration of TMAH in AZ300MIF was very low (I think it is less
than 2%) for appreciable development rate at room temperature in AZ
P4000 series resist. AZ400K is KOH based solution with higher
concentration. But K ions may not be desirable for some applications.
Usually the thick film resist are not used for electronic application, so
it's ok. AZ300MIF is metal-ion-free (in ppb unit).

Yours sincerely,

Isaac Chan, Ph.D.
University of Waterloo

On Wed, 11 May 2005, haixinzhu wrote:

> I have a question on the difference between AZ400k and AZ300MIF developer
> used for AZP4620 photoresist. The official website
> http://www.az-em.com/products/na/photoresists/thick_film.html shows the
> developer is AZ300MIF, but I heard many people are using AZ400k developer.
>