Hello,

I'm wondering if  the KOH concentration for anisotropic etching is always in
wt % (weight percentage)?

For instance in Seidel and al., they use: 1L H2O +312g KOH +250ml IP, which
yields to


312g/(312g+1000g+250ml*0.785g/ml) = 20.6% or approximately 20%.


However, for the following recipe: 70g KOH pellets + 190mL DI water + 40mL
IP; I can not get the 30% KOH/Isopropanol etch solution as stated in
http://en.wikibooks.org/wiki/Microtechnology ?

Thanks for your help.

Cheers,

Badr Omrane